| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
J. Biol. Chem., Vol. 278, Issue 26, 24132-24138, June 27, 2003
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
¶ **
From the
Department of Regeneration Medicine,
Institute of Molecular Embryology and Genetics, Kumamoto University, 2-2-1
Honjo, Kumamoto 860-0811, Japan, and the
Division of Gastroenterology, Department of
Internal Medicine, Kyoto University Post Graduate School of Medicine and the
||Department of Cell Biology, Institute for Virus
Research, Kyoto University, Sakyo-ku, Kyoto 606-8507, Japan
Received for publication, March 5, 2003 , and in revised form, April 22, 2003.
 |
ABSTRACT |
|---|
 TOP ABSTRACT INTRODUCTIONEXPERIMENTAL PROCEDURESRESULTSDISCUSSIONREFERENCES |
|---|
|
INTRODUCTION |
|---|
|
TOPABSTRACTINTRODUCTIONEXPERIMENTAL PROCEDURESRESULTSDISCUSSIONREFERENCES |
|---|
Recent studies of cytosine hypomethylation mutants have revealed that both DNA methylation and histone modifications share a common pathway in chromatin organization (8). The Neurospora crassa DIM-5 gene product is a histone H3 methylase containing a SET domain, which specifically methylates lysine 9 of histone H3, abbreviated throughout as H3 (Lys-9). The mutant dim-5 completely abolished cytosine methylation of the genome. Furthermore, Arabidopsis thaliana DDM1, which shows amino acid similarity to a helicase of the SWI2/SNF2 family, is also required for the maintenance of genomic methylation (9), and disruption of the homolog Lsh gene caused demethylation of the mouse genome (10). These suggest that DNA methylation may depend on methyl-H3 (Lys-9) and unique chromatin structure. However, interrelations between cytosine methylation, MBD proteins, and the histone-modifying system remain to be elucidated (1, 3, 11).
MBD1 is known to act as a transcriptional repressor through the cooperation of MBD, cysteine-rich CXXC domains, and a C-terminal transcriptional repression domain (TRD) (12–15). The conserved CXXC sequence was originally found in DNMT1 and the trithorax group protein ALL-1, but its precise role is unknown (12, 15). MBD1 produces an active transcriptional repression that was partially reversed by the addition of histone deacetylase inhibitors (13). During investigation of the mechanism of transcriptional repression by the TRD of MBD1, we have recently found that a transcriptional mediator, MBD1-containing chromatin associated factor (MCAF), binds the TRD of MBD1 to form the repressive complex (16). In addition, the MBD of MBD1 binds a symmetrically methylated CpG sequence (17), but transcriptional roles of this domain have not been investigated. Little is understood about the state of histone modifications within MBD1-containing heterochromatin on methylated gene promoters. In this study, we show that H3 (Lys-9) methylase Suv39h1 and the methyl lysine-binding protein HP1 interact with MBD of MBD1. Suv39h1 enhances MBD1-mediated transcriptional repression via MBD but not the C-terminal TRD of MBD1. Furthermore, MBD1 associates with histone deacetylases through Suv39h1. Our data suggest that MBD1 tethers the Suv39h1-HP1 complex to methylated DNA regions. We discuss the possible pathway from DNA methylation to the modifications of histones for epigenetic gene regulation.
|
EXPERIMENTAL PROCEDURES |
|---|
|
TOPABSTRACTINTRODUCTIONEXPERIMENTAL PROCEDURESRESULTSDISCUSSIONREFERENCES |
|---|
Plasmids—pEGFP-Suv39h1, pEGFP-G9a, pEGFP-MBD1v3, pEGFP-MBD1
(MBD+NLS), pCGN-MBD1v3, pCGN-MBD1v3 
N, pCMV-GAL4-MBD14,
pCMV-GAL4-MBD17, pCMV-GAL4-MBD111, and reporters that contain
GAL4-binding elements upstream of the SNRPN and VHL
promoters were as described
(12,
14,
18). The cDNA for
Suv39h1 was inserted into pcDNA3 (Invitrogen) and pCMV-GAL4 (GAL4
mock). The cDNA for HP1
was inserted into pcDNA3. The cDNA for
MBD1v3 was ligated into pcDNA3 and pDsRed-N1 (Clontech).
Chemical Cross-linking and Chromatin Immunoprecipitation Assay
(ChIP)—Cells (5 x 105) were treated for 30 min on
ice with dimethyl 3,3'-dithiobispropionimidate-2HCl (DTBP) (5
mM) (Pierce) in phosphate-buffered saline and then with the
addition of 1% formaldehyde for 10 min. Crude cell lysates were sonicated to
generate DNA fragments 200–1000 bp in length. Chromatin
immunoprecipitation was performed with anti-FLAG, anti-HP1, and
anti-Pol II antibodies or control IgG. Specific sequences for the p16
gene promoter in the immunoprecipitates were detected by PCR amplification
with the p16-W primers
(14).
Protein Expression—The full-length (amino acids 1–605)
sequence and the MBD (1–84), CXXC1 (174–220),
CXXC2 (221–327), CXXC3 (328–379), and TRD
(529–592) of MBD1v1 cDNA were cloned into pGEX-4T-1 (Amersham
Biosciences). The full-length (1–412) sequence and 1
(1–88), 2 (89–254), and 3 (255–412) of Suv39h1
were also inserted to pGEX-4T-1. The full-length cDNA for HP1
(1–191) was cloned into pRSET (Invitrogen).
In Vitro Translation and Glutathione S-Transferase (GST) Pull-down—Plasmid DNA (1 µg) was used for in vitro transcription and translation (50 µl) according to the manufacturer (Promega). Bacterially expressed GST and GST-fused proteins (2 µg) were immobilized on glutathione-agarose beads and incubated with either whole lysates from HeLa cells, in vitro translated proteins, or His-tagged proteins (2 µg) in a buffer (250 µl) containing 0.1% TritonX-100, 50 mM HEPES, pH 7.4, 50–300 mM NaCl, 5% glycerol, 2 mM dithiothreitol, and protease inhibitors for1hat4 °C. The input indicates 5% of HeLa cell lysates, in vitro translated and His-tagged proteins, in the reaction mixture.
Immunoprecipitation—HeLa cell lysates were incubated with
specific antibodies or control IgG (Santa Cruz Biotechnology) for 1 h at 4
°C. This was followed by incubation for 1 h after adding 30 µl of
protein G/A agarose beads (Oncogene) in a buffer (250 µl) containing 0.2%
Nonidet P-40, 40 mM Tris-HCl, pH 7.5, 100 mM KCl, 20%
glycerol, and protease inhibitors. The immunoprecipitations of endogenous
methyl-H3 (lysine 9) and FLAG-MBD1 and endogenous MBD1 and HP1 in HeLa
cells were performed after cross-linking with DTBP. The input indicates 5% of
HeLa cell lysates.
Antibodies, Western Blot, and Immunofluorescence
Analyses—Polyclonal antibodies against HP1 (amino acids
1–191) were generated by immunizing rats against the His-tagged
HP1. For affinity purification of the antibodies, GST-fused HP1
(1–191) was coupled to an Affi-Gel activated matrix (Bio-Rad). Anti-MBD1
antibodies were generated previously
(16) or purchased from Santa
Cruz Biotechnology. Antibodies utilized were anti-histone deacetylase 1
(anti-HDAC1; H-51), anti-HDAC2 (C-8), anti-RNA polymerase II (Santa Cruz
Biotechnology), anti-FLAG (M5) (Sigma), anti-His (Qiagen), anti-hemagglutinin
1 (HA) (Roche Applied Science), and anti-dimethyl-histone H3 (lysine 9)
antibodies (Upstate Biotechnology). Western blot and immunofluorescence
analyses were carried out as described
(12).
|
RESULTS |
|---|
|
TOPABSTRACTINTRODUCTIONEXPERIMENTAL PROCEDURESRESULTSDISCUSSIONREFERENCES |
|---|
in the
Nucleus—To address the mechanism(s) of transcriptional repression
by MBD1, we considered whether MBD1 can associate with histone methylases such
as Suv39h1 and G9a by using an immunofluorescence analysis in HeLa cells
(Fig. 1). Previous reports
clarified that the subnuclear localization of MBD1 depends on the genome
methylation (12,
14). Fluorescent protein-fused
Suv39h1 and MBD1 showed a similar punctate distribution with multiple foci in
the nuclei except for nucleolus (Fig.
1A). In contrast, MBD1 did not preferably colocalize with
G9a (Fig. 1B),
emphasizing the specific correlation between MBD1 and Suv39h1. As previous
reports demonstrated that Suv39h1 associates with HP1
(19,
20), MBD1 was also found to
mostly coexist with HP1 (Fig.
1C). Because Suv39h1 selectively methylates H3 (Lys-9),
we further observed the existence of methyl-H3 (Lys-9) and MBD1 in the
nucleus. The methyl-H3 (Lys-9) proteins concentrated on multiple foci with
intense staining of MBD1 (data not shown). Almost all the nuclei observed
exhibited the patterns shown here. The observation suggested that MBD1
associates with Suv39h1-HP1 on both methyl-H3 (Lys-9) and methylated
DNA-containing regions.
|
To investigate the localization of these proteins on chromosomal gene
promoters, we chose the p16 tumor suppressor gene in which
hypermethylation of the promoter-associated CpG island associates with
transcriptional repression in many cancers
(21,
22). NCI-H1299 cells possessed
a methylated p16 promoter; meanwhile, the same DNA region was
unmethylated in SBC-5 cells
(14,
16). After the cells
expressing FLAG-tagged MBD1 or Suv39h1 were cross-linked with dimethyl
3,3'-dithiobispropionimidate-2HCl and formaldehyde, the coprecipitated
DNAs with appropriate antibodies were subjected to PCR-amplification using a
set of primers for p16 promoter sequences
(Fig. 1D). MBD1 and
Suv39h1 were present on the methylated but not the unmethylated p16
promoter. Using the untransfected cells, HP1 was also found in the
methylated promoter. In contrast, RNA polymerase II-containing complexes
associated exclusively with the unmethylated p16 promoter in SBC-5
cells. These results suggested that MBD1 coexists with the Suv39h1-HP1
heterochromatic complex and may tether it to methylated DNA regions for
establishing histone methylation.
MBD1 Interacts with Suv39h1-HP1 Complex via
MBD—To address the molecular interaction between MBD1 and the
Suv39h1-HP1 complex, we performed an immunoprecipitation analysis in HeLa
cells (Fig. 2A).
FLAG-Suv39h1 was detected in the immunoprecipitates with HA-fused MBD1.
Likewise, MBD1 was present in the Suv39h1-immunoprecipitates. To identify the
direct interaction between MBD1 and Suv39h1, in vitro pull-down
analysis was carried out (Fig.
2B). GST and GST-fused portions of MBD1 were immobilized
on glutathione-agarose beads and incubated with in vitro translated
FLAG-Suv39h1. Full-length MBD1 bound Suv39h1. Interestingly, Suv39h1 was found
to selectively bind the MBD but not the cysteine-rich CXXC domains or
the C-terminal TRD of the MBD1 protein. In agreement with this data, an
immunoprecipitation analysis showed that the HA-N MBD1 mutant, which
was deleted for N-terminal MBD (amino acids 1–61), lost the binding
ability to FLAG-Suv39h1 (Fig.
2C).
|
To map the region of Suv39h1 that interacts with MBD1, GST-fused portions
of Suv39h1 were utilized for a pull-down analysis of in vitro
translated FLAG-MBD1 (Fig.
2D). MBD1 associated with a middle part of Suv39h1
(2), termed the PreSET region, which is located between the chromo
domain (1) and the C-terminal SET catalytic domain (3). This
result indicated the presence of an MBD1-interacting domain in Suv39h1. Next,
we investigated whether HP1 participates in the MBD1-containing
complex, using an immunoprecipitation analysis
(Fig. 2E). Endogenous
HP1 was found in the immunoprecipitates with FLAG-MBD1, and MBD1 was
present in the HP1-immunoprecipitates. To evaluate the direct
interaction of MBD1 with HP1, bacterially expressed proteins were used
for in vitro pull-down analysis
(Fig. 2F). GST-fused
Suv39h1 or parts of MBD1 on glutathione-agarose beads were incubated with
His-tagged HP1. Both full-length Suv39h1 and MBD1 complexed with
HP1. Significantly, the MBD of MBD1, but not the CXXC domains
or TRD, bound HP1. Thus, the data in
Fig. 2, B, C, and
F evidently suggested that MBD is an interacting surface
to Suv39h1-HP1. We further examined the association of these endogenous
proteins in HeLa cells without any overexpression
(Fig. 2G). The band
that reacted to anti-HP1 antibodies was concentrated in the MBD1
immunoprecipitates. Endogenous MBD1 and HP1 were also colocalized in
the nucleus, indicating the existence of complexes containing both proteins
in vivo. Because HP1 tethers Suv39h1 to methyl-H3 (Lys-9), we tested
whether MBD1 associates with methyl-H3 (Lys-9) by using immunoprecipitation.
FLAG-MBD1 was detected in the immune complexes with endogenous methyl-H3
(Lys-9), and methyl-H3 (Lys-9) was also present in the MBD1-immunoprecipitates
(data not shown).
To examine whether the MBD in MBD1 tethers the Suv39h1-HP1 complex to
methylated DNA regions in the nucleus, immunofluorescence analyses of
fluorescent protein-fused Suv39h1, HP1, and MBD1 (MBD+NLS), which
includes only the MBD and nuclear localization signal (NLS) of MBD1, as well
as FLAG-N MBD1 were performed in HeLa cells
(Fig. 2H). As
described above, the punctate distribution of MBD1 with multiple foci depends
on the presence of N-terminal MBD in proportion to genome methylation
(12,
14). The MBD1 (MBD+NLS) showed
multiple foci formation in the interphase nuclei and colocalized with both
Suv39h1 and HP1. On the other hand, N MBD1 was found to be
present throughout the nuclei, and both Suv39h1 and HP1 localized into
differently characteristic foci in the nuclei. Ectopic expression of MBD1
(MBD+NLS) altered the localization of Suv39h1 and HP1, suggesting that
MBD of MBD1 is likely to recruit Suv39h1-HP1 complex to methylated DNA sites.
However, our data do not exclude the possibility that Suv39h1-HP1 recruits
MBD1 to H3 (Lys-9)-methylated chromatin.
Suv39h1 Enhances MBD1-dependent Transcriptional
Repression—Throughout our study in vivo, we chose the use
of the splice isoform v3 of MBD1 (shown in
Fig. 3A), because this
isoform most clearly exhibits DNA methylation-dependent gene silencing
(12,
14). The protein structure of
isoforms MBD1v1 and v3 is identical except for the presence of CXXC3
in MBD1v1 (Fig. 2B),
and the CXXC3 itself seems to have some DNA binding activities. We
investigated whether Suv39h1 is involved in MBD1-mediated transcriptional
silencing. As reported previously
(12), the MBD of MBD1
moderately reduced methylated promoter activities, either by promoter
occupation through the contact between MBD and methylated DNA or by
unidentified mechanisms. To avoid the possibility of the promoter occupation,
we utilized GAL4-fused portions of MBD1v3 (MBD17 (MBD, amino acids
1–61), MBD14 (CXXC1 and 2, amino acids 62–327),
and MBD111 (TRD, amino acids 460–523)) and examined their effects
on a Photinus pyralis luciferase reporter that contains five GAL4
binding elements (5x GAL4) just upstream of the human SNRPN
gene promoter in HeLa cells (Fig.
3A). A Western blot analysis showed that GAL4-fused MBD1
proteins were equally expressed in a dose-dependent manner (data not shown).
MBD111 strongly repressed transcription
(Fig. 3A, hatched
bars), whereas MBD17 moderately suppressed promoter activities
(Fig. 3A, gray
bars). In contrast, MBD14 did not repress transcription
(Fig. 3A, black
bars). Very similar results were obtained with another CpG
island-associated promoter from the VHL gene (data not shown). Next,
Suv39h1 is known to function as a transcriptional corepressor
(23,
24). To confirm whether
Suv39h1 affects transcription, we expressed GAL4-fused Suv39h1 in HeLa cells
to test the effect of this protein on 5x GAL4-containing the
SNRPN and VHL promoters
(Fig. 3B). Suv39h1
inhibited both promoter activities in a dose-dependent manner. The efficiency
of repression by Suv39h1 seemed to be similar to that of MBD1 by MBD. The
GAL4-Suv39h1 was also expressed in proportion to the amount of transfected
plasmid (data not shown).
|
Furthermore, we examined whether Suv39h1 can affect transcriptional
repression by MBD1 (Fig.
3C). FLAG-Suv39h1 and GAL4-fused portions of MBD1 were
expressed in HeLa cells together with the 5x GAL4-containing
promoter-driven luciferase vectors. The luciferase activity, in combination
with FLAG mock, was normalized to 100 (Fig.
3C, leftmost bar), and Suv39h1 alone mildly
repressed transcription from both promoters. GAL-fused MBD17 and
MBD111 were appropriately expressed to repress transcription to
60–80%. Importantly, Suv39h1 synergistically enhanced the repression by
MBD17, but not by MBD111, in a dose-dependent manner. No
additive effect of Suv39h1 was found in the expression of GAL4 mock and
MBD14. In addition, the FLAG-Suv39h1 active mutant (H320R)
(25) enhanced repression by
GAL-MBD17 more than was the case with the wild-type Suv39h1 (data not
shown). These data supported the idea that Suv39h1 contributes to
transcriptional repression by MBD1.
MBD1 Links to Histone Deacetylases via Suv39h1—HDAC
inhibitors such as TSA partially relieved the transcriptional repression by
MBD1 (13). In addition, the N
terminus of Suv39h1 was found to physically interact with HDAC1 and HDAC2,
leading to formation of transcriptionally inactive chromatin
(26). Repression by
GAL4-Suv39h1 was partly reversed by the HDAC inhibitors TSA and sodium
n-butyrate (Fig.
4A, hatched and gray bars,
respectively) in comparison with the solvent alone
(Fig. 4A, black
bars). To examine the interaction of MBD1 and Suv39h1 with HDAC1/HDAC2,
in vitro pull-down and subsequent Western blot analyses were carried
out with the indicated antibodies. Suv39h1, MBD, and TRD of MBD1 in a GST
fusion were immobilized on glutathione-agarose beads and incubated with the
cell lysates from HeLa cells. Suv39h1 and MBD of MBD1 bound both endogenous
HDAC1 and HDAC2 (Fig.
4B, top two panels). The association between
MBD1 and HDAC1/HDAC2 appeared to be indirect, because Suv39h1, but not MBD,
bound in vitro translated HA-tagged HDAC1/HDAC2
(Fig. 4B, bottom
two panels). Immunoprecipitation analyses further showed that HDAC1/HDAC2
were present in both FLAG-tagged Suv39h1 and MBD1 immunoprecipitates
(Fig. 4C). In
contrast, the use of N MBD1 and control IgG failed to immunoprecipitate
the HDAC1/HDAC2. Finally, we studied the effect of HDAC inhibitors on
transcriptional repression by MBD and TRD of MBD1
(Fig. 4D). The
repression by MBD was partially reversed by both TSA
(Fig. 4D, hatched
bars) and sodium n-butyrate
(Fig. 4D, gray
bars). In agreement with a recent study conducted under the same
experimental conditions (16),
these inhibitors appeared to have less effect on transcriptional inhibition of
MBD1 by TRD. Collectively, these data suggest that MBD1 promotes both
methylation and deacetylation of histones on methylated genomic regions
through interaction with Suv39h1-HP1 and HDACs.
|
|
DISCUSSION |
|---|
|
TOPABSTRACTINTRODUCTIONEXPERIMENTAL PROCEDURESRESULTSDISCUSSIONREFERENCES |
|---|
interact with MBD1.
Suv39h1 enhanced MBD1-mediated transcriptional repression via MBD but not via
the C-terminal TRD of MBD1. Furthermore, MBD1 associated with histone
deacetylases probably through Suv39h1. Our data suggest the possibility that
MBD1 tethers the Suv39h1-HP1 complex to methylated DNA regions.
Several transcription repression complexes include the deacetylases and
methylases of histone molecules
(1–5,
7,
11). Hypermethylated DNA
usually tends to coexist with hypoacetylated histones and methyl-H3 (Lys-9) on
the heterochromatic regions. In fact, MeCP2 and MBD2 interact with a
co-repressor complex Sin3 containing HDACs. MBD2-MBD3 heterodimer recruits
another multifunctional complex, Mi2-NuRD, which possesses both HDAC and
chromatin-remodeling activities. This combination of Mi2-NuRD and MBD2 may be
synonymous with the originally designated MeCP1 complex. Nevertheless,
trichostatin A has been found to partially relieve transcriptional repression
by MeCP2 and MBD2. Furthermore, the retinoblastoma protein (Rb) represses
E2F-mediated transcription through interaction not only with histone
deacetylases but also with Suv39h1
(27–29).
Recent reports have shown that MeCP2 blocks transcription both by recruiting
HDACs or an unidentified histone methylase at the promoter
(30). Our data demonstrated
that MBD1 represses transcription together with Suv39h1-HP1 complexes.
In agreement with this, both MBD1 and Suv39h1-HP1 are found in the
pericentromeric heterochromatin, which includes H3 (Lys-9) methylation on the
methylated DNA region (1,
14). Although H3 (Lys-9) is
known to be methylated by Suv39h and G9a, certain histone methylases may be
able to methylate the lysine 9. In fact, double knockouts of both Suv39h1 and
h2 in mouse did not reduce the level of overall H3 (Lys-9) methylation
(25). We do not exclude the
possibility that MBD1 can cooperate with other histone methylases and
chromatin regulators.
We have characterized the solution structure of MBD of MBD1 that binds a
symmetrically methylated CpG dinucleotide, resulting in identification of the
amino acid residues important for recognizing a methyl-CpG pair
(12,
17). Our present study,
however, revealed that the MBD of MBD1 also interacts with Suv39h1 and
HP1, leading to the direct link between DNA methylation and histone
methylation. Boeke et al.
(31) showed that the minimal
repression domain of MBD2b, which is another member of MBD-containing family,
overlaps with its MBD and directly binds Sin3A, a component of the HDAC
complexes. The lines of evidence suggest that MBD itself is actively involved
in the interaction with target proteins for transcriptional repression.
Furthermore, MBD1 is likely to establish and/or maintain the repressive state
by recruiting HDAC1/HDAC2 as well as the Suv39h1-HP1 heterochromatin
complex, suggesting that both methylation and deacetylation of histones
coexist in the MBD1-containing chromatin on methylated DNAs. MBD1 would
provide the chance for methylating core histones in the methylated DNA
regions, as some MBD proteins connect cytosine methylation to histone
deacetylation (7,
32–36).
In other words, all cytosine methylation may not be simply downstream of
histone methylation. The localization of Suv39h1, HP1, and HDACs onto
MBD1-containing methylated DNA sites may exemplify the possible presence of a
repression pathway from DNA methylation to these histone modifications in
heterochromatic regions.
|
FOOTNOTES |
|---|
¶ Research Fellow of the Japan Society for the Promotion of Science.
** To whom correspondence should be addressed. Tel.: 81-96-373-6800; Fax: 81-96-373-6804; E-mail: mnakao{at}gpo.kumamoto-u.ac.jp.
1 The abbreviations used are: MBD, methyl-CpG binding domain; TRD,
transcriptional repression domain; TSA, trichostatin A; GST, glutathione
S-transferase; DTBP, dimethyl
3,3'-dithiobispropionimidate-2HCl; HA, hemagglutinin A; NLS, nuclear
localization signal; HDAC, histone deacetylase; EGFP, enhanced green
fluorescent protein.
|
ACKNOWLEDGMENTS |
|---|
|
REFERENCES |
|---|
|
TOPABSTRACTINTRODUCTIONEXPERIMENTAL PROCEDURESRESULTSDISCUSSIONREFERENCES |
|---|
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati What's this?
This article has been cited by other articles:
|
|
 |
|
  A. M. Allan, X. Liang, Y. Luo, C. Pak, X. Li, K. E. Szulwach, D. Chen, P. Jin, and X. Zhao The loss of methyl-CpG binding protein 1 leads to autism-like behavioral deficits Hum. Mol. Genet., July 1, 2008; 17(13): 2047 - 2057. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 K. W. Kohn, M. I. Aladjem, J. N. Weinstein, and Y. Pommier Chromatin Challenges during DNA Replication: A Systems Representation Mol. Biol. Cell, January 1, 2008; 19(1): 1 - 7. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 M. E. Gazzar, B. K. Yoza, J. Y.-Q. Hu, S. L. Cousart, and C. E. McCall Epigenetic Silencing of Tumor Necrosis Factor {alpha} during Endotoxin Tolerance J. Biol. Chem., September 14, 2007; 282(37): 26857 - 26864. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 N. Agarwal, T. Hardt, A. Brero, D. Nowak, U. Rothbauer, A. Becker, H. Leonhardt, and M. C. Cardoso MeCP2 interacts with HP1 and modulates its heterochromatin association during myogenic differentiation Nucleic Acids Res., August 13, 2007; (2007) gkm599v1. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 C. K. Hwang, K. Y. Song, C. S. Kim, H. S. Choi, X.-H. Guo, P.-Y. Law, L.-N. Wei, and H. H. Loh Evidence of Endogenous Mu Opioid Receptor Regulation by Epigenetic Control of the Promoters Mol. Cell. Biol., July 1, 2007; 27(13): 4720 - 4736. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Sakamoto, S. Watanabe, T. Ichimura, M. Kawasuji, H. Koseki, H. Baba, and M. Nakao Overlapping Roles of the Methylated DNA-binding Protein MBD1 and Polycomb Group Proteins in Transcriptional Repression of HOXA Genes and Heterochromatin Foci Formation J. Biol. Chem., June 1, 2007; 282(22): 16391 - 16400. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 S. Kobayakawa, K. Miike, M. Nakao, and K. Abe Dynamic changes in the epigenomic state and nuclear organization of differentiating mouse embryonic stem cells Genes Cells, April 1, 2007; 12(4): 447 - 460. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
Y. Uchimura, T. Ichimura, J. Uwada, T. Tachibana, S. Sugahara, M. Nakao, and H. Saitoh Involvement of SUMO Modification in MBD1- and MCAF1-mediated Heterochromatin Formation J. Biol. Chem., August 11, 2006; 281(32): 23180 - 23190. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Noer, A. L. Sorensen, A. C. Boquest, and P. Collas Stable CpG Hypomethylation of Adipogenic Promoters in Freshly Isolated, Cultured, and Differentiated Mesenchymal Stem Cells from Adipose Tissue Mol. Biol. Cell, August 1, 2006; 17(8): 3543 - 3556. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
A. Tsumura, T. Hayakawa, Y. Kumaki, S.-i. Takebayashi, M. Sakaue, C. Matsuoka, K. Shimotohno, F. Ishikawa, E. Li, H. R. Ueda, et al. Maintenance of self-renewal ability of mouse embryonic stem cells in the absence of DNA methyltransferases Dnmt1, Dnmt3a and Dnmt3b. Genes Cells, July 1, 2006; 11(7): 805 - 814. [Abstract] [Full Text] [PDF]
|
|
|
|
|
|
J. Tomikawa, K. Fukatsu, S. Tanaka, and K. Shiota DNA Methylation-dependent Epigenetic Regulation of Dimethylarginine Dimethylaminohydrolase 2 Gene in Trophoblast Cell Lineage J. Biol. Chem., April 28, 2006; 281(17): 12163 - 12169. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 R. Villa, L. Morey, V. A. Raker, M. Buschbeck, A. Gutierrez, F. De Santis, M. Corsaro, F. Varas, D. Bossi, S. Minucci, et al. The methyl-CpG binding protein MBD1 is required for PML-RAR{alpha} function PNAS, January 31, 2006; 103(5): 1400 - 1405. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 L. Giacinti, P. P. Claudio, M. Lopez, and A. Giordano Epigenetic information and estrogen receptor alpha expression in breast cancer. Oncologist, January 1, 2006; 11(1): 1 - 8. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 H. Nakashima, M. Nakano, R. Ohnishi, Y. Hiraoka, Y. Kaneda, A. Sugino, and H. Masumoto Assembly of additional heterochromatin distinct from centromere-kinetochore chromatin is required for de novo formation of human artificial chromosome J. Cell Sci., December 15, 2005; 118(24): 5885 - 5898. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
 A K E Swales and N Spears Genomic imprinting and reproduction Reproduction, October 1, 2005; 130(4): 389 - 399. [Abstract] [Full Text] [PDF]
|
|
|
|
 |
|
