title: The gut-enriched Kruppel-like factor (Kruppel-like factor 4) mediates the transactivating effect of p53 on the p21WAF1/Cip1 promoter.
abstract: An important mechanism by which the tumor suppressor p53 maintains genomic stability is to induce cell cycle arrest through activation of the cyclin-dependent kinase inhibitor p21(WAF1/Cip1) gene. We show that the gene encoding the gut-enriched Krüppel-like factor (GKLF, KLF4) is concurrently induced with p21(WAF1/Cip1) during serum deprivation and DNA damage elicited by methyl methanesulfonate. The increases in expression of both Gklf and p21(WAF1/Cip1) due to DNA damage are dependent on p53. Moreover, during the first 30 min of methyl methanesulfonate treatment, the rise in Gklf mRNA level precedes that in p21(WAF1/Cip1), suggesting that GKLF may be involved in the induction of p21(WAF1/Cip1). Indeed, GKLF activates p21(WAF1/Cip1) through a specific Sp1-like cis-element in the p21(WAF1/Cip1) proximal promoter. The same element is also required by p53 to activate the p21(WAF1/Cip1) promoter, although p53 does not bind to it. Potential mechanisms by which p53 activates the p21(WAF1/Cip1) promoter include a physical interaction between p53 and GKLF and the transcriptional induction of Gklf by p53. Consequently, the two transactivators cause a synergistic induction of the p21(WAF1/Cip1) promoter activity. The physiological relevance of GKLF in mediating p53-dependent induction of p21(WAF1/Cip1) is demonstrated by the ability of antisense Gklf oligonucleotides to block the production of p21(WAF1/Cip1) in response to p53 activation. These findings suggest that GKLF is an essential mediator of p53 in the transcriptional induction of p21(WAF1/Cip1) and may be part of a novel pathway by which cellular responses to stress are modulated.
authors.affiliation: Departments of Medicine and Biological Chemistry, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA.
authors.forename: W
authors.initials: W
authors.lastname: Zhang
authors.forename: D E
authors.initials: DE
authors.lastname: Geiman
authors.forename: J M
authors.initials: JM
authors.lastname: Shields
authors.forename: D T
authors.initials: DT
authors.lastname: Dang
authors.forename: C S
authors.initials: CS
authors.lastname: Mahatan
authors.forename: K H
authors.initials: KH
authors.lastname: Kaestner
authors.forename: J R
authors.initials: JR
authors.lastname: Biggs
authors.forename: A S
authors.initials: AS
authors.lastname: Kraft
authors.forename: V W
authors.initials: VW
authors.lastname: Yang
mesh_terms: D016475:3T3 Cells; D000818:Animals; D002460:Cell Line; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins / Q000235:genetics*; D004268:DNA-Binding Proteins; D006131:Growth Inhibitors / Q000378:metabolism*; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D008741:Methyl Methanesulfonate / Q000494:pharmacology; D051379:Mice; D016133:Polymerase Chain Reaction; D011401:Promoter Regions, Genetic; D011817:Rabbits; D016329:Sp1 Transcription Factor / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism*; D015533:Transcriptional Activation; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D016335:Zinc Fingers
chemical_list: C493957:Cdkn1a protein, mouse; D050759:Cyclin-Dependent Kinase Inhibitor p21; D016213:Cyclins; D004268:DNA-Binding Proteins; D006131:Growth Inhibitors; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D051741:Kruppel-Like Transcription Factors; D016329:Sp1 Transcription Factor; D014157:Transcription Factors; D016159:Tumor Suppressor Protein p53; D008741:Methyl Methanesulfonate