Efficiency, specificity and DNA polymerase-dependence of translesion replication across the oxidative DNA lesion 8-oxoguanine in human cells

Mutat Res. 2002 Dec 29;510(1-2):81-90. doi: 10.1016/s0027-5107(02)00254-3.


The oxidation product of guanine, 8-oxoguanine, is a major lesion formed in DNA by intracellular metabolism, ionizing radiation, and tobacco smoke. Using a recently developed method for the quantitative analysis of translesion replication, we have studied the bypass of 8-oxoguanine in vivo by transfecting human cells with a gapped plasmid carrying a site-specific 8-oxoguanine in the ssDNA region. The efficiency of bypass in the human large-cell lung carcinoma cell line H1299 was 80%, and it was similar when assayed in the presence of aphidicolin, an inhibitor of DNA polymerases alpha, delta and epsilon. A similar extent of bypass was observed also in XP-V cells, defective in pol eta, both in the absence and presence of aphidicolin. DNA sequence analysis indicated that the major nucleotide inserted opposite the 8-oxoguanine was the correct nucleotide C, both in H1299 cells (81%) and in XP-V cells (77%). The major mutagenic event was the insertion of an A, both in H1299 and XP-V cells, and it occurred at a frequency of 16-17%, significantly higher than previously reported. Interestingly, the misinsertion frequency of A opposite 8-oxoguanine was decreased in XP-V cells in the presence of aphidicolin, and misinsertion of G was observed. This modulation of the mutagenic specificity at 8-oxoguanine is consistent with the notion that while not essential for the bypass reaction, pol eta and pol delta, when present, are involved in bypass of 8-oxoguanine in vivo.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cells, Cultured
  • DNA Damage*
  • DNA Polymerase III / metabolism
  • DNA Repair
  • DNA Replication*
  • DNA-Directed DNA Polymerase / metabolism*
  • Escherichia coli / genetics
  • Escherichia coli / metabolism
  • Guanine / analogs & derivatives*
  • Guanine / chemistry*
  • Humans
  • Molecular Sequence Data
  • Mutation
  • Plasmids / chemistry
  • Plasmids / genetics
  • Transfection


  • 8-hydroxyguanine
  • Guanine
  • DNA Polymerase III
  • DNA-Directed DNA Polymerase
  • Rad30 protein