Requirement of RAD5 and MMS2 for postreplication repair of UV-damaged DNA in Saccharomyces cerevisiae

Mol Cell Biol. 2002 Apr;22(7):2419-26. doi: 10.1128/MCB.22.7.2419-2426.2002.

Abstract

UV lesions in the template strand block the DNA replication machinery. Genetic studies of the yeast Saccharomyces cerevisiae have indicated the requirement of the Rad6-Rad18 complex, which contains ubiquitin-conjugating and DNA-binding activities, in the error-free and mutagenic modes of damage bypass. Here, we examine the contributions of the REV3, RAD30, RAD5, and MMS2 genes, all of which belong to the RAD6 epistasis group, to the postreplication repair of UV-damaged DNA. Discontinuities, which are formed in DNA strands synthesized from UV-damaged templates, are not repaired in the rad5Delta and mms2Delta mutants, thus indicating the requirement of the Rad5 protein and the Mms2-Ubc13 ubiquitin-conjugating enzyme complex in this repair process. Some discontinuities accumulate in the absence of RAD30-encoded DNA polymerase eta (Poleta) but not in the absence of REV3-encoded DNA Polzeta. We concluded that replication through UV lesions in yeast is mediated by at least three separate Rad6-Rad18-dependent pathways, which include mutagenic translesion synthesis by Polzeta, error-free translesion synthesis by Poleta, and postreplication repair of discontinuities by a Rad5-dependent pathway. We suggest that newly synthesized DNA possessing discontinuities is restored to full size by a "copy choice" type of DNA synthesis which requires Rad5, a DNA-dependent ATPase, and also PCNA and Poldelta. The possible roles of the Rad6-Rad18 and the Mms2-Ubc13 enzyme complexes in Rad5-dependent damage bypass are discussed.

Publication types

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

MeSH terms

  • Adenosine Triphosphatases*
  • Centrifugation, Density Gradient
  • DNA Damage / radiation effects*
  • DNA Helicases
  • DNA Repair / radiation effects*
  • DNA Replication / radiation effects
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism
  • Dose-Response Relationship, Radiation
  • Epistasis, Genetic
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • Gene Deletion
  • Molecular Weight
  • Saccharomyces cerevisiae / enzymology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae / metabolism*
  • Saccharomyces cerevisiae / radiation effects
  • Saccharomyces cerevisiae Proteins / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Templates, Genetic
  • Ubiquitin-Protein Ligases
  • Ultraviolet Rays*

Substances

  • Fungal Proteins
  • MMS2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Ubiquitin-Protein Ligases
  • DNA-Directed DNA Polymerase
  • REV3 protein, S cerevisiae
  • Rad30 protein
  • Adenosine Triphosphatases
  • RAD5 protein, S cerevisiae
  • DNA Helicases