Smad-dependent stimulation of type I collagen gene expression in human skin fibroblasts by TGF-β involves functional cooperation with p300/CBP transcriptional coactivators

Asish K. Ghosh, Weihua Yuan, Yasuji Mori, John Varga*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

178 Scopus citations

Abstract

Transforming growth factor-β (TGF-β) stimulation of Type 1 collagen gene (COL1A2) transcription involves the Smad signal transduction pathway, but the mechanisms of Smad-mediated transcriptional activation are not fully understood. We now demonstrate that the ubiquitous transcriptional coactivators p300 and CREB-binding protein (CBP) enhanced basal as well as TGF-β- or Smad3-induced COL1A2 promoter activity, and stimulated the expression of endogenous Type I collagen. The adenoviral E1A oncoprotein abrogated stimulation of COL1A2 activity in transfected fibroblasts, and reduced the basal level of collagen gene expression. This effect was due to specific interaction of E1A with cellular p300/CBP because (a) a mutant form of E1A defective in p300 binding failed to abrogate stimulation, and (b) forced expression of p300/CBP restored the ability of TGF-β to stimulate COL1A2 promoter activity in the presence of E1A. The effect of p300 on COL1A2 transcription appeared to be due, in part, to its intrinsic acetyltransferase activity, as stimulation induced by a histone acetyltransferase-deficit nt mutant p300 was substantially reduced. Transactivation of COL1A2 by p300 involved the Smad signaling pathway, as Smad4-deficient cells failed to respond to p300, and stimulation was rescued by overexpression of Smad4. Furthermore, minimal constructs containing only the Smad-binding CAGACA element of COL1A2 were transactivated by p300 in the presence of TGF-β. These results indicate, for the first time, that the multifunctional p300/CBP coactivators play a major role in Smad-dependent TGF-β stimulation of collagen gene expression in fibroblasts.

Original languageEnglish (US)
Pages (from-to)3546-3555
Number of pages10
JournalOncogene
Volume19
Issue number31
DOIs
StatePublished - Jul 20 2000

Keywords

  • Coactivators
  • Signal transduction
  • Smads
  • Transforming growth factor-β
  • Type I collagen
  • p300/CBP

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

Fingerprint Dive into the research topics of 'Smad-dependent stimulation of type I collagen gene expression in human skin fibroblasts by TGF-β involves functional cooperation with p300/CBP transcriptional coactivators'. Together they form a unique fingerprint.

Cite this