Novel cofactors and TFIIA mediate functional core promoter selectivity by the human TAFII150-containing TFIID complex

Mol Cell Biol. 1998 Nov;18(11):6571-83. doi: 10.1128/MCB.18.11.6571.

Abstract

TATA-binding protein-associated factors (TAFIIs) within TFIID control differential gene transcription through interactions with both activators and core promoter elements. In particular, TAFII150 contributes to initiator-dependent transcription through an unknown mechanism. Here, we address whether TAFIIs within TFIID are sufficient, in conjunction with highly purified general transcription factors (GTFs), for differential core promoter-dependent transcription by RNA polymerase II and whether additional cofactors are required. We identify the human homologue of Drosophila TAFII150 through cognate cDNA cloning and show that it is a tightly associated component of human TFIID. More importantly, we demonstrate that the human TAFII150-containing TFIID complex is not sufficient, in the context of all purified GTFs and RNA polymerase II, to mediate transcription synergism between TATA and initiator elements and initiator-directed transcription from a TAFII-dependent TATA-less promoter. Therefore, TAFII-promoter interactions are not sufficient for the productive core promoter-selective functions of TFIID. Consistent with this finding, we have partially purified novel cofactor activities (TICs) that potentiate the TAFII-mediated synergism between TATA and initiator elements (TIC-1) and TAFII-dependent transcription from TATA-less promoters (TIC-2 and -3). Furthermore, we demonstrate an essential function for TFIIA in TIC- and TAFII-dependent basal transcription from a TATA-less promoter. Our results reveal a parallel between the basal transcription activity of TAFIIs through core promoter elements and TAFII-dependent activator function.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • ARNTL Transcription Factors
  • Amino Acid Sequence
  • Basic Helix-Loop-Helix Transcription Factors
  • Cloning, Molecular
  • DNA-Binding Proteins / chemistry*
  • DNA-Binding Proteins / metabolism*
  • Drosophila Proteins*
  • Gene Expression Regulation / genetics
  • HeLa Cells
  • Humans
  • Molecular Sequence Data
  • Promoter Regions, Genetic / genetics*
  • RNA Polymerase II / metabolism
  • Recombinant Proteins / chemistry
  • Sequence Analysis, DNA
  • TATA-Binding Protein Associated Factors*
  • Trans-Activators / metabolism*
  • Transcription Factor TFIIA
  • Transcription Factor TFIID*
  • Transcription Factors / chemistry*
  • Transcription Factors / metabolism*
  • Transcription Factors / physiology*
  • Transcription, Genetic / genetics
  • Transcriptional Activation / physiology

Substances

  • ARNTL Transcription Factors
  • BMAL1 protein, human
  • Basic Helix-Loop-Helix Transcription Factors
  • DNA-Binding Proteins
  • Drosophila Proteins
  • Recombinant Proteins
  • TAF2 protein, human
  • TATA-Binding Protein Associated Factors
  • Trans-Activators
  • Transcription Factor TFIIA
  • Transcription Factor TFIID
  • Transcription Factors
  • e(y)1 protein, Drosophila
  • RNA Polymerase II

Associated data

  • GENBANK/AF040701