"Action-at-a-distance" mutagenesis. 8-oxo-7, 8-dihydro-2'-deoxyguanosine causes base substitution errors at neighboring template sites when copied by DNA polymerase beta

J Biol Chem. 1999 May 28;274(22):15920-6. doi: 10.1074/jbc.274.22.15920.


8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG), a common oxidative DNA lesion, favors a syn-conformation in DNA, enabling formation of stable 8-oxo-dG.A base mispairs resulting in G.C --> T.A transversion mutations. When human DNA polymerase (pol) beta was used to copy a short single-stranded gap containing a site-directed 8-oxo-dG lesion, incorporation of dAMP opposite 8-oxo-dG was slightly favored over dCMP depending on "downstream" sequence context. Unexpectedly, however, a significant increase in dCMP.A and dGMP.A mispairs was also observed at the "upstream" 3'-template site adjacent to the lesion. Errors at these undamaged template sites occurred in four sequence contexts with both gapped and primed single-stranded DNA templates, but not when pol alpha replaced pol beta. Error rates at sites adjacent to 8-oxo-dG were roughly 1% of the values opposite 8-oxo-dG, potentially generating tandem mutations during in vivo short-gap repair synthesis by pol beta. When 8-oxo-dG was replaced with 8-bromo-2'-deoxyguanosine, incorporation of dCMP was strongly favored by both enzymes, with no detectable misincorporation occurring at neighboring template sites.

Publication types

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

MeSH terms

  • 8-Hydroxy-2'-Deoxyguanosine
  • Base Pairing / genetics
  • DNA / chemistry
  • DNA Damage / genetics
  • DNA Polymerase I / metabolism
  • DNA Polymerase beta / metabolism*
  • Deoxyguanosine / analogs & derivatives*
  • Deoxyguanosine / pharmacology
  • Guanosine / analogs & derivatives
  • Humans
  • Kinetics
  • Mutagenesis / genetics*
  • Mutation / genetics
  • Nucleic Acid Conformation
  • Nucleotides / metabolism
  • Templates, Genetic


  • Nucleotides
  • Guanosine
  • 8-Hydroxy-2'-Deoxyguanosine
  • DNA
  • DNA Polymerase I
  • DNA Polymerase beta
  • Deoxyguanosine