Transcription factor TFIIF is not required for initiation by RNA polymerase II, but it is essential to stabilize transcription factor TFIIB in early elongation complexes

Proc Natl Acad Sci U S A. 2011 Sep 20;108(38):15786-91. doi: 10.1073/pnas.1104591108. Epub 2011 Sep 6.

Abstract

Transcription factors TFIIB and TFIIF are both required for RNA polymerase II preinitiation complex (PIC) assembly, but their roles at and downstream of initiation are not clear. We now show that TFIIF phosphorylated by casein kinase 2 remains competent to support PIC assembly but is not stably retained in the PIC. PICs completely lacking TFIIF are not defective in initiation or subsequent promoter clearance, demonstrating that TFIIF is not required for initiation or clearance. Lack of TFIIF in the PIC reduces transcription levels at some promoters, coincident with reduced retention of TFIIB. TFIIB is normally associated with the early elongation complex and is only destabilized at +12 to +13. However, if TFIIF is not retained in the PIC, TFIIB can be lost immediately after initiation. TFIIF therefore has an important role in stabilizing TFIIB within the PIC and after transcription initiates.

Publication types

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

MeSH terms

  • Base Sequence
  • Casein Kinase II / genetics
  • Casein Kinase II / metabolism*
  • HeLa Cells
  • Humans
  • Immunoblotting
  • Phosphorylation
  • Promoter Regions, Genetic / genetics
  • RNA Polymerase II / metabolism*
  • Templates, Genetic
  • Transcription Factor TFIIB / genetics
  • Transcription Factor TFIIB / metabolism*
  • Transcription Factors, TFII / genetics
  • Transcription Factors, TFII / metabolism*
  • Transcription Initiation Site
  • Transcription, Genetic

Substances

  • Transcription Factor TFIIB
  • Transcription Factors, TFII
  • Casein Kinase II
  • RNA Polymerase II
  • transcription factor TFIIF