Heat-shock Inactivation of the TFIIH-associated Kinase and Change in the Phosphorylation Sites on the C-terminal Domain of RNA Polymerase II

Nucleic Acids Res. 1997 Feb 15;25(4):694-700. doi: 10.1093/nar/25.4.694.

Abstract

The C-terminal domain (CTD) of the RNA polymerase II largest subunit (RPB1) plays a central role in transcription. The CTD is unphosphorylated when the polymerase assembles into a preinitiation complex of transcription and becomes heavily phosphorylated during promoter clearance and entry into elongation of transcription. A kinase associated to the general transcription factor TFIIH, in the preinitiation complex, phosphorylates the CTD. The TFIIH-associated CTD kinase activity was found to decrease in extracts from heat-shocked HeLa cells compared to unstressed cells. This loss of activity correlated with a decreased solubility of the TFIIH factor. The TFIIH-kinase impairment during heat-shock was accompanied by the disappearance of a particular phosphoepitope (CC-3) on the RPB1 subunit. The CC-3 epitope was localized on the C-terminal end of the CTD and generated in vitro when the RPB1 subunit was phosphorylated by the TFIIH-associated kinase but not by another CTD kinase such as MAP kinase. In apparent discrepancy, the overall RPB1 subunit phosphorylation increased during heat-shock. The decreased activity in vivo of the TFIIH kinase might be compensated by a stress-activated CTD kinase such as MAP kinase. These results also suggest that heat-shock gene transcription may have a weak requirement for TFIIH kinase activity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Binding Sites, Antibody
  • Enzyme Activation
  • HeLa Cells
  • Hot Temperature*
  • Humans
  • Molecular Sequence Data
  • Phosphorylation
  • Protein Kinases / immunology
  • Protein Kinases / metabolism*
  • RNA Polymerase II / chemistry*
  • RNA Polymerase II / metabolism*
  • Solubility
  • Transcription Factor TFIIH
  • Transcription Factors / metabolism*
  • Transcription Factors, TFII*

Substances

  • Transcription Factors
  • Transcription Factors, TFII
  • Transcription Factor TFIIH
  • Protein Kinases
  • carboxy-terminal domain kinase
  • RNA Polymerase II

Associated data

  • GENBANK/X63564