Translesion synthesis across the (6-4) photoproduct and its Dewar valence isomer by the Y-family and engineered DNA polymerases

Nucleic Acids Symp Ser (Oxf). 2008:(52):339-40. doi: 10.1093/nass/nrn171.


We analyzed the translesion synthesis across the UV-induced lesions, the (6-4) photoproduct and its Dewar valence isomer, by using human DNA polymerases eta and iota in vitro. The primer extension experiments revealed that pol eta tended to incorporate dG opposite the 3' component of both lesions, but the incorporation efficiency for the Dewar isomer was higher than that for the (6-4) photoproduct. On the other hand, pol iota was likely to incorporate dA opposite the 3' components of the (6-4) photoproduct and its Dewar isomer with a similar efficiency. Elongation after the incorporation opposite the UV lesions was not observed for these Y-family polymerases. We further analyzed the bypass ability of an engineered polymerase developed from Thermus DNA polymerase for the amplification of ancient DNA. This polymerase could bypass the Dewar isomer more efficiently than the (6-4) photoproduct.

MeSH terms

  • DNA / biosynthesis
  • DNA / chemistry
  • DNA Polymerase iota
  • DNA-Directed DNA Polymerase / genetics
  • DNA-Directed DNA Polymerase / metabolism*
  • Humans
  • Isomerism
  • Mutation
  • Protein Engineering
  • Pyrimidine Dimers / chemistry*
  • Thermus / enzymology


  • Pyrimidine Dimers
  • pyrimidine-pyrimidone dimer
  • DNA
  • DNA-Directed DNA Polymerase
  • Rad30 protein
  • DNA Polymerase iota