A transcription-independent role for TFIIB in gene looping

Mol Cell. 2007 Sep 7;27(5):806-16. doi: 10.1016/j.molcel.2007.07.013.

Abstract

Recent studies demonstrated the existence of gene loops that juxtapose the promoter and terminator regions of genes with exceptionally long ORFs in yeast. Here we report that looping is not idiosyncratic to long genes but occurs between the distal ends of genes with ORFs as short as 1 kb. Moreover, looping is dependent upon the general transcription factor TFIIB: the E62K (glutamic acid 62 --> lysine) form of TFIIB adversely affects looping at every gene tested, including BLM10, SAC3, GAL10, SEN1, and HEM3. TFIIB crosslinks to both the promoter and terminator regions of the PMA1 and BLM10 genes, and its association with the terminator, but not the promoter, is adversely affected by E62K and by depletion of the Ssu72 component of the CPF 3' end processing complex, and is independent of TBP. We propose a model suggesting that TFIIB binds RNAP II at the terminator, which in turn associates with the promoter scaffold.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Chromatin Immunoprecipitation
  • Gene Expression Regulation, Fungal*
  • Models, Genetic*
  • Nucleic Acid Conformation
  • Open Reading Frames
  • Promoter Regions, Genetic
  • RNA Polymerase II / metabolism
  • Saccharomyces cerevisiae Proteins / chemistry
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Saccharomyces cerevisiae Proteins / physiology*
  • Terminator Regions, Genetic
  • Transcription Factor TFIIB / chemistry
  • Transcription Factor TFIIB / genetics
  • Transcription Factor TFIIB / physiology*
  • Transcription, Genetic

Substances

  • SUA7 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Transcription Factor TFIIB
  • RNA Polymerase II