Inhibition of MMTV transcription by HDAC inhibitors occurs independent of changes in chromatin remodeling and increased histone acetylation

Niveen M. Mulholland, Edlyn Soeth, Catharine L. Smith

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

Increased histone acetylation has been associated with activated gene transcription and decreased acetylation with repression. However, there is a growing number of genes known, which are downregulated by histone deacetylase (HDAC) inhibitors through unknown mechanisms. This study examines the mechanism by which the mouse mammary tumor virus (MMTV) promoter is repressed by the HDAC inhibitor, trichostatin A (TSA). We find that this repression is transcriptional in nature and that it occurs in the presence and absence of glucocorticoids. TSA decreases MMTV transcription at a rapid rate, reaching maximum in 30-60 min. In contrast with previous reports, the repression does not correlate with an inhibition of glucocorticoid-induced nuclease hypersensitivity or NF1-binding at the MMTV promoter. Surprisingly, TSA does not induce sizable increases in histone acetylation at the MMTV promoter nor does it inhibit histone deacetylation, which accompanies deactivation of the glucocorticoid-activated MMTV promoter. Repression of MMTV transcription by TSA does not depend on the chromatin organization of the promoter because a transiently transfected MMTV promoter construct with a disorganized nucleoprotein structure was also repressed by TSA treatment. Mutational analysis of the MMTV promoter indicates that repression by TSA is mediated through the TATA box region. These results suggest a novel mechanism that involves acetylation of nonhistone proteins necessary for basal transcription.

Original languageEnglish (US)
Pages (from-to)4807-4818
Number of pages12
JournalOncogene
Volume22
Issue number31
DOIs
StatePublished - Jul 31 2003
Externally publishedYes

Keywords

  • Chromatin
  • Histone deacetylase
  • Mouse mammary tumor virus
  • Transcription

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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