UV-induced ubiquitination of RNA polymerase II: a novel modification deficient in Cockayne syndrome cells

Proc Natl Acad Sci U S A. 1996 Oct 15;93(21):11586-90. doi: 10.1073/pnas.93.21.11586.

Abstract

Damage to actively transcribed DNA is preferentially repaired by the transcription-coupled repair (TCR) system. TCR requires RNA polymerase II (Pol II), but the mechanism by which repair enzymes preferentially recognize and repair DNA lesions on Pol II-transcribed genes is incompletely understood. Herein we demonstrate that a fraction of the large subunit of Pol II (Pol II LS) is ubiquitinated after exposing cells to UV-radiation or cisplatin but not several other DNA damaging agents. This novel covalent modification of Pol II LS occurs within 15 min of exposing cells to UV-radiation and persists for about 8-12 hr. Ubiquitinated Pol II LS is also phosphorylated on the C-terminal domain. UV-induced ubiquitination of Pol II LS is deficient in fibroblasts from individuals with two forms of Cockayne syndrome (CS-A and CS-B), a rare disorder in which TCR is disrupted. UV-induced ubiquitination of Pol II LS can be restored by introducing cDNA constructs encoding the CSA or CSB genes, respectively, into CS-A or CS-B fibroblasts. These results suggest that ubiquitination of Pol II LS plays a role in the recognition and/or repair of damage to actively transcribed genes. Alternatively, these findings may reflect a role played by the CSA and CSB gene products in transcription.

Publication types

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

MeSH terms

  • Cell Line
  • Cisplatin / pharmacology
  • Cockayne Syndrome / enzymology*
  • Cockayne Syndrome / genetics
  • DNA Damage
  • DNA Repair
  • HeLa Cells
  • Humans
  • Hydrogen Peroxide / pharmacology
  • Phosphorylation
  • RNA Polymerase II / genetics*
  • RNA Polymerase II / metabolism*
  • RNA Polymerase II / radiation effects
  • Recombinant Proteins / metabolism
  • Recombinant Proteins / radiation effects
  • Transcription, Genetic
  • Transfection
  • Ubiquitins / metabolism*
  • Ultraviolet Rays*

Substances

  • Recombinant Proteins
  • Ubiquitins
  • Hydrogen Peroxide
  • RNA Polymerase II
  • Cisplatin