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(Received for publication, January 19, 1996, and in revised form, July 3, 1996)
From the ABSTRACT CCAAT/enhancer binding protein INTRODUCTION CCAAT/enhancer binding protein Expression of C/EBP Studies in 3T3-L1 adipoblasts have provided evidence for reciprocal
expression patterns of C/EBP There are an increasing number of genes known to be subjected to
transcriptional regulation by C/EBP To ascertain the role of the C/EBP EXPERIMENTAL PROCEDURES A genomic clone
including the C/EBP The
targeting vector was linearized by PvuI digestion. 20 µg
was used to electroporate 20 × 106 R1 ES cells (45)
with a Bio-Rad Gene Pulser at 260 V and 500 microfarads. Transfected R1
cells were then plated on gamma-irradiated G418-resistant mouse embryo
fibroblast feeder cells. Around 48 h after transfection selective
media containing 675 µg of G418/ml (50% active substance) was added.
After another 24 h new media also containing 2 µM
Ganciclovir (Cymevene, Syntex Inc.) was added. New selective media
(G418 + Ganciclovir) was added daily, and after 10 days surviving
clones were transferred individually to round-bottomed 96-well plates,
trypsinized, and then seeded onto two different flat-bottomed 96-well
plates, one with feeder cells and one without feeder cells. The cells
on the former plate were trypsinized prior to confluency, suspended in
fetal calf serum, 10% dimethyl sulfoxide, and frozen in the plate,
whereas the cells on the latter plate were allowed to reach confluency
and then used for DNA extraction according to the microextraction
method described by Ramírez-Solis et al. (46). DNA
was then analyzed by Southern blot to screen for homologous
recombination. In brief, microextracted genomic DNA was digested by 15 units/well of BamHI (high concentration, Life Technologies,
Inc.) in a total volume of 50 µl in a digestion mix including 100 µg of bovine serum albumin/ml, 1 mM spermidine, and RNase
A at 50 µg/ml. Digested DNA was separated on 0.6% agarose gels,
transferred to Hybond N membranes (Amersham Corp.), and hybridized to a
1.3-kb EcoRI/BamHI fragment (E1.3B), representing
the region 3
R1 ES cells with one
targeted C/EBP Blood was
obtained by decapitation and bleeding onto heparinized 35-mm cell
culture plates. The blood was collected with a small rubber policeman,
and 20 µl was added to 400 µl of 0.2% NaF, 0.9% NaCl solution.
Blood was centrifuged, and the glucose concentration in the supernatant
was measured in a Hitachi 917 spectrophotometer (Huddinge University
Hospital) according to standard methods.
Total RNA was isolated
from liver using the Ultraspec RNA isolation system (Biotecx, Houston,
TX), according to the manufacturer's instructions. 20 µg of total
RNA/well was fractionated on 1% agarose/MOPS/formaldehyde gels and
transferred to Hybond N filters. Prehybridization was performed at
+42 °C in 50% formamide, 1.5 × SSPE, 10 × Denhardt's,
1% SDS, 0.5 mg/ml fragmented and denatured salmon sperm DNA, 0.2 mg/ml
tRNA. Hybridization was performed at +42 °C with same buffer
composition as above with the exception that Denhardt's was lowered to
5 × and dextran sulfate was added to 10%. Probe concentration in
the hybridization was 2 × 106 cpm/ml buffer.
Densitometric analysis of the Northern blot signals was performed using
a Molecular Dynamics instrument and software.
Liver nuclear lysates for Western blot analysis were prepared by adding
an equal volume of 2 × polyacrylamide gel electrophoresis
reducing sample buffer to purified nuclei pellets (48) and then
carefully sonicated to shear DNA and heated at +100 °C for 3 min.
After correction for differences in protein concentrations between the
samples, 20 µl of the nuclear lysates were loaded on
SDS-polyacrylamide gel electrophoresis minigels. Western blot analysis
was then performed as described (42). Detection of total protein on the
transfer membranes was used as a control of protein loading and was
performed with the enhanced chemiluminescence protein biotinylation
system (Amersham Corp.) according to the manufacturer's
recommendations.
Tissues were
fixed in 10% neutralized formalin or frozen in liquid nitrogen.
Sections for analysis were prepared either with a cryostat or a
microtome after paraffin embedding. Fixed and paraffin-embedded
sections were stained with hematoxylin and eosin using standard
protocols. Oil Red O staining of fat in liver and white and brown
adipose tissue, periodic acid-Schiff staining of glycogen, and PCNA
immunostaining (monoclonal antibody number 19A2, Innovex Biosciences)
in liver were performed using standard protocols.
RESULTS To inactivate the C/EBP Heterozygous animals were interbred to obtain mice homozygous for the
mutated alleles. Fig. 1G shows a Southern blot analysis,
using the E1.3B probe, of a litter resulting from a representative
heterozygote intercross. The outcome of the intercrossings shows that
there is no significant negative selection against the mutation during
embryogenesis since C/EBP In addition to inactivation of
the locus, our targeting strategy with insertion of the neoR
gene in the opposite orientation within the C/EBP To demonstrate that the targeted event resulted in total elimination of
the C/EBP
Littermates in most litters showed
no obvious differences at birth. However, in about 20% of the litters,
most of the C/EBP As shown in Table I, there was a small but significant
difference in body weight at birth between the pups. Normal and
heterozygous pups had the same weight, whereas nullizygous pups weighed
10% less than their littermates. This weight difference is further
augmented at 7-10 h where the +/+ and +/
Body weights and blood glucose levels
Volume 271, Number 40,
Issue of October 4, 1996
pp. 24753-24760
©1996 by The American Society for Biochemistry and Molecular Biology, Inc.
*
, and§¶
Karolinska Institute, Department of
Biosciences at Novum S-141 57 Huddinge, Sweden and the
§ National Center for Human Genome Research, CGTB, National
Institutes of Health, Bethesda, Maryland 20892-1852
ABSTRACT
INTRODUCTION
EXPERIMENTAL PROCEDURES
RESULTS
DISCUSSION
FOOTNOTES
Acknowledgments
REFERENCES
(C/EBP) is
a transcription factor that has been implicated in the regulation of
cell-specific gene expression mainly in hepatocytes and adipocytes but
also in several other terminally differentiated cells. It has been
previously demonstrated that the C/EBP protein is functionally
indispensable, as inactivation of the C/EBP gene by homologous
recombination in mice results in the death of animals homozygous for
the mutation shortly after birth (Wang, N., Finegold, M. J., Bradley,
A., Ou, C. N., Abdelsayed, S. V., Wilde, M. D., Taylor, L. R., Wilson,
D. R., and Darlington, G. J. (1995) Science 269, 1108-1112). Here we show that C/EBP 
1mice have defects in the
control of hepatic growth and lung development. The liver architecture
is disturbed, with acinar formation, in a pattern suggestive of either
regenerating liver or pseudoglandular hepatocellular carcinoma.
Pulmonary histology shows hyperproliferation of type II pneumocytes and
disturbed alveolar architecture. At the molecular level, accumulation
of glycogen and lipids in the liver and adipose tissues is impaired,
and the mutant animals are severely hypoglycemic. Levels of
c-myc and c-jun RNA are specifically induced by
several fold in the livers of the C/EBP / animals, indicating an
active proliferative stage. Furthermore, immunohistologic detection
with an antibody to proliferating cell nuclear antigen/cyclin shows a
5-10 times higher frequency of positively stained hepatocytes in
C/EBP / liver. These results suggest a critical role for
C/EBP in vivo for the acquisition of terminally
differentiated functions in liver including the maintenance of
physiologic energy homeostasis.
(C/EBP)1 is the prototype member of the
C/EBP family and belongs to the basic leucine zipper class (bZIP) of
transcription factors (2, 3, 4). All members of the C/EBP family have a
C-terminally located basic leucine zipper domain that is responsible
for DNA binding and dimerization (5). Several members of this family
have been cloned from different species, for a review see Refs. 6, 7,
that are able to both homodimerize and heterodimerize with each other
and to bind the same C/EBP consensus DNA sites. These properties are
reflected in the high degree of homology of the bZIP domain (8). By
contrast, the transactivation and attenuation domains are located in
the N-terminal part (9, 10, 11, 12), where a relatively low level of homology
exists (8). Thus, the members of the C/EBP family are able to bind the
same DNA sites but differ in their transacting and attenuating
properties.
in rodents is restricted to certain tissues and
cell types (8, 13, 14). High expression levels are detected in liver,
white and brown adipose tissue, and placenta. C/EBP is also
expressed in the lung, mainly in differentiated type II cells (15), in
the intestine where it is found in differentiated enterocytes (16), in
the ovary during follicular development (17), and in myeloid cells
(18). Furthermore, expression has been described in adrenal gland and
skin (13), and at least in humans, also in pancreas and prostate (19).
The basis for the restricted and differential expression pattern of the
C/EBP mRNA is regulation at the transcriptional level (14). The
molecular mechanisms that control the expression of the C/EBP gene
have not been fully elucidated (20); however, the organization of the
promoter has been studied in detail (21, 22, 23). The results from these
studies suggest an autoregulatory mechanism that contributes to the
control of the expression of this gene (22, 23).
and c-myc (24). It has been
suggested that this is the result of negative regulation of the
C/EBP gene exerted by c-myc. Repression is mediated
through interactions of c-myc with the initiator element of
the C/EBP promoter (25, 26).
. Several of the target genes are
expressed in a cell-specific manner, e.g. albumin in
hepatocytes (27, 28) and uncoupling protein in brown adipocytes (29).
Furthermore, many target genes such as aP2 and SCD-1 (30,
31), GLUT-4 (32), PEPCK (33), aldolase B (34), and acetyl-CoA
carboxylase (35) are involved in carbohydrate and lipid metabolism
pathways. In addition, it has been demonstrated by two different sets
of experiments that C/EBP is of central importance in the process of
terminal differentiation of adipocytes. First, it was shown that
C/EBP antisense RNA blocks the differentiation of preadipocytes into
adipocytes (36, 37). Second, overexpression of C/EBP in different
fibroblastic cell lines is sufficient to induce adipocyte
differentiation (38, 39). C/EBP can induce growth arrest in
adipocytes suggesting that it may play a role in the regulation of the
balance between proliferation and differentiation (24, 40). It is also
conceivable that C/EBP contributes to the maturation of hepatocytes
and the maintenance of the differentiation state. Results from studies
on regenerating liver after partial hepatectomy clearly show a dramatic
decrease of the expression of C/EBP, of at least 5-fold, during the
proliferative phase (41, 42). Recently, growth arrest by C/EBP was
demonstrated by co-transfection of a C/EBP expression vector in a
variety of cell lines (12). The multiplicity of interactions of
C/EBP with a variety of regulatory elements of genes suggests a
central role for C/EBP in cell proliferation and differentiation and
in key metabolic pathways.
protein in vivo, we
have generated C/EBP-deficient mice by homologous recombination in
ES cells. Here we report that C/EBP is critical for the proper
development of both the liver and the lung since animals deficient in
C/EBP display gross abnormalities in these organs and die within
10 h after birth. In accordance to a previous report (1), we also
show that C/EBP is indispensable for postnatal maintenance of
systemic energy homeostasis and lipid storage. Furthermore, in
nullizygous livers c-myc, c-jun, and 
-actin
steady state RNA levels and PCNA/cyclin protein levels are increased
suggesting an active proliferative state.
gene was derived from an OLA 129-
GEM-12
genomic library by screening with a PstI/SstI
400-bp fragment representing the bZIP region of C/EBP as a probe. A
7.3-kb EcoRI fragment from the 12.6-kb genomic clone was
subcloned into a pBS ± vector (Stratagene). The subcloned
fragment contains sequences 3.4 kb upstream and 1.2 kb downstream of
the C/EBP gene. The 5
EcoRI site in the fragment is
derived from the GEM-12 linker, whereas the 3 site represents a
genomic EcoRI site. An 1133-bp
XhoI/HincII fragment, containing the
neoR gene driven by a TK promoter, was derived from the
vector pMC1neo poly(A) (Stratagene), optimized for neoR
expression in ES cells (43). This fragment was blunt-end ligated into
the MluI site within C/EBP in the opposite direction
compared with the transcriptional direction of the C/EBP gene. To
enable negative selection against random integration, a 1854-bp
XhoI/HindIII fragment containing the HSV
thymidine kinase gene driven by a polyoma virus enhancer (44) was
inserted into the HindIII/SalI site of linker, 5
of the homologous genomic sequence.
of the genomic sequence in the targeting construct (Fig.
1D). The 1133-bp XhoI/HincII TK
promoter-Neo-poly(A) fragment, derived from pMC1neo poly(A), was used
as a probe to verify that only one copy of the targeting construct had
been inserted into the genome.
Fig. 1.
Strategy for disruption of the C/EBP gene.
A, restriction map of the 12.6-kb genomic fragment
containing the C/EBP gene. The 7.3-kb EcoRI fragment used
for targeting vector construction and the 1.3-kb
EcoRI/BamHI probe (E1.3B) are indicated. C/EBP
is an intronless gene. The restriction sites indicated are as follows:
N, NruI; M, MluI; H,
HindIII; E, EcoRI; Bg, BglII, and B,
BamHI. B, targeting vector construction. The
neoR gene was inserted into the MluI site in the
opposite direction compared with the C/EBP gene, and the
tk gene was inserted 5 of the genomic sequence. The
neoR gene is driven by a HSV-TK promoter, whereas the
tk gene is driven by a duplicated mutant polyoma virus
enhancer (PYF441 Enh). C-D, homologous recombination
between the targeting construct and the C/EBP allele and the
targeted allele resulting from homologous recombination. Small
x in the mRNA represents stop codons introduced in the
C/EBP transcript by the insertion of the neoR gene.
E, Southern blot analysis of transfected and selected R1 ES
cell clones. The 10.5-kb wild type BamHI fragment from the
nontargeted allele and the 5.7-kb fragment from the mutated allele are
shown. F, Southern blot analysis of a litter from a
heterozygote intercrossing. DNA was digested with BamHI and
probed with E1.3B. The genotypes are indicated above the lanes. +/+,
wild type; +/, heterozygous; and /, nullizygous animals.
G-H, Northern blot analysis of liver RNA from a litter
resulting from a heterozygote intercrossing (same individuals as in
F). Hybridization with a 400-bp probe of the C/EBP bZIP
region detects both the 2.8-kb wild type C/EBP transcript and the
3.9-kb C/EBP:Neo fusion transcript (G). A neoR
probe detects the 1.1-kb Neo(+) mRNA, transcribed by the TK
promoter and the fusion transcript in +/ and / animals
(H).
/ Mice
allele were injected into C57BL/6 blastocysts and
implanted into F1 (CBA × C57BL/6) foster mothers.
Male chimeras were mated to C57BL/6 females to verify germ line
transmission by coat color. Agouti offspring was screened for presence
of the targeted C/EBP allele by Southern blot on tail DNA, according
to Laird et al. (47) using the E1.3B probe described above.
Heterozygous offspring was then intercrossed to obtain homozygous mice
with both C/EBP alleles targeted.
/ Mice
gene, a mutation was generated by inserting a HSV-TK promoter-driven
neoR poly(A)+ gene into the unique
MluI site at position +701 in C/EBP. Within the C/EBP
gene there are several in frame AUG translation start codons, but only
two AUG codons (+130 and +491) are used in vivo, giving rise
to two proteins, p42 and p30 (49, 50). Another AUG codon further
downstream of the MluI site was shown to be used only when
the other upstream AUG codons were deleted. By inserting the
neoR gene into the MluI site in the opposite
direction compared with the C/EBP gene, we introduced stop codons in
all three reading frames downstream of both AUG start sites. Thus, only
truncated protein products, lacking the DNA binding and dimerizing
domain (bZIP), are expected to be translated from the transcript of the
targeted C/EBP gene. Furthermore, since the nuclear localization
signal resides in the bZIP domain, the produced truncated proteins will
not be imported into the nucleus and will probably be rapidly degraded
in the cytoplasm. Fig. 1, A and B,
shows the construction of the targeting vector, including a flanking
tk gene to reduce the number of ES cell clones with randomly
integrated vector (44). Correct insertion of the neoR gene
was verified by sequencing of the NeoR:C/EBP boundaries (data not
shown). As shown in Fig. 1, C and D, homologous
recombination between the targeting vector and the C/EBP gene will
result in the introduction of a new BamHI site within
C/EBP, resulting in a BamHI fragment of decreased size
(5.7 kb) compared with the wild type 10.5-kb fragment. A representative
Southern blot analysis of microextracted DNA from transfected and
double selected R1 ES cell clones is shown in Fig. 1E. In
total, seven positive ES clones were obtained with a frequency of
homologous recombination of 1:38. The positive clones were expanded and
analyzed further with a neoR probe. To substantiate that the
event of homologous recombination had been correct,
EcoRI-digested DNA was probed with an
XhoI/HindIII neoR fragment from
pMC1Neo poly(A) that resulted in the expected hybridizing 3 fragment
of 3.25 kb and one 5 fragment of 7.3 kb. In addition, BamHI
digestion resulted in the expected 5.7-kb fragment, verifying that only
one copy of the targeting vector was present in the genome (data not
shown). Two positive clones (S12 and S18) were used for blastocyst
injections and generation of chimeric males. Germ line transmitting
chimeric animals were derived from both targeted ES clones and were
used to establish two independent heterozygous lines. The same
phenotypic effects were observed in / animals derived from both
lines.
/ animals were born approximately at
the expected 1:4 Mendelian ratio. A small reduction in the numbers of
/ animals was observed, but this decrease was not statistically
significant (27% +/+, 51.8% +/, 21.2% /, n = 425; 
2 test, p > 0.10).
Locus Occurs in the
Absence of the C/EBP Protein
gene was designed
to test whether efficient and sustained transcription of the locus is
possible without the positive autoregulation by the C/EBP protein.
In such case a 3.9-kb transcript should be detected in C/EBP /
mice using either a C/EBP or a neoR probe. The data
presented in Fig. 1G, demonstrate that a neoR:C/EBP
fusion transcript of 3.9 kb appears as a result of transcription of the
targeted C/EBP allele, not only in the +/ mice but also in the
/ animals. As expected the fusion transcript is also detected by
the neoR probe as shown in Fig. 1H, suggesting
that C/EBP gene transcription occurs in the absence of the C/EBP
protein. Perhaps other C/EBP family members are able to compensate for
the loss of C/EBP. This notion is supported by transient
transfection experiments that show transactivation of the C/EBP
promoter by C/EBP (22). Finally, the appearance of both bands in the
heterozygous animals shows that both C/EBP alleles are
transcribed.
protein, liver nuclei lysates were analyzed by Western
blot analysis that was performed on pups from several litters. The
results from one such experiment are shown in Fig.
2A, verifying that the C/EBP protein is
completely absent in livers from nullizygous animals. Two other members
of the family, C/EBP and C/EBP
, were analyzed in parallel. As
shown in Fig. 2, B and C, no overt differences
could be demonstrated between the three genotypes.
Fig. 2.
Western blot analysis of liver nuclear
lysates from a heterozygote intercrossing litter. a,
detection by specific antibodies directed against C/EBP shows no
detectable levels of C/EBP protein in / animals. b
and c, the same liver nuclear lysates as in a
using antibodies against C/EBP and C/EBP illustrate that both of
these proteins are expressed in all littermates. d, total
amount of protein in each lane visualized by the protein biotinylation
system (Amersham Corp.). CRM indicates nonspecific
cross-reacting material. The same filter was used in
b-d.
Nullizygous Mice Die in the First 10 h after
Birth, but Some Die at Birth
/ pups died virtually at delivery. The
majority of these born almost dead (BAD) mice died immediately after
birth, while a few were able to survive for a shorter period of
approximately 30 min. Dissection of these animals showed the presence
of bubbles in their stomachs. BAD mice are, in general, born in large
litters (9.4 ± 1.6 pups, n = 10 litters). The
reason why this phenomenon only occurs in about 20% of the C/EBP
/ mice and only in large litters remains unclear.
pups have increased their
body weight by 15-20%, while the C/EBP / animals have not
gained any weight at all. These nullizygous animals, although
apparently normal at birth, gradually become weaker, and most of them
were never able to start feeding. After 7-10 h severe symptoms of
hypoglycemia, such as lethargy and shivering, were manifested, and
these animals died soon after. Although some / pups clearly were
able to start feeding, they did not survive more than 20 h.
Dissection revealed that these mice had milk in their stomachs.
Finally, in very few cases (less than 1%) nullizygous mice were able
to survive for a considerably longer period of up to 4 weeks of age.
These long term survivors are severely retarded in development. At
around 2 weeks of age they are about half the size of their
littermates. These animals are very thin and skin problems were
observed with flaking from large areas of the body before fur
outgrowth. This is a very rare but reproducible phenotype.
Genotype
Weight
Glucose
g
mM
At birth
+
/+
1.29 ± 0.15, n = 14
1.24
± 0.34, n = 5
+ /
1.31
± 0.15, n = 28
1.20 ± 0.54, n = 15
/1.18 ± 0.13, n = 14
1.20
± 0.57, n = 3
7-10 h postpartum
+
/+
1.53 ± 0.14, n = 21
4.33
± 1.18, n = 12
+ /
1.51
± 0.15, n = 27
5.09 ± 1.65, n = 16
/1.24 ± 0.13, n = 18
0.13
± 0.05, n = 7
Since C/EBP has been shown to regulate several genes involved in
carbohydrate and lipid metabolism, the dramatic effects on the early
postnatal survival in nullizygous mice could be due to low blood
glucose levels, similar to the phenotype displayed by the
C14Cos albino deletion mice (51). We therefore tested the
blood serum levels of glucose in newborn litters and in litters at the
time point when knockout animals usually die (7-10 h). The results
from these tests, shown in Table I, clearly demonstrate that there is a
dramatic drop in blood glucose levels some hours after birth in the
/ animals when compared with their +/ and +/+ littermates. Low
glucose levels between 0.1 and 0.2 mM are detected within
1 h postpartum (data not shown), but the animals survive for an
additional 6-10 h. This is consistent with the results of an earlier
report (1). We have also investigated the serum lipid levels at birth
and around 10 h postnatally. No statistically significant
differences for either cholesterol or triglyceride levels were
detected.
Nullizygous Mice Have Disturbed Liver Architecture,
Immature Pulmonary Phenotype, and Fail to Accumulate
Lipids
Histologic analysis of litters from heterozygous
intercrosses, performed either at birth or at 7-10 h postpartum,
revealed striking differences in liver, lung, and adipose tissues when
/ animals were compared with the other two genotypes. The hepatic
architecture of the nullizygous mutants was severely distorted with
acinar formation. The liver morphology also had a clear resemblance to
regenerating liver following partial hepatectomy or pseudoglandular
hepatocellular carcinoma. The number of biliary canaliculi in the
C/EBP / liver is considerably higher compared with both +/+ and
+/ liver (Fig. 3, upper lane). Hepatocytes
from nullizygous animals appear to have a smaller cytoplasm/nucleus
ratio, which may explain the dilated bile canaliculi. However, no
choleostasis or bile thrombi were observed. Liver sections of
littermates using periodic acid-Schiff stained for glycogen at birth
and 10 h postpartum showed that the normal and heterozygous
animals contained substantial amounts of glycogen, whereas the /
mice had drastically decreased but detectable levels (data not shown).
It has been suggested that the distorted architecture may be due to the
deficiency in fat and glycogen stores in the cytoplasm that results in
smaller hepatocyte volumes (1). An alternative explanation may be that
genes involved in the cytoskeleton formation in hepatocytes are targets
of C/EBP regulation resulting in an imperfect three-dimensional
structure.
Fig. 3. Liver architecture and lung morphology are distorted in C/EBP
/ animals. A representative series of
histologic sections of liver and lung tissues stained with hematoxylin
and eosin. Note the acinar formation in the livers of C/EBP /
mutants. Pulmonary histology of newborn littermates indicates h.
Hyperproliferation of type II pneumocytes in C/EBP / mice and
results in reduction in the alveolar airspace (arrow, middle
right panel) and interstitial thickening (arrow, lower right
panel).
Lipid accumulation in both white and brown adipose tissue is dependent
on C/EBP (36, 37). To investigate the effects of C/EBP deficiency
in lipid storage, we performed histologic analysis of adipose tissue.
In newborn mice there are detectable fat depots in white adipose tissue
localized to the inguinal region and considerable amounts in the brown
adipose tissue. Although cells mass and general histologic appearance
of the brown adipose tissue was not altered, the fat depot was greatly
reduced in the C/EBP / mice, as seen by Oil Red O staining (data
not shown). Thus, unlike the situation in the liver, C/EBP
deficiency does not affect the overall brown adipose tissue morphology
but is rather specific for the accumulation of lipids.
All C/EBP / mice displayed irregular pulmonary histopathology.
Although location of the lungs of C/EBP / mice was comparable
with the normal littermates, embryonic, fetal, and neonatal development
of the airways was abnormal (Fig. 3). In mutant mice the lungs showed
hyperproliferation of type II pneumocytes and bronchiolization of the
alveoli. The primitive-appearing lung resembles the appearance of the
lungs of premature human infants. C/EBP / mice, particularly of
the BAD type, had clinical symptoms of a respiratory nature, suggesting
a role for C/EBP in the normal development of the lung. However, in
spite of the immature histologic phenotype of the mutant lungs, we did
not detect any significant changes at the protein expression level of
some key respiratory epithelial cell-specific molecular markers. Thus,
unlike the pulmonary pathology observed in TGF-3 and GM-CSF
nullizygous mice (52, 53) C/EBP deficiency did not alter the
expression patterns of surfactant protein C (proSP-C), thyroid
transcription factor-1 (TTF1), and Clara cell secretory protein
(CC10).2 Although we did not see any
effects on the expression of these important proteins that are markers
for a highly differentiated state of the lung, the observed respiratory
problems could be explained by an inadequate expression of other
surfactant apoproteins than SF-C. Interestingly, the promoter of the
major surfactant protein, SP-A, was recently shown to contain three
potential C/EBP binding sites (54). Since surfactants are
lipoproteins, another possible explanation for respiratory dysfunction
could be that the lipid production in the lung is affected by the
C/EBP deficiency, resulting in inadequate production of functional
surfactant.
/ Mice
The distorted liver architecture of the
C/EBP / mice is indicative of an active proliferative state. To
investigate the molecular mechanisms that may underlie these
differences, we analyzed the transcription rates and steady state
levels of genes that may be important in maintenance of the balance
between proliferation and differentiation in hepatocytes. We chose to
test the expression levels of albumin and -fetoprotein as markers
for hepatocyte differentiation and tumor development, respectively. In
addition, we tested -actin, c-myc, and c-jun
that correlate well with active cellular proliferation. Total liver RNA
isolated at birth and several hours later was compared among
littermates. A representative Northern analysis is shown in Fig.
4, and densitometric analysis of these experiments is
shown in Table II. mRNA levels of albumin were
reduced in C/EBP / animals, especially in the livers of newborn
animals. By contrast, -fetoprotein expression levels were increased
about 2-fold. This is indicative of a more de-differentiated state of
the C/EBP / hepatocytes. Levels of the -actin RNA were
induced by 3-fold suggesting a proliferative state. However, the most
predominant change, in addition to changes in the expression of genes
involved in glycogenesis that were demonstrated in an earlier report
(1), was the induction of c-myc and c-jun RNA
(Fig. 4 and Table II). Steady state c-jun RNA levels from
livers of both newborn and 7-h-old C/EBP / mice were increased
by about 10-fold. Induction of c-myc RNA was pronounced in
livers of 7-h-old / mice (Fig. 4 and Table II). These findings are
consistent with the patterns of expression observed in the early
regenerating mouse liver. In addition, early stages of experimentally
induced hepatocellular carcinoma in rodents display a similar
expression pattern for these genes (55).
Fig. 4. Pronounced induction of c-jun and c-myc RNA in C/EBP
/ mice. Northern blot
analysis of RNA extracted from livers of newborn and 7-h-old animals. A
total of 3-4 animals of each genotype were used from each time point
in three independent experiments. A representative Northern blot is
shown.
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|||||||||||||||||||||||||||||||||||||||||||||||||||||
Since C/EBP and c-myc are reciprocally regulated in
adipocytes (24) and hepatocytes (26), it is possible that
c-myc induction is a direct effect of C/EBP deficiency.
However, a more likely explanation is that c-myc induction
reflects the critical role of this molecule in mitogenesis and
transformation (56) and, together with the c-jun induction,
is indicative of the proliferative stage of the C/EBP /
hepatocytes.
Because proliferating hepatocytes and hepatocellular carcinoma cells
have induced levels of proliferating cell nuclear antigen (PCNA/cyclin)
(57), we performed immunohistostaining with an antibody to PCNA/cyclin.
The results presented in Fig. 5 illustrate a 5-10 times
higher frequency of positively stained hepatocytes in C/EBP /
liver, further supporting the notion that an increased portion of the
nullizygous hepatocytes are in the G1/S phase of the cell
cycle. Thus, loss of C/EBP has an effect on the proliferative
potential of hepatocytes in vivo.
Fig. 5. Liver sections stained with an antibody to PCNA/cyclin and counter-stained with hematoxylin. Note the increased staining in C/EBP
/ sections. Original
magnification × 157.5.
DISCUSSION
Is Essential for Postnatal Survival
We have
inactivated the C/EBP gene in mice by the introduction of stop
codons downstream of the two AUG translation start sites used in the
C/EBP gene. These stop codons are situated within the
neoR gene sequence that was inserted in the opposite
direction to the C/EBP transcription unit. Thus, this manipulation
will not result in a gene inactivation at the transcriptional level but
rather at the translational level. This targeting strategy has enabled
us to obtain new information about the mechanisms of transcription of
the C/EBP gene. First, both alleles of the C/EBP are actively
transcribed since two transcripts of different sizes are detected in
heterozygote animals. Thus, we conclude that the C/EBP gene is not
imprinted in mice. Second, the presence of a C/EBP:NeoR fusion
transcript in the nullizygous liver indicates that the previously
suggested autoregulatory mechanism of the C/EBP gene can be
substituted by other C/EBP members. It is likely that C/EBP is
responsible, since this C/EBP family member has been shown to
transactivate C/EBP promoter-reporter constructs in vitro
(22) and is expressed at high levels in nullizygous liver (Fig. 2). The
steady state level of the C/EBP:NeoR fusion transcript is lower
compared with the C/EBP wild type transcript in heterozygote liver.
This may be due to a less efficient transcription of the mutated allele
or the fusion transcript is more unstable. Alternatively, C/EBP may
not be required for its own expression, but rather it may augment
transcription from its own promoter through interactions with other
transcription factors, as suggested for the human gene (23). C/EBP
deficiency may result in lower levels of C/EBP gene expression.
Mice nullizygous for C/EBP are born to term. We have not found any
significant deviation from the expected Mendelian ratio of nullizygous
mice in the litters. This is different compared with a recent report
(1). Perhaps this reflects the different genetic background of the back
crossings of the two nullizygous mutants. Another remote possibility is
that in the study of Wang et al. (1) C/EBP gene
inactivation was accomplished by the deletion of the entire C/EBP
coding region plus 2.4 kb of upstream sequences. This deletion could in
turn have affected important regulatory elements associated with other
genes important for embryogenesis, particularly since a strong DNase
I-hypersensitive site is located in this region (20).
The effects of the C/EBPa gene
inactivation are dramatic but are not manifested until after birth,
when metabolic functions characteristic for the differentiated liver
are initiated in the newborn animal. C/EBP nullizygous mice begin to
runt and die shortly after birth. About 20% of the mutant mice die
consistently at birth or within 30 min postpartum while the rest
survive only for a period of 7-10 h. All mice show gross liver
histologic abnormalities and hypoglycemia and failure to accumulate
lipids or fat. The drastically reduced amounts of stored glycogen and
fat in liver and adipose tissues observed in newborn nullizygous mice
are highly likely to be an important reason for the weakness of these
animals and is probably the reason for the lower body weight at birth.
Stored energy fuels, which are normally built up prior to birth in
liver and adipose tissues, are very important glucose sources for the
newborn animal before the suckling period. Furthermore, the ability to
realize gluconeogenesis is necessary for maintaining energy
homeostasis. Genes coding for PEPCK, glucose-6-phosphatase, and
tyrosine aminotransferase, all highly expressed in liver, are crucial
for gluconeogenesis. We have found that the transcription rate of the
PEPCK gene, a known C/EBP target gene, is reduced to approximately
30% in C/EBP / liver (data not shown). Thus, inadequate
gluconeogenesis is likely to be another reason for the rapidly
appearing low blood glucose levels in C/EBP / mice. This
hypothesis is further substantiated by the fact that another gene
involved in the reversible gluconeogenic/glycolytic pathways, aldolase
B, displays a transcription rate in C/EBP / liver that is only
about 30% of the rate found in +/+ and +/ liver (data not shown).
Interestingly, aldolase B has recently been shown to be a target gene
for C/EBP (34). The maternal glucose in the blood of the newborn
C/EBP / animals is likely consumed very rapidly, since we detect
very low blood glucose levels in these mice already 1-h postpartum. The
apparent lack of energy makes the nullizygous mice so weak that they
very often are unable to start suckling. Even individuals that are able
to start some feeding do not generally survive for any longer periods.
This might indicate metabolic dysfunctions other than storage of energy
fuels and gluconeogenesis. It has been suggested that severe
hypoglycemia is the primary reason for death (1). However, glucose
injections cannot rescue the mutant mice for more than a couple of days
(1). Problems with absorption of nutrients do not appear to be likely,
because histology of the gut does not reveal any
abnormalities,3 a view that is supported by
a previous analysis (1). Thus, the exact mechanisms underlying the
death of C/EBP / animals is not completely clear.
The fact that triacylglycerol stores are not found in either liver or
in adipose tissue suggests that genes important for lipid accumulation,
expressed in both these tissues, may be the targets of C/EBP
regulation. We envisaged that the identification of such target genes
regulated by C/EBP will reveal the mechanisms of action of this
molecule in lipid storage.
The effects of C/EBP gene inactivation are pleiotropic. As mentioned
under ``Results,'' in very rare cases C/EBP / animals are able
to survive for longer periods of up to 4 weeks. These mice will be the
subject for further analysis, enabling studies of the effects of the
C/EBP gene inactivation in later stages of mouse development. For
instance, the brain would be a tissue of interest since C/EBP
expression has been shown to appear first a few weeks postpartum (14,
58) and the Aplysia C/EBP has been implicated in long term
potentiation of neurons (59). In addition, it has been postulated that
C/EBP may play a role in keratinocyte development (13). The long
term C/EBP / survivors may provide some information on this
aspect since the few individuals that survived that long appear to have
skin problems.
The C/EBP nullizygous mice
also differ from their littermates in that they exhibit retarded
pulmonary development. In particular, hyperproliferation of type II
pneumocytes is clearly visible in neonatal lungs. About 20% of the
C/EBP nullizygous mice die within 20-30 min after birth, apparently
from respiratory failure. However, all nullizygous animals showed
histologic evidence of delayed maturation of type II epithelial cells.
This phenotype is analogous to the pulmonary effects of targeted
disruption of a homeodomain gene, GSH-4 (60), TGF-3, and GM-CSF
nullizygous mice (52, 53). Recent evidence suggested a role for
C/EBP in the development and maintenance of the surfactant system in
lung type II cells (15). Nonetheless, since both C/EBP and C/EBP
are expressed in the lung, it is possible that these proteins
compensate for the loss of C/EBP in proper regulation of surfactant
protein genes in lung epithelial cells. By contrast, deficiency of
lipid production in alveoli, due to the absence of C/EBP, may
interfere with inadequate production of functional surfactant
molecules. This could contribute to the respiratory problems associated
with the nullizygous mice and may be the primary reason for the cause
of the immediate death observed in C/EBP / animals of the BAD
type.
/ Mice
Earlier
experiments suggested that the C/EBP gene product may be a component
of the balance between proliferation and differentiation (24, 40, 41, 42).
The loss of C/EBP results in a dramatic induction of
c-myc, c-jun, and -actin RNA in the liver.
These genes correlate well with active cellular proliferation.
Histology of the liver shows that hepatocytes in the nullizygous mice
appear healthy with smaller cytoplasm/nuclei ratio. The morphology of
the / liver is indicative of either regenerating liver or
pseudoglandular hepatocellular carcinoma. PCNA/cyclin immunostaining
experiments that demonstrate excessive accumulation of PCNA/cyclin in
C/EBP / hepatocytes further support the notion that a
substantial portion of the nullizygous hepatocytes are in the
G1/S phase of the cell cycle. Taken together these data
suggest a role for C/EBP as ``orthogene'' necessary for
acquisition and maintenance of the differentiated hepatocyte phenotype.
However, heterozygous mutants do not show, so far, any evidence of
hepatocellular carcinoma formation. It is clear that some of the
activities of the C/EBP gene are compensated for by other members of
the C/EBP family (i.e. as is the case of activation of
C/EBP gene promoter). However, the severity of the C/EBP /
phenotype certainly suggests that this protein is indispensable for
many other critical functions. The availability of this mutant and
eventually a tissue-specific C/EBP knockout line will greatly
facilitate our understanding of the function of this critical molecule
in vivo.
FOOTNOTES
¶ To whom correspondence should be addressed. Tel.: 301-435-2831; Fax: 301-496-7184; E-mail: kgx{at}nchgr.nih.gov.
1 The abbreviations used are: C/EBP, CCAAT/enhancer binding protein; BAD, born almost dead; neoR, neomycin phosphotransferase; PCNA, proliferating cell nuclear antigen; PEPCK, phosphoenolpyruvate carboxykinase; TK, thymidine kinase; bZIP, basic leucine zipper class; bp, base pair; kb, kilobase pair; MOPS, 4-morpholinepropanesulfonic acid.
2 J. Whitshett, personal communication.
3 P. Flodby and K. G. Xanthopoulos, unpublished data.
Acknowledgments
We thank Irma Jansson for culturing and transfecting ES cells. We also thank José Inzunza for excellent technical assistance and contribution at the early stages of this work. Dr. Andras Nagy is acknowledged for the R1 ES cell line. Drs. Mark Brantly, David Kleiner, Sylvia Fojo, and Melissa Rosenfeld have provided expert advice and critical input.
REFERENCES
-
Wang, N.,
Finegold, M. J.,
Bradley, A.,
Ou, C. N.,
Abdelsayed, S. V.,
Wilde, M. D.,
Taylor, L. R.,
Wilson, D. R.,
Darlington, G. J.
(1995)
Science
269,
1108-1112
[Abstract/Free Full Text] -
Johnson, P. F.,
Landschulz, W. H.,
Graves, B. J.,
McKnight, S. L.
(1987)
Genes Dev.
1,
133-146
[Abstract/Free Full Text] -
Grayson, D. R.,
Costa, R. H.,
Xanthopoulos, K. G.,
Darnell, J. E.
(1988)
Science
239,
786-788
[Abstract/Free Full Text] -
Landschulz, W. H.,
Johnson, P. F.,
Adashi, E. Y.,
Graves, B. J.,
McKnight, S. L.
(1988)
Genes Dev.
2,
786-800
[Abstract/Free Full Text] -
Landschulz, W. H.,
Johnson, P. F.,
McKnight, S. L.
(1988)
Science
240,
1759-1764
[Abstract/Free Full Text] - Johnson, P. F. (1990) Cell Growth & Differ. 1, 47-51 [Medline] [Order article via Infotrieve]
- Xanthopoulos, K. G., Mirkovitch, J. (1993) Eur. J. Biochem. 216, 353-360 [Medline] [Order article via Infotrieve]
-
Williams, S. C.,
Cantwell, C. A.,
Johnson, P. F.
(1991)
Genes Dev.
5,
1553-1567
[Abstract/Free Full Text] -
Friedman, A. D.,
McKnight, S. L.
(1990)
Genes Dev.
4,
1416-1426
[Abstract/Free Full Text] -
Pei, D.,
Shih, C.
(1991)
Mol. Cell. Biol.
11,
1480-1487
[Abstract/Free Full Text] -
Nerlov, C.,
Ziff, E. B.
(1994)
Genes Dev.
8,
350-362
[Abstract/Free Full Text] -
Hendricks-Taylor, L. R.,
Darlington, G. J.
(1995)
Nucleic Acids Res.
23,
4726-4733
[Abstract/Free Full Text] -
Birkenmeier, E. H.,
Gwynn, B.,
Howard, S.,
Jerry, J.,
Gordon, J. I.,
Landschulz, W. H.,
McKnight, S. L.
(1989)
Genes Dev.
3,
1146-1156
[Abstract/Free Full Text] -
Xanthopoulos, K. G.,
Mirkovitch, J.,
Decker, T.,
Kuo, C. F.,
Darnell, J. E., Jr.
(1989)
Proc. Natl. Acad. Sci. U. S. A.
86,
4117-4121
[Abstract/Free Full Text] - Li, F., Rosenberg, E., Smith, C. I., Notarfrancesco, K., Reisher, S. R., Shuman, H., Feinstein, S. I. (1995) Am. J. Physiol. 13, 241-247
-
Chandrasekaran, C.,
Gordon, J. I.
(1993)
Proc. Natl. Acad. Sci. U. S. A.
90,
8871-8875
[Abstract/Free Full Text] -
Piontkewitz, Y.,
Enerbäck, S.,
Hedin, L.
(1993)
Endocrinology
133,
2327-2333
[Abstract/Free Full Text] -
Scott, L. M.,
Civin, C. I.,
Rorth, P.,
Friedman, A. D.
(1992)
Blood
80,
1725-1735
[Abstract/Free Full Text] - Antonson, P., Xanthopoulos, K. G. (1995) Biochem. Biophys. Res. Commun. 215, 106-113 [CrossRef][Medline] [Order article via Infotrieve]
- Xanthopoulos, K. G., Cannon, P. D., Robinson, G. S., Darnell, J. E., Jr. (1992) Eur. J. Biochem. 208, 501-509 [Medline] [Order article via Infotrieve]
-
Christy, R. J.,
Kaestner, K. H.,
Geiman, D. E.,
Lane, M. D.
(1991)
Proc. Natl. Acad. Sci. U. S. A.
88,
2593-2597
[Abstract/Free Full Text] -
Legraverend, C.,
Antonson, P.,
Flodby, P.,
Xanthopoulos, K. G.
(1993)
Nucleic Acids Res.
21,
1735-1742
[Abstract/Free Full Text] - Timchenko, N., Wilson, D. R., Taylor, L. R., Abdelsayed, S., Wilde, M., Sawadogo, M., Darlington, G. J. (1995) Mol. Cell. Biol. 15, 1192-1202 [Abstract]
-
Freytag, S. O.,
Geddes, T. J.
(1992)
Science
256,
379-382
[Abstract/Free Full Text] - Li, L., Nerlov, C., Prendergast, G., MacGregor, D., Ziff, E. (1994) EMBO J. 13, 4070-4079 [Medline] [Order article via Infotrieve]
- Antonson, P., Pray, M. G., Jacobsson, A., Xanthopoulos, K. G. (1995) Eur. J. Biochem. 232, 397-403 [Medline] [Order article via Infotrieve]
-
Friedman, A. D.,
Landschulz, W. H.,
McKnight, S. L.
(1989)
Genes Dev.
3,
1314-1322
[Abstract/Free Full Text] -
Costa, R. H.,
Grayson, D. R.,
Xanthopoulos, K. G.,
Darnell, J. E., Jr.
(1988)
Proc. Natl. Acad. Sci. U. S. A.
85,
3840-3844
[Abstract/Free Full Text] - Yubero, P., Manchado, C., Cassard-Doulcier, A. M., Hampel, T., Viflas, O., Inglesias, R., Giralt, M., Villarroya, F. (1994) Biochem. Biophys. Res. Commun. 198, 653-659 [CrossRef][Medline] [Order article via Infotrieve]
-
Christy, R. J.,
Yang, V. W.,
Ntambi, J. M.,
Geiman, D. E.,
Landschulz, W. H.,
Friedman, A. D.,
Nakabeppu, Y.,
Kelly, T. J.,
Lane, M. D.
(1989)
Genes Dev.
3,
1323-1335
[Abstract/Free Full Text] -
Herrera, R.,
Ro, H. S.,
Robinson, G. S.,
Xanthopoulos, K. G.,
Spiegelman, B. M.
(1989)
Mol. Cell. Biol.
9,
5331-5339
[Abstract/Free Full Text] -
Kaestner, K. H.,
Christy, R. J.,
Lane, M. D.
(1990)
Proc. Natl. Acad. Sci. U. S. A.
87,
251-255
[Abstract/Free Full Text] -
Park, E. A.,
Roesler, W. J.,
Liu, J.,
Klemm, D. J.,
Gurney, A. L.,
Thatcher, J. D.,
Shuman, J.,
Friedman, A.,
Hanson, R. W.
(1990)
Mol. Cell. Biol.
10,
6264-6272
[Abstract/Free Full Text] - Vallet, V., Bens, M., Antoine, B., Levrat, F., Miquerol, L., Kahn, A., Vandewalle, A. (1995) Exp. Cell Res. 216, 363-370 [CrossRef][Medline] [Order article via Infotrieve]
-
Tae, H.-J.,
Luo, X,
Kim, K.-H.
(1994)
J. Biol. Chem.
269,
10475-10484
[Abstract/Free Full Text] - Samuelsson, L., Strömberg, K., Vikman, K., Bjursell, G., Enerbäck, S. (1991) EMBO J. 10, 3787-3793 [Medline] [Order article via Infotrieve]
-
Lin, F. T.,
Lane, D. M.
(1992)
Genes Dev.
6,
533-544
[Abstract/Free Full Text] -
Lin, F.-T.,
Lane, M. D.
(1994)
Proc. Natl. Acad. Sci. U. S. A.
91,
8757-8761
[Abstract/Free Full Text] -
Freytag, S. O.,
Paielli, D. L.,
Gilbert, J. D.
(1994)
Genes Dev.
8,
1654-1663
[Abstract/Free Full Text] -
Umek, R. M.,
Friedman, A. D.,
McKnight, S. L.
(1991)
Science
251,
288-292
[Abstract/Free Full Text] -
Mischoulon, D.,
Rana, B.,
Bucher, N. L. R.,
Farmer, S. R.
(1992)
Mol. Cell. Biol.
12,
2553-2560
[Abstract/Free Full Text] - Flodby, P., Antonson, P., Barlow, C., Blanck, A., Porsch-Hällström, I., Xanthopoulos, K. G. (1993) Exp. Cell Res. 208, 248-256 [CrossRef][Medline] [Order article via Infotrieve]
- Thomas, K. R., Capecchi, M. R. (1987) Cell 51, 503-512 [CrossRef][Medline] [Order article via Infotrieve]
- Mansour, S. L., Thomas, K. R., Capecchi, M. R. (1988) Nature 336, 348-352 [CrossRef][Medline] [Order article via Infotrieve]
-
Nagy, A.,
Rossant, J.,
Nagy, R.,
Abramow-Newerly, W.,
Roder, J. C.
(1993)
Proc. Natl. Acad. Sci. U. S. A.
90,
8224-8228
[Abstract/Free Full Text] - Ramirez-Solis, R., Rivera-Perez, J., Wallace, J. D., Wims, M., Zheng, H., Bradley, A. (1992) Anal. Biochem. 201, 331-335 [CrossRef][Medline] [Order article via Infotrieve]
-
Laird, P. W.,
Zijderveld, A.,
Linders, K.,
Rudnicki, M. A.,
Jaenisch, R.,
Berns, A.
(1991)
Nucleic Acids Res.
19,
4293
[Free Full Text] - Hattori, M., Tugores, A., Veloz, L., Karin, M., Brenner, D. A. (1990) DNA Cell Biol. 9, 777-781 [Medline] [Order article via Infotrieve]
-
Ossipow, V.,
Descombes, P.,
Schibler, U.
(1993)
Proc. Natl. Acad. Sci. U. S. A.
90,
8219-8223
[Abstract/Free Full Text] -
Lin, F. T.,
MacDougald, O. A.,
Diehl, A. M.,
Lane, M. D.
(1993)
Proc. Natl. Acad. Sci. U. S. A.
90,
9606-9610
[Abstract/Free Full Text] - Tönjes, R. R., Xanthopoulos, K. G., Darnell, J. E. J., Paul, D. (1992) EMBO J. 11, 127-133 [Medline] [Order article via Infotrieve]
- Kaartinen, V., Voncken, J. W., Shuler, C., Warburton, D., Bu, D., Heisterkamp, N., Groffen, J. (1995) Nat. Genet. 11, 415-421 [CrossRef][Medline] [Order article via Infotrieve]
-
Dranoff, G.,
Crawford, A. D.,
Sadelain, M.,
Ream, B.,
Rashid, A.,
Bronson, R. T.,
Dickersin, G. R.,
Bachurski, C. J.,
Mark, E. L.,
Whitsett, J. A.,
Mulligan, R. C.
(1994)
Science
264,
713-716
[Abstract/Free Full Text] -
Smith, C. I.,
Rosenberg, E.,
Reisher, S. R.,
Li, F.,
Kefalides, P.,
Fisher, A. B.,
Feinstein, S. I.
(1995)
Am. J. Physiol.
269,
L603-L612
[Abstract/Free Full Text] - Flodby, P., Liao, D.-Z, Blanck, A., Xanthopoulos, K. G., Porsch-Hällström, I. (1995) Mol. Carcinogen. 12, 103-109 [Medline] [Order article via Infotrieve]
- Evan, G. I., Littlewood, T. D. (1993) Curr. Opin. Genet. Dev. 3, 44-49 [CrossRef][Medline] [Order article via Infotrieve]
- Maeda, T., Takenaka, K., Adachi, E., Matsumata, T., Shirabe, K., Honda, H., Sugimachi, K., Tsuneyoshi, M. (1995) J. Surg. Oncol. 60, 75-79 [Medline] [Order article via Infotrieve]
- Kuo, C. F., Xanthopoulos, K. G., Darnell, J. E., Jr. (1990) Development 109, 473-481 [Abstract]
- Alberini, C. M., Ghirardi, M., Metz, R., Kandel, E. R. (1994) Cell 76, 1099-1114 [CrossRef][Medline] [Order article via Infotrieve]
- Li, H., Witte, D. P., Branford, W. W., Aronow, B. J., Weinstein, M., Kaur, S., Wert, S., Singh, G., Schreiner, C. M., Whitsett, J. A., Scott, W. J., Potter, S. S. (1994) EMBO J. 13, 2876-2885 [Medline] [Order article via Infotrieve]
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 Y. Maeda, V. Dave, and J. A. Whitsett Transcriptional Control of Lung Morphogenesis Physiol Rev, January 1, 2007; 87(1): 219 - 244. [Abstract] [Full Text] [PDF]
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 H. Yamasaki, A. Sada, T. Iwata, T. Niwa, M. Tomizawa, K. G. Xanthopoulos, T. Koike, and N. Shiojiri Suppression of C/EBP{alpha} expression in periportal hepatoblasts may stimulate biliary cell differentiation through increased Hnf6 and Hnf1b expression Development, November 1, 2006; 133(21): 4233 - 4243. [Abstract] [Full Text] [PDF]
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T. Berg, L. Didon, and M. Nord Ectopic expression of C/EBP{alpha} in the lung epithelium disrupts late lung development Am J Physiol Lung Cell Mol Physiol, October 1, 2006; 291(4): L683 - L693. [Abstract] [Full Text] [PDF]
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L. Qiao, O. A. MacDougald, and J. Shao CCAAT/Enhancer-binding Protein {alpha} Mediates Induction of Hepatic Phosphoenolpyruvate Carboxykinase by p38 Mitogen-activated Protein Kinase J. Biol. Chem., August 25, 2006; 281(34): 24390 - 24397. [Abstract] [Full Text] [PDF]
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Y. Xu, Y. L. Zhou, W. Luo, Q.-S. Zhu, D. Levy, O. A. MacDougald, and M. L. Snead NF-Y and CCAAT/Enhancer-binding Protein {alpha} Synergistically Activate the Mouse Amelogenin Gene J. Biol. Chem., June 9, 2006; 281(23): 16090 - 16098. [Abstract] [Full Text] [PDF]
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 L. Qiao, P. S. MacLean, H. You, J. Schaack, and J. Shao Knocking Down Liver CCAAT/Enhancer-Binding Protein {alpha} by Adenovirus-Transduced Silent Interfering Ribonucleic Acid Improves Hepatic Gluconeogenesis and Lipid Homeostasis in db/db Mice Endocrinology, June 1, 2006; 147(6): 3060 - 3069. [Abstract] [Full Text] [PDF]
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C. Bruley, V. Lyons, A. G. F. Worsley, M. D. Wilde, G. D. Darlington, N. M. Morton, J. R. Seckl, and K. E. Chapman A Novel Promoter for the 11{beta}-Hydroxysteroid Dehydrogenase Type 1 Gene Is Active in Lung and Is C/EBP{alpha} Independent Endocrinology, June 1, 2006; 147(6): 2879 - 2885. [Abstract] [Full Text] [PDF]
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 G.-L. Wang, X. Shi, E. Salisbury, Y. Sun, J. H. Albrecht, R. G. Smith, and N. A. Timchenko Cyclin D3 Maintains Growth-Inhibitory Activity of C/EBP{alpha} by Stabilizing C/EBP{alpha}-cdk2 and C/EBP{alpha}-Brm Complexes. Mol. Cell. Biol., April 1, 2006; 26(7): 2570 - 2582. [Abstract] [Full Text] [PDF]
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 Y. Tada, R. M. Brena, B. Hackanson, C. Morrison, G. A. Otterson, and C. Plass Epigenetic modulation of tumor suppressor CCAAT/enhancer binding protein alpha activity in lung cancer. J Natl Cancer Inst, March 15, 2006; 98(6): 396 - 406. [Abstract] [Full Text] [PDF]
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P. C. Martis, J. A. Whitsett, Y. Xu, A.-K. T. Perl, H. Wan, and M. Ikegami C/EBP{alpha} is required for lung maturation at birth Development, March 15, 2006; 133(6): 1155 - 1164. [Abstract] [Full Text] [PDF]
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B. T. Porse, T. A. Pedersen, M. S. Hasemann, M. B. Schuster, P. Kirstetter, T. Luedde, I. Damgaard, E. Kurz, C. K. Schjerling, and C. Nerlov The Proline-Histidine-Rich CDK2/CDK4 Interaction Region of C/EBP{alpha} Is Dispensable for C/EBP{alpha}-Mediated Growth Regulation In Vivo Mol. Cell. Biol., February 1, 2006; 26(3): 1028 - 1037. [Abstract] [Full Text] [PDF]
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D. S. Basseres, E. Levantini, H. Ji, S. Monti, S. Elf, T. Dayaram, M. Fenyus, O. Kocher, T. Golub, K.-k. Wong, et al. Respiratory Failure Due to Differentiation Arrest and Expansion of Alveolar Cells following Lung-Specific Loss of the Transcription Factor C/EBP{alpha} in Mice Mol. Cell. Biol., February 1, 2006; 26(3): 1109 - 1123. [Abstract] [Full Text] [PDF]
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J. Yang, C. M. Croniger, J. Lekstrom-Himes, P. Zhang, M. Fenyus, D. G. Tenen, G. J. Darlington, and R. W. Hanson Metabolic Response of Mice to a Postnatal Ablation of CCAAT/Enhancer-binding Protein {alpha} J. Biol. Chem., November 18, 2005; 280(46): 38689 - 38699. [Abstract] [Full Text] [PDF]
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N. Di-Poi, B. Desvergne, L. Michalik, and W. Wahli Transcriptional Repression of Peroxisome Proliferator-activated Receptor {beta}/{delta} in Murine Keratinocytes by CCAAT/Enhancer-binding Proteins J. Biol. Chem., November 18, 2005; 280(46): 38700 - 38710. [Abstract] [Full Text] [PDF]
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E. H. Tan, S. C. Hooi, M. Laban, E. Wong, S. Ponniah, A. Wee, and N.-d. Wang CCAAT/Enhancer Binding Protein {alpha} Knock-in Mice Exhibit Early Liver Glycogen Storage and Reduced Susceptibility to Hepatocellular Carcinoma Cancer Res., November 15, 2005; 65(22): 10330 - 10337. [Abstract] [Full Text] [PDF]
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T. Shimokawa and C. Ra C/EBP{alpha} functionally and physically interacts with GABP to activate the human myeloid IgA Fc receptor (Fc{alpha}R, CD89) gene promoter Blood, October 1, 2005; 106(7): 2534 - 2542. [Abstract] [Full Text] [PDF]
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 P. F. Johnson Molecular stop signs: regulation of cell-cycle arrest by C/EBP transcription factors J. Cell Sci., June 15, 2005; 118(12): 2545 - 2555. [Abstract] [Full Text] [PDF]
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T. Ikezoe, S. Gery, D. Yin, J. O'Kelly, L. Binderup, N. Lemp, H. Taguchi, and H. P. Koeffler CCAAT/Enhancer-Binding Protein {delta}: A Molecular Target of 1,25-Dihydroxyvitamin D3 in Androgen-Responsive Prostate Cancer LNCaP Cells Cancer Res., June 1, 2005; 65(11): 4762 - 4768. [Abstract] [Full Text] [PDF]
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 S. Gery, S. Tanosaki, S. Bose, N. Bose, J. Vadgama, and H. P. Koeffler Down-Regulation and Growth Inhibitory Role of C/EBP{alpha} in Breast Cancer Clin. Cancer Res., May 1, 2005; 11(9): 3184 - 3190. [Abstract] [Full Text] [PDF]
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G.-L. Wang and N. A. Timchenko Dephosphorylated C/EBP{alpha} Accelerates Cell Proliferation through Sequestering Retinoblastoma Protein Mol. Cell. Biol., February 15, 2005; 25(4): 1325 - 1338. [Abstract] [Full Text] [PDF]
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J. Lu, K. I. Izvolsky, J. Qian, and W. V. Cardoso Identification of FGF10 Targets in the Embryonic Lung Epithelium during Bud Morphogenesis J. Biol. Chem., February 11, 2005; 280(6): 4834 - 4841. [Abstract] [Full Text] [PDF]
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 H.-L. Fang, M. Abdolalipour, Z. Duanmu, J. R. Smigelski, A. Weckle, T. A. Kocarek, and M. Runge-Morris REGULATION OF GLUCOCORTICOID-INDUCIBLE HYDROXYSTEROID SULFOTRANSFERASE (SULT2A-40/41) GENE TRANSCRIPTION IN PRIMARY CULTURED RAT HEPATOCYTES: ROLE OF CCAAT/ENHANCER-BINDING PROTEIN LIVER-ENRICHED TRANSCRIPTION FACTORS Drug Metab. Dispos., January 1, 2005; 33(1): 147 - 156. [Abstract] [Full Text] [PDF]
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 K. Matsusue, O. Gavrilova, G. Lambert, H. B. Brewer Jr., J. M. Ward, Y. Inoue, D. LeRoith, and F. J. Gonzalez Hepatic CCAAT/Enhancer Binding Protein {alpha} Mediates Induction of Lipogenesis and Regulation of Glucose Homeostasis in Leptin-Deficient Mice Mol. Endocrinol., November 1, 2004; 18(11): 2751 - 2764. [Abstract] [Full Text] [PDF]
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V. Heath, H. C. Suh, M. Holman, K. Renn, J. M. Gooya, S. Parkin, K. D. Klarmann, M. Ortiz, P. Johnson, and J. Keller C/EBP{alpha} deficiency results in hyperproliferation of hematopoietic progenitor cells and disrupts macrophage development in vitro and in vivo Blood, September 15, 2004; 104(6): 1639 - 1647. [Abstract] [Full Text] [PDF]
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 D. Helbling, B. U. Mueller, N. A. Timchenko, A. Hagemeijer, M. Jotterand, S. Meyer-Monard, A. Lister, J. D. Rowley, B. Huegli, M. F. Fey, et al. The leukemic fusion gene AML1-MDS1-EVI1 suppresses CEBPA in acute myeloid leukemia by activation of Calreticulin PNAS, September 7, 2004; 101(36): 13312 - 13317. [Abstract] [Full Text] [PDF]
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B. Halmos, D. S. Basseres, S. Monti, F. D'Alo, T. Dayaram, K. Ferenczi, B. J. Wouters, C. S. Huettner, T. R. Golub, and D. G. Tenen A Transcriptional Profiling Study of CCAAT/Enhancer Binding Protein Targets Identifies Hepatocyte Nuclear Factor 3{beta} as a Novel Tumor Suppressor in Lung Cancer Cancer Res., June 15, 2004; 64(12): 4137 - 4147. [Abstract] [Full Text] [PDF]
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M. P. Holland, S. P. Bliss, K. A. Berghorn, and M. S. Roberson A Role for CCAAT/Enhancer-Binding Protein {beta} in the Basal Regulation of the Distal-Less 3 Gene Promoter in Placental Cells Endocrinology, March 1, 2004; 145(3): 1096 - 1105. [Abstract] [Full Text] [PDF]
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S. C. Land and F. Darakhshan Thymulin evokes IL-6-C/EBP{beta} regenerative repair and TNF-{alpha} silencing during endotoxin exposure in fetal lung explants Am J Physiol Lung Cell Mol Physiol, March 1, 2004; 286(3): L473 - L487. [Abstract] [Full Text] [PDF]
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R. Zheng, A. D. Friedman, M. Levis, L. Li, E. G. Weir, and D. Small Internal tandem duplication mutation of FLT3 blocks myeloid differentiation through suppression of C/EBP{alpha} expression Blood, March 1, 2004; 103(5): 1883 - 1890. [Abstract] [Full Text] [PDF]
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C. Muller, C. F. Calkhoven, X. Sha, and A. Leutz The CCAAT Enhancer-binding Protein {alpha} (C/EBP{alpha}) Requires a SWI/SNF Complex for Proliferation Arrest J. Biol. Chem., February 20, 2004; 279(8): 7353 - 7358. [Abstract] [Full Text] [PDF]
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C. R. Walkley, L. E. Purton, H. J. Snelling, Y.-D. Yuan, H. Nakajima, P. Chambon, R. A. S. Chandraratna, and G. A. McArthur Identification of the molecular requirements for an RAR{alpha}-mediated cell cycle arrest during granulocytic differentiation Blood, February 15, 2004; 103(4): 1286 - 1295. [Abstract] [Full Text] [PDF]
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 F. Zhang, T. Pan, L. D. Nielsen, and R. J. Mason Lipogenesis in Fetal Rat Lung: Importance of C/EBP{alpha}, SREBP-1c, and Stearoyl-CoA Desaturase Am. J. Respir. Cell Mol. Biol., February 1, 2004; 30(2): 174 - 183. [Abstract] [Full Text] [PDF]
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S. E. Ross, H. S. Radomska, B. Wu, P. Zhang, J. N. Winnay, L. Bajnok, W. S. Wright, F. Schaufele, D. G. Tenen, and O. A. MacDougald Phosphorylation of C/EBP{alpha} Inhibits Granulopoiesis Mol. Cell. Biol., January 15, 2004; 24(2): 675 - 686. [Abstract] [Full Text] [PDF]
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J.-W. Zhang, Q.-Q. Tang, C. Vinson, and M. D. Lane Dominant-negative C/EBP disrupts mitotic clonal expansion and differentiation of 3T3-L1 preadipocytes PNAS, January 6, 2004; 101(1): 43 - 47. [Abstract] [Full Text] [PDF]
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A.-M. Barlier-Mur, B. Chailley-Heu, C. Pinteur, A. Henrion-Caude, C. Delacourt, and J. R. Bourbon Maturational Factors Modulate Transcription Factors CCAAT/Enhancer-Binding Proteins {alpha}, {beta}, {delta}, and Peroxisome Proliferator-Activated Receptor-{gamma} in Fetal Rat Lung Epithelial Cells Am. J. Respir. Cell Mol. Biol., November 1, 2003; 29(5): 620 - 626. [Abstract] [Full Text]
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T. N. Cassel and M. Nord C/EBP transcription factors in the lung epithelium Am J Physiol Lung Cell Mol Physiol, October 1, 2003; 285(4): L773 - L781. [Abstract] [Full Text] [PDF]
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M. Shim and R. C. Smart Lithium Stabilizes the CCAAT/Enhancer-binding Protein {alpha} (C/EBP{alpha}) through a Glycogen Synthase Kinase 3 (GSK3)-independent Pathway Involving Direct Inhibition of Proteasomal Activity J. Biol. Chem., May 23, 2003; 278(22): 19674 - 19681. [Abstract] [Full Text] [PDF]
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A. Khanna-Gupta, T. Zibello, H. Sun, P. Gaines, and N. Berliner Chromatin immunoprecipitation (ChIP) studies indicate a role for CCAAT enhancer binding proteins alpha and epsilon (C/EBPalpha and C/EBPepsilon ) and CDP/cut in myeloid maturation-induced lactoferrin gene expression Blood, May 1, 2003; 101(9): 3460 - 3468. [Abstract] [Full Text] [PDF]
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A. F. Gombart, S. H. Kwok, K. L. Anderson, Y. Yamaguchi, B. E. Torbett, and H. P. Koeffler Regulation of neutrophil and eosinophil secondary granule gene expression by transcription factors C/EBPepsilon and PU.1 Blood, April 15, 2003; 101(8): 3265 - 3273. [Abstract] [Full Text] [PDF]
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J. Rangatia, R. K. Vangala, N. Treiber, P. Zhang, H. Radomska, D. G. Tenen, W. Hiddemann, and G. Behre Downregulation of c-Jun Expression by Transcription Factor C/EBP{alpha} Is Critical for Granulocytic Lineage Commitment Mol. Cell. Biol., December 15, 2002; 22(24): 8681 - 8694. [Abstract] [Full Text] [PDF]
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J. Du, M. J. Stankiewicz, Y. Liu, Q. Xi, J. E. Schmitz, J. A. Lekstrom-Himes, and S. J. Ackerman Novel Combinatorial Interactions of GATA-1, PU.1, and C/EBPepsilon Isoforms Regulate Transcription of the Gene Encoding Eosinophil Granule Major Basic Protein J. Biol. Chem., November 1, 2002; 277(45): 43481 - 43494. [Abstract] [Full Text] [PDF]
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T. N. Cassel, T. Berg, G. Suske, and M. Nord Synergistic Transactivation of the Differentiation-dependent Lung Gene Clara Cell Secretory Protein (Secretoglobin 1a1) by the Basic Region Leucine Zipper Factor CCAAT/Enhancer-binding Protein alpha and the Homeodomain Factor Nkx2.1/Thyroid Transcription Factor-1 J. Biol. Chem., September 27, 2002; 277(40): 36970 - 36977. [Abstract] [Full Text] [PDF]
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H. Yamamoto, S. Kurebayashi, T. Hirose, H. Kouhara, and S. Kasayama Reduced IRS-2 and GLUT4 expression in PPAR{gamma}2-induced adipocytes derived from C/EBP{beta} and C/EBP{delta}-deficient mouse embryonic fibroblasts J. Cell Sci., September 15, 2002; 115(18): 3601 - 3607. [Abstract] [Full Text] [PDF]
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C. Gregori, A. Porteu, C. Mitchell, A. Kahn, and A.-L. Pichard In Vivo Functional Characterization of the Aldolase B Gene Enhancer J. Biol. Chem., August 2, 2002; 277(32): 28618 - 28623. [Abstract] [Full Text] [PDF]
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G. Behre, S. M. Singh, H. Liu, L. T. Bortolin, M. Christopeit, H. S. Radomska, J. Rangatia, W. Hiddemann, A. D. Friedman, and D. G. Tenen Ras Signaling Enhances the Activity of C/EBPalpha to Induce Granulocytic Differentiation by Phosphorylation of Serine 248 J. Biol. Chem., July 12, 2002; 277(29): 26293 - 26299. [Abstract] [Full Text] [PDF]
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V. A. Reddy, A. Iwama, G. Iotzova, M. Schulz, A. Elsasser, R. K. Vangala, D. G. Tenen, W. Hiddemann, and G. Behre Granulocyte inducer C/EBPalpha inactivates the myeloid master regulator PU.1: possible role in lineage commitment decisions Blood, June 28, 2002; 100(2): 483 - 490. [Abstract] [Full Text] [PDF]
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M. C. Carmona, R. Iglesias, M.-J. Obregon, G. J. Darlington, F. Villarroya, and M. Giralt Mitochondrial Biogenesis and Thyroid Status Maturation in Brown Fat Require CCAAT/Enhancer-binding Protein alpha J. Biol. Chem., June 7, 2002; 277(24): 21489 - 21498. [Abstract] [Full Text] [PDF]
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Y. He and E. Crouch Surfactant Protein D Gene Regulation. INTERACTIONS AMONG THE CONSERVED CCAAT/ENHANCER-BINDING PROTEIN ELEMENTS J. Biol. Chem., May 24, 2002; 277(22): 19530 - 19537. [Abstract] [Full Text] [PDF]
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A. F. Gombart, W.-K. Hofmann, S. Kawano, S. Takeuchi, U. Krug, S. H. Kwok, R. J. Larsen, H. Asou, C. W. Miller, D. Hoelzer, et al. Mutations in the gene encoding the transcription factor CCAAT/enhancer binding protein alpha in myelodysplastic syndromes and acute myeloid leukemias Blood, February 15, 2002; 99(4): 1332 - 1340. [Abstract] [Full Text] [PDF]
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B. Halmos, C. S. Huettner, O. Kocher, K. Ferenczi, D. D. Karp, and D. G. Tenen Down-Regulation and Antiproliferative Role of C/EBP{alpha} in Lung Cancer Cancer Res., January 1, 2002; 62(2): 528 - 534. [Abstract] [Full Text] [PDF]
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H. G. Linhart, K. Ishimura-Oka, F. DeMayo, T. Kibe, D. Repka, B. Poindexter, R. J. Bick, and G. J. Darlington C/EBPalpha is required for differentiation of white, but not brown, adipose tissue PNAS, October 12, 2001; (2001) 211416898. [Abstract] [Full Text] [PDF]
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F. Schaufele, J. F. Enwright III, X. Wang, C. Teoh, R. Srihari, R. Erickson, O. A. MacDougald, and R. N. Day CCAAT/Enhancer Binding Protein {alpha} Assembles Essential Cooperating Factors in Common Subnuclear Domains Mol. Endocrinol., October 1, 2001; 15(10): 1665 - 1676. [Abstract] [Full Text] [PDF]
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H. Nakajima and J. N. Ihle Granulocyte colony-stimulating factor regulates myeloid differentiation through CCAAT/enhancer-binding protein {epsilon} Blood, August 15, 2001; 98(4): 897 - 905. [Abstract] [Full Text] [PDF]
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L. M. Johansen, A. Iwama, T. A. Lodie, K. Sasaki, D. W. Felsher, T. R. Golub, and D. G. Tenen c-Myc Is a Critical Target for C/EBP{alpha} in Granulopoiesis Mol. Cell. Biol., June 1, 2001; 21(11): 3789 - 3806. [Abstract] [Full Text]
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A. F. Gombart, M. Shiohara, S. H. Kwok, K. Agematsu, A. Komiyama, and H. P. Koeffler Neutrophil-specific granule deficiency: homozygous recessive inheritance of a frameshift mutation in the gene encoding transcription factor CCAAT/enhancer binding protein-{epsilon} Blood, May 1, 2001; 97(9): 2561 - 2567. [Abstract] [Full Text] [PDF]
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S. E. Lyons, B. C. Shue, A. C. Oates, L. I. Zon, and P. P. Liu A novel myeloid-restricted zebrafish CCAAT/enhancer-binding protein with a potent transcriptional activation domain Blood, May 1, 2001; 97(9): 2611 - 2617. [Abstract] [Full Text] [PDF]
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 J. A. Lekstrom-Himes The Role of C/EBP{{varepsilon}} in the Terminal Stages of Granulocyte Differentiation Stem Cells, February 1, 2001; 19(2): 125 - 133. [Abstract] [Full Text]
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 F. T. Kockar, P. Foka, T. R. Hughes, S. Kousteni, and D. P. Ramji Analysis of the Xenopus laevis CCAAT-enhancer binding protein {{alpha}} gene promoter demonstrates species-specific differences in the mechanisms for both auto-activation and regulation by Sp1 Nucleic Acids Res., January 15, 2001; 29(2): 362 - 372. [Abstract] [Full Text] [PDF]
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A. Menendez-Hurtado, A. Santos, and A. Perez-Castillo Characterization of the Promoter Region of the Rat CCAAT/Enhancer-Binding Protein {alpha} Gene and Regulation by Thyroid Hormone in Rat Immortalized Brown Adipocytes Endocrinology, November 1, 2000; 141(11): 4164 - 4170. [Abstract] [Full Text] [PDF]
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A. Heydemann, S. Warming, C. Clendenin, K. Sigrist, J. P. Hjorth, and M. C. Simon A minimal c-fes cassette directs myeloid-specific expression in transgenic mice Blood, November 1, 2000; 96(9): 3040 - 3048. [Abstract] [Full Text] [PDF]
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 C. F. Calkhoven, C. Müller, and A. Leutz Translational control of C/EBPalpha and C/EBPbeta isoform expression Genes & Dev., August 1, 2000; 14(15): 1920 - 1932. [Abstract] [Full Text]
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E. D. Rosen, C. J. Walkey, P. Puigserver, and B. M. Spiegelman Transcriptional regulation of adipogenesis Genes & Dev., June 1, 2000; 14(11): 1293 - 1307. [Full Text]
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Y. L. Zhou and M. L. Snead Identification of CCAAT/Enhancer-binding Protein alpha as a Transactivator of the Mouse Amelogenin Gene J. Biol. Chem., April 14, 2000; 275(16): 12273 - 12280. [Abstract] [Full Text] [PDF]
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T. N. Cassel, L. Nordlund-Möller, O. Andersson, J.-A. Gustafsson, and M. Nord C/EBPalpha and C/EBPdelta Activate the Clara Cell Secretory Protein Gene through Interaction with Two Adjacent C/EBP-Binding Sites Am. J. Respir. Cell Mol. Biol., April 1, 2000; 22(4): 469 - 480. [Abstract] [Full Text]
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 T. Kaisho, H. Tsutsui, T. Tanaka, T. Tsujimura, K. Takeda, T. Kawai, N. Yoshida, K. Nakanishi, and S. Akira Impairment of Natural Killer Cytotoxic Activity and Interferon {gamma} Production in CCAAT/Enhancer Binding Protein {gamma}-deficient Mice J. Exp. Med., December 6, 1999; 190(11): 1573 - 1582. [Abstract] [Full Text] [PDF]
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J. P. O'Rourke, G. C. Newbound, J. A. Hutt, and J. DeWille CCAAT/Enhancer-binding Protein delta Regulates Mammary Epithelial Cell G0 Growth Arrest and Apoptosis J. Biol. Chem., June 4, 1999; 274(23): 16582 - 16589. [Abstract] [Full Text] [PDF]
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C. Arizmendi, S. Liu, C. Croniger, V. Poli, and J. E. Friedman The Transcription Factor CCAAT/Enhancer-binding Protein beta Regulates Gluconeogenesis and Phosphoenolpyruvate Carboxykinase (GTP) Gene Transcription during Diabetes J. Biol. Chem., May 7, 1999; 274(19): 13033 - 13040. [Abstract] [Full Text] [PDF]
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J. Lekstrom-Himes and K. G. Xanthopoulos CCAAT/Enhancer Binding Protein varepsilon Is Critical for Effective Neutrophil-Mediated Response to Inflammatory Challenge Blood, May 1, 1999; 93(9): 3096 - 3105. [Abstract] [Full Text] [PDF]
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N. A. Timchenko, M. Wilde, and G. J. Darlington C/EBPalpha Regulates Formation of S-Phase-Specific E2F-p107 Complexes in Livers of Newborn Mice Mol. Cell. Biol., April 1, 1999; 19(4): 2936 - 2945. [Abstract] [Full Text] [PDF]
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K. H. Kaestner, J. Katz, Y. Liu, D. J. Drucker, and G. Schütz Inactivation of the winged helix transcription factor HNF3alpha affects glucose homeostasis and islet glucagon gene expression in vivo Genes & Dev., February 15, 1999; 13(4): 495 - 504. [Abstract] [Full Text]
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C. Croniger, P. Leahy, L. Reshef, and R. W. Hanson C/EBP and the Control of Phosphoenolpyruvate Carboxykinase Gene Transcription in the Liver J. Biol. Chem., November 27, 1998; 273(48): 31629 - 31632. [Full Text] [PDF]
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A. M. Diehl Roles of CCAAT/Enhancer-binding Proteins in Regulation of Liver Regenerative Growth J. Biol. Chem., November 20, 1998; 273(47): 30843 - 30846. [Abstract] [Full Text] [PDF]
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G. J. Darlington, S. E. Ross, and O. A. MacDougald The Role of C/EBP Genes in Adipocyte Differentiation J. Biol. Chem., November 13, 1998; 273(46): 30057 - 30060. [Full Text] [PDF]
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V. M. Christoffels, T. Grange, K. H. Kaestner, T. J. Cole, G. J. Darlington, C. M. Croniger, and W. H. Lamers Glucocorticoid Receptor, C/EBP, HNF3, and Protein Kinase A Coordinately Activate the Glucocorticoid Response Unit of the Carbamoylphosphate Synthetase I Gene Mol. Cell. Biol., November 1, 1998; 18(11): 6305 - 6315. [Abstract] [Full Text]
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J. Lekstrom-Himes and K. G. Xanthopoulos Biological Role of the CCAAT/Enhancer-binding Protein Family of Transcription Factors J. Biol. Chem., October 30, 1998; 273(44): 28545 - 28548. [Abstract] [Full Text] [PDF]
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T. Kimura, V. M. Christoffels, S. Chowdhury, K. Iwase, H. Matsuzaki, M. Mori, W. H. Lamers, G. J. Darlington, and M. Takiguchi Hypoglycemia-associated Hyperammonemia Caused by Impaired Expression of Ornithine Cycle Enzyme Genes in C/EBPalpha Knockout Mice J. Biol. Chem., October 16, 1998; 273(42): 27505 - 27510. [Abstract] [Full Text] [PDF]
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P. Zhang, A. Iwama, M. W. Datta, G. J. Darlington, D. C. Link, and D. G. Tenen Upregulation of Interleukin 6 and Granulocyte Colony-Stimulating Factor Receptors by Transcription Factor CCAAT Enhancer Binding Protein alpha (C/EBPalpha ) Is Critical for Granulopoiesis J. Exp. Med., September 21, 1998; 188(6): 1173 - 1184. [Abstract] [Full Text] [PDF]
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M. S. Petrovick, S. W. Hiebert, A. D. Friedman, C. J. Hetherington, D. G. Tenen, and D.-E. Zhang Multiple Functional Domains of AML1: PU.1 and C/EBPalpha Synergize with Different Regions of AML1 Mol. Cell. Biol., July 1, 1998; 18(7): 3915 - 3925. [Abstract] [Full Text]
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H. S. Radomska, C. S. Huettner, P. Zhang, T. Cheng, D. T. Scadden, and D. G. Tenen CCAAT/Enhancer Binding Protein alpha Is a Regulatory Switch Sufficient for Induction of Granulocytic Development from Bipotential Myeloid Progenitors Mol. Cell. Biol., July 1, 1998; 18(7): 4301 - 4314. [Abstract] [Full Text]
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H. H. Cha, E. J. Cram, E. C. Wang, A. J. Huang, H. G. Kasler, and G. L. Firestone Glucocorticoids Stimulate p21 Gene Expression by Targeting Multiple Transcriptional Elements within a Steroid Responsive Region of the p21waf1/cip1 Promoter in Rat Hepatoma Cells J. Biol. Chem., January 23, 1998; 273(4): 1998 - 2007. [Abstract] [Full Text] [PDF]
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E. J. Cram, R. A. Ramos, E. C. Wang, H. H. Cha, Y. Nishio, and G. L. Firestone Role of the CCAAT/Enhancer Binding Protein-alpha Transcription Factor in the Glucocorticoid Stimulation of p21waf1/cip1 Gene Promoter Activity in Growth-arrested Rat Hepatoma Cells J. Biol. Chem., January 23, 1998; 273(4): 2008 - 2014. [Abstract] [Full Text] [PDF]
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D. R. Breed, L. R. Margraf, J. L. Alcorn, and C. R. Mendelson Transcription Factor C/EBP{delta} in Fetal Lung: Developmental Regulation and Effects of Cyclic Adenosine 3',5'-Monophosphate and Glucocorticoids Endocrinology, December 1, 1997; 138(12): 5527 - 5534. [Abstract] [Full Text] [PDF]
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D. G. Tenen, R. Hromas, J. D. Licht, and D.-E. Zhang Transcription Factors, Normal Myeloid Development, and Leukemia Blood, July 15, 1997; 90(2): 489 - 519. [Full Text] [PDF]
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W.-H. Zhang, R. Srihari, R. N. Day, and F. Schaufele CCAAT/Enhancer-binding Protein alpha Alters Histone H3 Acetylation at Large Subnuclear Domains J. Biol. Chem., October 26, 2001; 276(44): 40373 - 40376. [Abstract] [Full Text] [PDF]
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Y. L. Zhou, Y. Lei, and M. L. Snead Functional Antagonism between Msx2 and CCAAT/Enhancer-binding Protein alpha in Regulating the Mouse Amelogenin Gene Expression Is Mediated by Protein-Protein Interaction J. Biol. Chem., September 8, 2000; 275(37): 29066 - 29075. [Abstract] [Full Text] [PDF]
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C. M. Croniger, C. Millward, J. Yang, Y. Kawai, I. J. Arinze, S. Liu, M. Harada-Shiba, K. Chakravarty, J. E. Friedman, V. Poli, et al. Mice with a Deletion in the Gene for CCAAT/Enhancer-binding Protein beta Have an Attenuated Response to cAMP and Impaired Carbohydrate Metabolism J. Biol. Chem., January 5, 2001; 276(1): 629 - 638. [Abstract] [Full Text] [PDF]
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H. G. Linhart, K. Ishimura-Oka, F. DeMayo, T. Kibe, D. Repka, B. Poindexter, R. J. Bick, and G. J. Darlington C/EBPalpha is required for differentiation of white, but not brown, adipose tissue PNAS, October 23, 2001; 98(22): 12532 - 12537. [Abstract] [Full Text] [PDF]
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