HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

J. Biol. Chem., Vol. 276, Issue 10, 6897-6900, March 9, 2001

This Article Abstract Full Text (PDF) All Versions of this Article: 276/10/6897    most recent C000870200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sun, R. Articles by Yang, V. W. Search for Related Content PubMed PubMed Citation Articles by Sun, R. Articles by Yang, V. W. Social Bookmarking                      What's this?

ACCELERATED PUBLICATION
Intestinal-enriched Krüppel-like Factor (Krüppel-like Factor 5) Is a Positive Regulator of Cellular Proliferation^*

Ronggai Sun, Xinming Chen, and Vincent W. Yang^§¶

From the Departments of  Medicine and ^§ Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205

Received for publication, December 11, 2000

	ABSTRACT

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS COMPLEMENTARY DISCUSSION REFERENCES

Intestinal-enriched Krüppel-like factor (IKLF or KLF5) belongs to the family of mammalian Krüppel-like transcription factors. Previous studies indicate that expression of IKLF is enriched in the proliferating crypt epithelial cells of the intestinal tract. However, the biological function of IKLF is unknown. In the current study, we have shown that the level of IKLF mRNA was nearly undetectable in serum-deprived NIH3T3 fibroblasts but became acutely and significantly increased upon the addition of fetal bovine serum or the phorbol ester, PMA. This induction required protein synthesis because it was prevented by cycloheximide. Transfection of IKLF into NIH3T3 cells resulted in the formation of foci in a manner similar to that caused by the activated Ha-ras oncogene. Constitutive expression of IKLF in transfected NIH3T3 cells significantly increased the rate of proliferation when compared with cells transfected with an empty vector. The growth of IKLF-transfected cells was no longer inhibited by cell-cell contact or by low serum content. Moreover, these cells proliferated in an anchorage-independent fashion. We conclude that IKLF encodes a delayed early response gene product that positively regulates cellular proliferation and may give rise to a transformed phenotype when overexpressed.

	INTRODUCTION

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS COMPLEMENTARY DISCUSSION REFERENCES

Krüppel is a zinc finger-containing transcription factor that is responsible for segmentation of the Drosophila melanogaster embryo (1). In vertebrates, a large number of proteins have been identified that exhibit homology to Krüppel (2). One prominent example is Sp1 (3), a general transcription factor. Recently, a family of Krüppel-like factors (KLFs)¹ that are highly related to the mammalian Krüppel protein erythroid Krüppel-like factor (EKLF) (4) have been described (2, 5, 6). Many of these proteins were given a numerical designation by the Human Gene Nomenclature Committee (HGNC, Ref. 7), with EKLF designated as KLF1. The genes encoding many KLFs are expressed in a tissue-specific or -selective manner. In addition, evidence suggests that KLFs collectively exert important regulatory functions in diverse biological processes such as growth, development, differentiation, and apoptosis.

One tissue in which a number of KLFs appear to play an important regulatory role is the intestinal epithelium. This tissue is a dynamic system in which proliferation of stem cells located in the crypts is intimately coupled to their differentiation into mature daughter cells once they exit the crypts (8, 9). Expression of the genes encoding two KLFs, gut-enriched Krüppel-like factor (GKLF or KLF4, Ref. 10, 11) and intestinal-enriched Krüppel-like factor (IKLF or KLF5, Refs. 12, 13), is particularly active in the intestinal epithelium. However, their patterns of expression appear to be complementary rather than redundant. Whereas GKLF is primarily expressed in the differentiated epithelial cells, away from the proliferating zone, IKLF is found mainly in the proliferating crypt cell population. The in vivo pattern of GKLF expression is mirrored by its in vitro pattern; it is found mostly in cells that are growth-arrested (10, 14). Moreover, constitutive expression of GKLF leads to the inhibition of DNA synthesis (10, 15). In contrast, the physiological function of IKLF is less clear, although it has been proposed to have an opposing effect to GKLF in regulating epithelial cell differentiation (12).

The present study seeks to characterize the effect of IKLF on cellular proliferation. We demonstrate that expression of IKLF in cultured cells responds transiently and acutely to growth stimuli. In addition, forced expression of IKLF in transfected cells results in an accelerated rate of proliferation and a transformed phenotype as evidenced by formation of foci, loss of contact inhibition, as well as acquisition of serum- and anchorage-independent growth. Our results indicate that IKLF has a proproliferative effect, which lends support to the previous hypothesis that it may counteract the function of GKLF.

	EXPERIMENTAL PROCEDURES

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS COMPLEMENTARY DISCUSSION REFERENCES

Reagents-- Cell culture media and fetal bovine serum (FBS) were purchased from Life Technologies (Gaithersburg, MD) and Hyclone Laboratories (Logan, UT), respectively. Radioisotopes were purchased from PerkinElmer Life Sciences. Phorbol 12-myristate 13-acetate (PMA) and cycloheximide (CHX) were purchased from Sigma. The monoclonal antibody directed against the hemagglutinin A (HA) epitope (F-7, sc-7392) was purchased from Santa Cruz Biotechnology (Santa Cruz, CA). Expression constructs containing full-length IKLF and HA-tagged IKLF (pBK-CMV-IKLF and pBK-CMV-IKLF·HA, respectively) were kindly provided by Dr. Jerry Lingrel (12). The expression construct containing activated Ha-Ras was a generous gift of Dr. Raul Urrutia (16). The expression construct containing full-length GKLF, PMT3-GKLF, was previously described (10).

Cell Culture-- NIH3T3 cells were maintained in Dulbecco's modified Eagle's medium (DMEM) supplemented with 10% FBS, 100 µg/ml streptomycin, and 100 units/ml penicillin at 37 °C in a 5% CO₂ atmosphere. For experiments involving mitogenic stimulation, cells were first rendered quiescent by removal of serum from the medium for 24 h. Cells were then stimulated with fresh medium containing 15% FBS or 100 ng/ml PMA for various duration. In experiments in which CHX was included, quiescent cells were pretreated with 10 µg/ml CHX for 1 h before the addition of FBS or PMA. Treatments were then continued for another 1 h with the respective mitogen and CHX.

Northern and Western Blot Analyses-- RNA was isolated using the Trizol method (Life Technologies) and resolved by denaturing agarose gel electrophoresis followed by transfer to nylon membranes. Complementary DNA probes encoding IKLF and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) were labeled using [-³²P]dATP and the random-primed DNA labeling kit (Roche Molecular Biochemicals). Conditions of hybridization and washing were previously described (10). Western blot analysis was performed according to a previous protocol (10) using proteins extracted from stably transfected cells. The blots were probed with a monoclonal antibody directed against the HA epitope at a concentration of 200 ng/ml. Blots were then incubated with a peroxidase-conjugated goat anti-mouse IgG (Santa Cruz Biotechnology) at a dilution of 1:2,000. Signals were detected using enhanced chemiluminescence (Amersham Pharmacia Biotech).

Focus Formation Assay-- Focus formation assays were performed according to a previously published protocol (17). Briefly, 5 µg of plasmid DNA containing the various effectors was transfected into NIH3T3 cells using LipofectAMINE (Life Technologies, Inc.). Cells were then maintained in DMEM and 10% FBS for 2-3 weeks at which time they were stained with methylene blue to demonstrate the foci. The number of foci in each dish was then manually counted.

Establishment of Stable IKLF-expressing Cell Lines-- NIH3T3 cells were transfected with pBK-CMV-IKLF·HA or the pBK-CMV empty vector using LipofectAMINE. Two mg/ml G418 was added to the medium beginning 24 h after transfection to select for resistant clones, which were isolated 2 weeks later and expanded. The presence of HA-tagged IKLF was detected by Western blot analysis using the anti-HA monoclonal antibody.

Cell Proliferation and Serum and Anchorage Dependence Assays-- Cell proliferation assays were performed by seeding the IKLF·HA- or empty vector-transfected cells at a density of 2 × 10⁵ cells per well in 6-well plates. Cells were fed DMEM with 10% FBS every other day, and the number of cells in the wells were manually counted with a hemocytometer daily for up to 5 days following seeding. For the serum dependence assay, cells were seeded at a density 2 × 10⁵ cells per well in 6-well plates and maintained in DMEM with 1% FBS. Cells were counted every other day up to 6 days after seeding. Anchorage dependence assay was performed according to a published protocol (17). Ha-ras-, IKLF·HA-, or empty vector-transfected cells were seeded at a density of 5 × 10⁵ cells per 10-cm dish in a 0.33% top agar suspension, which was overlaid onto a 0.5% agar bottom layer. Cells were fed DMEM, 10% FBS, and 2 mg/ml G418 every other day. Colonies developed in the agar suspension were examined 3 weeks following seeding, and the number was tabulated under an inverted phase-contrast microscope. Photodocumentation was accomplished with a Nikon digital camera.

	RESULTS

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS COMPLEMENTARY DISCUSSION REFERENCES

IKLF Encodes a Delayed Early Response Gene to Growth Stimulation-- To investigate the responsiveness of IKLF expression to growth stimulation, we conducted Northern blot analyses in cultured fibroblasts. NIH3T3 cells were first rendered quiescent by removing the serum from the medium and then stimulated by 15% FBS or the phorbol ester, PMA. As seen in Fig. 1, A and B, the level of IKLF transcripts was barely detectable in serum-starved, quiescent cells (time 0). Upon addition of FBS (Fig. 1A) or PMA (Fig. 1B), the levels of IKLF transcripts increased acutely and transiently, reaching a maximum after 2-3 h of treatment before returning to baseline levels. The enhancing effect of both stimuli was prevented in cells pretreated with the protein synthesis inhibitor, cycloheximide (Fig. 1C, CHX). These results indicate that IKLF is an early response gene to growth stimulation although this responsiveness requires protein synthesis. IKLF would therefore fall into the category of delayed early response genes (18, 19).

View larger version (50K): [in this window] [in a new window]   Fig. 1.   Activation of IKLF expression in NIH3T3 cells upon mitogenic stimulation. Before addition of mitogens, cells were incubated in medium stripped of serum for 24 h. Medium containing fresh FBS (15% v/v, A) or PMA (100 ng/ml, B) were then added to the cells for the various times indicated. RNA was extracted from the cells and probed simultaneously for the IKLF and GAPDH transcript content. In C, serum-deprived cells were preincubated in the absence (lanes 1, 3, and 5) or presence (lanes 2, 4, and 6) of 10 µg/ml CHX for 1 h, followed by an additional 1 h of medium alone (lanes 1 and 2), medium containing FBS (lanes 3 and 4), or PMA (lanes 5 and 6) in the absence or presence of CHX. RNA was extracted and probed for both IKLF and GAPDH.

Forced Expression of IKLF Causes Formation of Foci-- As a means to measure the effect of IKLF on cell proliferation, we conducted the focus formation assay previously developed for testing the transforming activity of oncogenes such as ras (17, 20). NIH3T3 fibroblasts were transfected with the various effector constructs and foci scored 2-3 weeks after transfection. As shown in Fig. 2, an expression plasmid containing the HA-tagged IKLF produced ~30% of the number of foci caused by activated Ha-Ras. A second construct containing IKLF without the HA-tag gave rise to similar results (not shown). In contrast, an expression plasmid containing GKLF failed to produce any foci, as were mock-transfected cells (Fig. 2). These results suggest that forced expression of IKLF causes focus formation in a manner similar to activated Ha-Ras, an activity that was not paralleled by GKLF.

View larger version (10K): [in this window] [in a new window]   Fig. 2.   Focus formation assay. Focus formation assay was conducted as described under "Experimental Procedures." NIH3T3 cells were transfected with 5 µg/10-cm dish of an expression plasmid containing Ha-Ras (16), IKLF·HA (12), or GKLF (10). The control was mock-transfected NIH3T3 cells. Foci were visualized by staining with methylene blue 2-3 weeks following transfection. Shown are the means of four independent experiments, each conducted in quadruplicate. Bars indicate S.E. *, p < 0.01 when compared with control, mock-transfected cells.

Constitutive Expression of IKLF Causes Accelerated Cell Growth-- To further investigate the effect of IKLF on cell proliferation, we established several clonally derived NIH3T3 cell lines that had been transfected with pBK-CMV-IKLF·HA or the pBK-CMV empty vector and selected with the antibiotic, G418. Two independent clones from each construct were chosen and examined. Fig. 3A shows that the two pBK-CMV-IKLF·HA- but not the two pBK-CMV-transfected clones (lanes 1 and 2 versus lanes 3 and 4, respectively) produced a full-length HA-tagged IKLF as detected by Western blot using a monoclonal antibody against the HA epitope. When the growth characteristics of these cells were examined and compared over a course of 5 days following seeding at a low density, it became apparent that the IKLF·HA-expressing cells proliferated at a much faster rate compared with the control, empty vector-transfected cells (Fig. 3B). Moreover, whereas the control cells ceased to proliferate after reaching confluency, the IKLF·HA-transfected cells continued to grow to several layers (Fig. 3C). These findings suggest that the growth of IKLF·HA-transfected cells was no longer subject to contact inhibition, providing further evidence for a proproliferative effect of IKLF.

View larger version (36K): [in this window] [in a new window]   Fig. 3.   Growth characteristics of cells stably transfected with IKLF. Clonal derivatives of NIH3T3 cells stably transfected with pBK-CMV-IKLF·HA or pBK-CMV were selected with G418 and analyzed for the content of IKLF·HA by Western blot analysis using an anti-HA monoclonal antibody (A). Shown are the results from two experiments each of IKLF·HA- and empty vector-transfected clones (I3 and I10 versus V3 and V5, respectively). In B, cells from each clone were seeded at a density of 2 × 105 cells/well in 6-well plates and fed every other day with DMEM containing 10% FBS. Three wells of cells from each clone were counted daily in triplicate, after seeding for up to 5 days. Shown are the mean cell numbers/well in log scale of IKLF·HA- and empty vector-transfected cells (I3 and I10 versus V3 and V5, respectively). Bars indicate S.E. C, typical morphology of IKLF·HA- and empty vector-transfected cells (left versus right, respectively) at 5 days after seeding. As shown, while the vector-transfected cells remained a monolayer, the IKLF·HA-transfected cells grew to multiple layers.

IKLF Causes Serum- and Anchorage-independent Growth-- The stably transfected NIH3T3 cells were subjected to additional and more stringent tests of cellular proliferation and transformation. In one, cells were seeded and maintained in medium containing only 1% FBS. Under these conditions, empty vector-transfected cells failed to proliferate. In fact, many perished because of the low-serum content. In contrast, IKLF·HA-transfected cells continued to proliferate at a relatively brisk rate albeit slightly slower than that when maintained in 10% FBS (compare Figs. 4A and 3B). A second test involved growth in soft agar (17). As seen in Fig. 4B, IKLF·HA-transfected cells formed colonies in an agar suspension as were Ha-ras-transfected cells at a ~1:3 ratio. In contrast, empty vector-transfected cells remained as single cells in the agar suspension without ever forming any colonies (Fig. 4C). The morphology and size of the colonies produced by IKLF·HA- and Ha-ras-transfected cells were very similar to each other (Fig. 4C).

View larger version (29K): [in this window] [in a new window]   Fig. 4.   Serum and anchorage dependence assays of IKLF-transfected cells. A, cells from the two IKLF·HA-transfected clones (I3 and I10) were seeded at a density of 2 × 105 cells/well in 6-well plates and maintained in 1% FBS for up to 6 days after seeding. Cells were counted every other day as described in the legend to Fig. 3 and plotted over time. The two empty vector-transfected clones (V3 and V5) failed to grow (not shown). B, Ha-ras-, IKLF·HA-, and empty vector-transfected cells were seeded in agar suspension, which were fed DMEM with 10% FBS every other day for 3 weeks. Colonies of cells were scored by visual inspection using an inverted phase-contrast microscope. Shown are the mean colony numbers in 8 random fields under a × 100 magnification. Bars indicate S.E. *, p < 0.005 compared with empty vector-transfected cells (V3 and V5). C, photomicrograph of a typical colony of Ha-ras- and IKLF·HA-transfected cells (left versus middle, respectively). Empty vector-transfected cells (right) produced no such colonies.

	COMPLEMENTARY DISCUSSION

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS COMPLEMENTARY DISCUSSION REFERENCES

Complementary DNA clones encoding mouse IKLF were initially identified because of sequence homology to LKLF (12). A human homolog was subsequently isolated based on its binding to a specific cis-sequence in the promoter of the lactoferrin gene promoter (21). In situ hybridization studies of both adult (12) and fetal intestinal tissues (13) showed that expression of IKLF is concentrated in the base of intestinal crypts. The in vivo pattern of IKLF expression in the intestinal tract therefore correlates with a proliferative phenotype, although a direct effect of IKLF on cellular proliferation was not established by these studies. It should be noted that IKLF is identical to the previously isolated BTEB2 (22), which, because of a sequencing error, has a shorter open-reading frame than IKLF (13). In a rabbit model, expression of BTEB2/IKLF is induced in activated smooth muscle cells (SMCs) in the neointima of balloon-injured aorta (23). Similarly, increased BTEB2 expression has been noted in proliferating SMCs at anastomotic vascular stricture (24) and this increased expression is a positive predictive factor for vascular restenosis in pathological conditions (25). Taken together, these studies suggest that activation of BTEB2/IKLF expression is correlated with a proliferative state.

The results of the current study indicate that expression of IKLF in cultured, quiescent NIH3T3 cells is acutely and transiently induced upon mitogenic stimulation by factors such as serum and phorbol ester. This induction is dependent on new protein synthesis as it is abolished in the presence of cycloheximide. A similar inductive response of BTEB2/IKLF was noted in cultured rabbit aorta-derived SMCs treated with PMA or basic fibroblast growth factor (26). The latter study also showed that expression of the immediate early response gene, Egr-1, is highly up-regulated by PMA and that Egr-1 binds to and activates the promoter of the BTEB2/IKLF gene (26). It is therefore possible that Egr-1 is an immediate mediator of induction of IKLF during proliferative responses.

Despite evidence from in vitro and in vivo studies demonstrating a correlation between IKLF expression and proliferation, it is not clear whether IKLF directly regulates cellular proliferation. The results of the current study are the first to show that constitutive expression of IKLF increases proliferation. We also show that IKLF alone is sufficient to cause a transformed phenotype as assessed by focus formation (Fig. 2), loss of contact inhibition (Fig. 3C), and gain of serum- (Fig. 4A) and anchorage-independent growth (Fig. 4, B and C). These observations therefore suggest that IKLF is potentially a mediator of cellular proliferation in the various in vivo and in vitro systems described above. Whether IKLF directly participates in regulating the cell cycle or whether expression of IKLF is increased in pathological conditions such as neoplasm remains to be investigated.

Based on the opposing patterns of expression of GKLF and IKLF in the intestine, Lingrel and co-workers (12) proposed that their gene products may have opposing effects in regulating proliferation and differentiation of the intestinal epithelium. Indeed, the antiproliferative effect of GKLF depicted by previous studies (10, 14) and the proproliferative effect of IKLF demonstrated by this study support their hypothesis. Biochemical evidence also suggests that the two proteins may have opposing functions. For example, the promoter of the SMC differentiation marker gene, SM22, is repressed by GKLF but activated by IKLF (27). Preliminary studies from our laboratory also indicate that GKLF and IKLF regulate the GKLF promoter in an opposing manner.² In view of the highly conserved sequence in the zinc finger region of the two proteins and the similar DNA sequences to which they bind (10, 11, 12, 14, 21), it would not be surprising that the two KLFs may coordinately regulate the expression of a group of genes through similar if not identical cis-elements. Further studies will demonstrate the biochemical mechanisms by which GKLF and IKLF antagonize each other in the context of regulating complex biological processes such as cellular proliferation and differentiation.

	ACKNOWLEDGEMENTS

We thank M. Conkright and Dr. J. Lingrel for providing pBK-CMV-IKLF·HA and pBK-CMV-IKLF (12) and Dr. R. Urrutia for providing the activated Ha-Ras (16) expression construct.

	FOOTNOTES

^* This work was supported in part by Grants DK52230 and CA84197 from the National Institutes of Health and the John G. Rangos Charitable Foundation.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked "advertisement" in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.

^¶ To whom correspondence should be addressed: Dept. of Medicine, Ross 918, The Johns Hopkins University School of Medicine, 720 Rutland Ave., Baltimore, MD 21205. Tel.: 410-955-9691; Fax: 410-955-9677; E-mail: vyang@jhmi.edu.

Published, JBC Papers in Press, January 10, 2000, DOI 10.1074/jbc.C000870200

² C. Mahatan and V. W. Yang, unpublished observations.

	ABBREVIATIONS

The abbreviations used are: KLF, Krüppel-like factor; GKLF, gut-enriched KLF; BTEB2, basic transcription element binding protein 2; CHX, cycloheximide; DMEM, Dulbecco's modified Eagle's medium; Egr-1, early growth response gene-1; FBS, fetal bovine serum; GAPDH, glyceraldehyde-3-phosphate dehydrogenase; HA, hemagglutinin; IKLF, intestinal-enriched Krüppel-like factor; PMA, phorbol 12-myristate 13-acetate; SMC, smooth muscle cell.

	REFERENCES

TOP ABSTRACT INTRODUCTION EXPERIMENTAL PROCEDURES RESULTS COMPLEMENTARY DISCUSSION REFERENCES

CiteULike

Complore

Connotea

Del.icio.us

Digg

Reddit

Technorati

This article has been cited by other articles:

				C. Wang, M. Han, X.-M. Zhao, and J.-K. Wen Kruppel-like Factor 4 is Required for the Expression of Vascular Smooth Muscle Cell Differentiation Marker Genes Induced by All-Trans Retinoic Acid J. Biochem., September 1, 2008; 144(3): 313 - 321. [Abstract] [Full Text] [PDF]

				H. Wan, F. Luo, S. E. Wert, L. Zhang, Y. Xu, M. Ikegami, Y. Maeda, S. M. Bell, and J. A. Whitsett Kruppel-like factor 5 is required for perinatal lung morphogenesis and function Development, August 1, 2008; 135(15): 2563 - 2572. [Abstract] [Full Text] [PDF]

				B. G. Goldstein, H.-H. Chao, Y. Yang, Y. A. Yermolina, J. W. Tobias, and J. P. Katz Overexpression of Kruppel-like factor 5 in esophageal epithelia in vivo leads to increased proliferation in basal but not suprabasal cells Am J Physiol Gastrointest Liver Physiol, June 1, 2007; 292(6): G1784 - G1792. [Abstract] [Full Text] [PDF]

				H. Zhang, A. Bialkowska, R. Rusovici, S. Chanchevalap, H. Shim, J. P. Katz, V. W. Yang, and C. C. Yun Lysophosphatidic Acid Facilitates Proliferation of Colon Cancer Cells via Induction of Kruppel-like Factor 5 J. Biol. Chem., May 25, 2007; 282(21): 15541 - 15549. [Abstract] [Full Text] [PDF]

				J. X. Du, C. C. Yun, A. Bialkowska, and V. W. Yang Protein Inhibitor of Activated STAT1 Interacts with and Up-regulates Activities of the Pro-proliferative Transcription Factor Kruppel-like Factor 5 J. Biol. Chem., February 16, 2007; 282(7): 4782 - 4793. [Abstract] [Full Text] [PDF]

				Y. Yang, B. G. Goldstein, H. Nakagawa, and J. P. Katz Kruppel-like factor 5 activates MEK/ERK signaling via EGFR in primary squamous epithelial cells FASEB J, February 1, 2007; 21(2): 543 - 550. [Abstract] [Full Text] [PDF]

				T. Fumoto, T. Yamaguchi, F. Hirose, and T. Osumi Orphan Nuclear Receptor Nur77 Accelerates the Initial Phase of Adipocyte Differentiation in 3T3-L1 Cells by Promoting Mitotic Clonal Expansion J. Biochem., February 1, 2007; 141(2): 181 - 192. [Abstract] [Full Text] [PDF]

				I. Sur, B. Rozell, V. Jaks, A. Bergstrom, and R. Toftgard Epidermal and craniofacial defects in mice overexpressing Klf5 in the basal layer of the epidermis J. Cell Sci., September 1, 2006; 119(17): 3593 - 3601. [Abstract] [Full Text] [PDF]

				N. Zhu, L. Gu, H. W. Findley, C. Chen, J.-T. Dong, L. Yang, and M. Zhou KLF5 Interacts with p53 in Regulating Survivin Expression in Acute Lymphoblastic Leukemia J. Biol. Chem., May 26, 2006; 281(21): 14711 - 14718. [Abstract] [Full Text] [PDF]

				D. Tong, K. Czerwenka, G. Heinze, M. Ryffel, E. Schuster, A. Witt, S. Leodolter, and R. Zeillinger Expression of KLF5 is a Prognostic Factor for Disease-Free Survival and Overall Survival in Patients with Breast Cancer Clin. Cancer Res., April 15, 2006; 12(8): 2442 - 2448. [Abstract] [Full Text] [PDF]

				S. Chanchevalap, M. O. Nandan, B. B. McConnell, L. Charrier, D. Merlin, J. P. Katz, and V. W. Yang Kruppel-like factor 5 is an important mediator for lipopolysaccharide-induced proinflammatory response in intestinal epithelial cells Nucleic Acids Res., February 25, 2006; 34(4): 1216 - 1223. [Abstract] [Full Text] [PDF]

				T. Suzuki, K. Aizawa, T. Matsumura, and R. Nagai Vascular Implications of the Kruppel-Like Family of Transcription Factors Arterioscler. Thromb. Vasc. Biol., June 1, 2005; 25(6): 1135 - 1141. [Abstract] [Full Text] [PDF]

				N. W. Bateman, D. Tan, R. G. Pestell, J. D. Black, and A. R. Black Intestinal Tumor Progression Is Associated with Altered Function of KLF5 J. Biol. Chem., March 26, 2004; 279(13): 12093 - 12101. [Abstract] [Full Text] [PDF]

				S. Usui, N. Sugimoto, N. Takuwa, S. Sakagami, S. Takata, S. Kaneko, and Y. Takuwa Blood Lipid Mediator Sphingosine 1-Phosphate Potently Stimulates Platelet-derived Growth Factor-A and -B Chain Expression through S1P1-Gi-Ras-MAPK-dependent Induction of Kruppel-like Factor 5 J. Biol. Chem., March 26, 2004; 279(13): 12300 - 12311. [Abstract] [Full Text] [PDF]

				K. Aizawa, T. Suzuki, N. Kada, A. Ishihara, K. Kawai-Kowase, T. Matsumura, K. Sasaki, Y. Munemasa, I. Manabe, M. Kurabayashi, et al. Regulation of Platelet-derived Growth Factor-A Chain by Kruppel-like Factor 5: NEW PATHWAY OF COOPERATIVE ACTIVATION WITH NUCLEAR FACTOR-{kappa}B J. Biol. Chem., January 2, 2004; 279(1): 70 - 76. [Abstract] [Full Text] [PDF]

				T. Nakamura, F. Unda, S. de-Vega, A. Vilaxa, S. Fukumoto, K. M. Yamada, and Y. Yamada The Kruppel-like Factor Epiprofin Is Expressed by Epithelium of Developing Teeth, Hair Follicles, and Limb Buds and Promotes Cell Proliferation J. Biol. Chem., January 2, 2004; 279(1): 626 - 634. [Abstract] [Full Text] [PDF]

				S. Miyamoto, T. Suzuki, S. Muto, K. Aizawa, A. Kimura, Y. Mizuno, T. Nagino, Y. Imai, N. Adachi, M. Horikoshi, et al. Positive and Negative Regulation of the Cardiovascular Transcription Factor KLF5 by p300 and the Oncogenic Regulator SET through Interaction and Acetylation on the DNA-Binding Domain Mol. Cell. Biol., December 1, 2003; 23(23): 8528 - 8541. [Abstract] [Full Text] [PDF]

				Z. Zhang and C. T. Teng Phosphorylation of Kruppel-like factor 5 (KLF5/IKLF) at the CBP interaction region enhances its transactivation function Nucleic Acids Res., April 15, 2003; 31(8): 2196 - 2208. [Abstract] [Full Text] [PDF]

				F. Chiambaretta, L. Blanchon, B. Rabier, W. W.-Y. Kao, J. J. Liu, B. Dastugue, D. Rigal, and V. Sapin Regulation of Corneal Keratin-12 Gene Expression by the Human Kruppel-like Transcription Factor 6 Invest. Ophthalmol. Vis. Sci., November 1, 2002; 43(11): 3422 - 3429. [Abstract] [Full Text] [PDF]

				D. T. Dang, W. Zhao, C. S. Mahatan, D. E. Geiman, and V. W. Yang Opposing effects of Kruppel-like factor 4 (gut-enriched Kruppel-like factor) and Kruppel-like factor 5 (intestinal-enriched Kruppel-like factor) on the promoter of the Kruppel-like factor 4 gene Nucleic Acids Res., July 1, 2002; 30(13): 2736 - 2741. [Abstract] [Full Text] [PDF]

				J.-S. Zhang, M. C. Moncrieffe, J. Kaczynski, V. Ellenrieder, F. G. Prendergast, and R. Urrutia A Conserved {alpha}-Helical Motif Mediates the Interaction of Sp1-Like Transcriptional Repressors with the Corepressor mSin3A Mol. Cell. Biol., August 1, 2001; 21(15): 5041 - 5049. [Abstract] [Full Text] [PDF]

				J. J. Bieker Kruppel-like Factors: Three Fingers in Many Pies J. Biol. Chem., September 7, 2001; 276(37): 34355 - 34358. [Full Text] [PDF]

This Article Abstract Full Text (PDF) All Versions of this Article: 276/10/6897    most recent C000870200v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Sun, R. Articles by Yang, V. W. Search for Related Content PubMed PubMed Citation Articles by Sun, R. Articles by Yang, V. W. Social Bookmarking