A direct intersection between p53 and transforming growth factor β pathways targets chromatin modification and transcription repression of the α-fetoprotein gene

Deepti S. Wilkinson, Stacey K. Ogden, Sabrina A. Stratton, Julie L. Piechan, Thi T. Nguyen, George A. Smulian, Michelle Craig Barton

Research output: Contribution to journalArticlepeer-review

61 Scopus citations

Abstract

We purified the oncoprotein SnoN and found that it functions as a corepressor of the tumor suppressor p53 in the regulation of the hepatic α-fetoprotein (AFP) tumor marker gene. p53 promotes SnoN and histone deacetylase interaction at an overlapping Smad binding, p53 regulatory element (SBE/p53RE) in AFP. Comparison of wild-type and p53-null mouse liver tissue by using chromatin immunoprecipitation (ChIP) reveals that the absence of p53 protein correlates with the disappearance of SnoN at the SBE/p53RE and loss of AFP developmental repression. Treatment of AFP-expressing hepatoma cells with transforming growth factor-β1 (TGF-β1) induced SnoN transcription and Smad2 activation, concomitant with AFP repression. ChIP assays show that TGF-β1 stimulates p53, Smad4, P-Smad2 binding, and histone H3K9 deacetylation and methylation, at the SBE/p53RE. Depletion, by small interfering RNA, of SnoN and/or p53 in hepatoma cells disrupted repression of AFP transcription. These findings support a model of cooperativity between p53 and TGF-β effectors in chromatin modification and transcription repression of an oncodevelopmental tumor marker gene.

Original languageEnglish (US)
Pages (from-to)1200-1212
Number of pages13
JournalMolecular and cellular biology
Volume25
Issue number3
DOIs
StatePublished - Feb 2005
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology

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