Role of DNA polymerase eta in the bypass of abasic sites in yeast cells

Nucleic Acids Res. 2004 Jul 29;32(13):3984-94. doi: 10.1093/nar/gkh710. Print 2004.


Abasic (AP) sites are major DNA lesions and are highly mutagenic. AP site-induced mutagenesis largely depends on translesion synthesis. We have examined the role of DNA polymerase eta (Poleta) in translesion synthesis of AP sites by replicating a plasmid containing a site-specific AP site in yeast cells. In wild-type cells, AP site bypass resulted in preferred C insertion (62%) over A insertion (21%), as well as -1 deletion (3%), and complex event (14%) containing multiple mutations. In cells lacking Poleta (rad30), Rev1, Polzeta (rev3), and both Poleta and Polzeta, translesion synthesis was reduced to 30%, 30%, 15% and 3% of the wild-type level, respectively. C insertion opposite the AP site was reduced in rad30 mutant cells and was abolished in cells lacking Rev1 or Polzeta, but significant A insertion was still detected in these mutant cells. While purified yeast Polalpha effectively inserted an A opposite the AP site in vitro, purified yeast Poldelta was much less effective in A insertion opposite the lesion due to its 3'-->5' proofreading exonuclease activity. Purified yeast Poleta performed extension synthesis from the primer 3' A opposite the lesion. These results show that Poleta is involved in translesion synthesis of AP sites in yeast cells, and suggest that an important role of Poleta is to catalyze extension following A insertion opposite the lesion. Consistent with these conclusions, rad30 mutant cells were sensitive to methyl methanesulfonate (MMS), and rev1 rad30 or rev3 rad30 double mutant cells were synergistically more sensitive to MMS than the respective single mutant strains.

Publication types

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

MeSH terms

  • Base Sequence
  • DNA Damage*
  • DNA Polymerase III
  • DNA, Fungal / biosynthesis
  • DNA, Fungal / chemistry
  • DNA-Directed DNA Polymerase / metabolism
  • DNA-Directed DNA Polymerase / physiology*
  • Exodeoxyribonucleases / metabolism
  • Fungal Proteins / metabolism
  • Genetic Vectors
  • Methyl Methanesulfonate / toxicity
  • Models, Genetic
  • Mutagens / toxicity
  • Nucleotidyltransferases
  • Plasmids / genetics
  • Saccharomyces cerevisiae / drug effects
  • Saccharomyces cerevisiae / enzymology*
  • Saccharomyces cerevisiae / genetics
  • Saccharomyces cerevisiae Proteins / metabolism
  • Templates, Genetic


  • DNA, Fungal
  • Fungal Proteins
  • Mutagens
  • POL3 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins
  • Methyl Methanesulfonate
  • Nucleotidyltransferases
  • REV1 protein, S cerevisiae
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • REV3 protein, S cerevisiae
  • Rad30 protein
  • Exodeoxyribonucleases