A human DNA polymerase eta complex containing Rad18, Rad6 and Rev1; proteomic analysis and targeting of the complex to the chromatin-bound fraction of cells undergoing replication fork arrest

Genes Cells. 2006 Jul;11(7):731-44. doi: 10.1111/j.1365-2443.2006.00974.x.


DNA polymerase eta (Poleta) is responsible for efficient translesion synthesis (TLS) past cis-syn cyclobutane thymine dimers (TT dimers), the major DNA lesions induced by UV irradiation. Loss of human Poleta leads to xeroderma pigmentosum variant syndrome, clearly indicating that Poleta plays a vital role in preventing skin cancer caused by exposure to sunlight. To further examine Poleta functions and the mechanisms that regulate this important protein, Poleta complexes were purified from HeLa cells over-expressing epitope-tagged Poleta, and polypeptides associated with Poleta, including Rad18, Rad6 and Rev1, were identified by a combination of mass spectrometry and Western blot analysis. The chromatin-bound fractions of cells subjected to UV irradiation, S phase synchronization, or S phase arrest were specifically enriched in such complexes. These results suggest that arrested replication forks strengthen interactions among Poleta, Rad18/Rad6 and Rev1, consistent with the requirement for effective TLS by Poleta at sites of DNA lesions.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chromatin / genetics
  • Chromatin / metabolism*
  • Chromatin / radiation effects
  • DNA Damage
  • DNA Replication / genetics
  • DNA Replication / physiology*
  • DNA Replication / radiation effects
  • DNA-Binding Proteins / metabolism*
  • DNA-Directed DNA Polymerase / isolation & purification
  • DNA-Directed DNA Polymerase / metabolism*
  • HeLa Cells
  • Humans
  • Mass Spectrometry / methods
  • Nuclear Proteins
  • Nucleotidyltransferases / metabolism*
  • Protein Transport
  • Proteomics / methods
  • Ubiquitin-Protein Ligases


  • Chromatin
  • DNA-Binding Proteins
  • Nuclear Proteins
  • RAD18 protein, human
  • Ubiquitin-Protein Ligases
  • Nucleotidyltransferases
  • REV1 protein, human
  • DNA-Directed DNA Polymerase
  • Rad30 protein