Fidelity and damage bypass ability of Schizosaccharomyces pombe Eso1 protein, comprised of DNA polymerase eta and sister chromatid cohesion protein Ctf7

J Biol Chem. 2001 Nov 16;276(46):42857-62. doi: 10.1074/jbc.M106917200. Epub 2001 Sep 10.


DNA polymerase eta (Poleta) functions in error-free bypass of ultraviolet light-induced DNA lesions, and mutational inactivation of Poleta in humans causes the cancer prone syndrome, the variant form of xeroderma pigmentosum (XPV). Both Saccharomyces cerevisiae and human Poleta efficiently insert two adenines opposite the two thymines of a cyclobutane pyrimidine dimer. Interestingly, in the fission yeast Schizosaccharomyces pombe, the eso1(+) encoded protein is comprised of two domains, wherein the NH(2) terminus is highly homologous to Poleta, and the COOH terminus is highly homologous to the S. cerevisiae Ctf7 protein which is essential for the establishment of sister chromatid cohesion during S phase. Here we characterize the DNA polymerase activity of S. pombe GST-Eso1 fusion protein and a truncated version containing only the Poleta domain. Both proteins exhibit a similar DNA polymerase activity with a low processivity, and steady-state kinetic analyses show that on undamaged DNA, both proteins misincorporate nucleotides with frequencies of approximately 10(-2) to 10(-3). We also examine the two proteins for their ability to replicate a cyclobutane pyrimidine dimer-containing DNA template and find that both proteins replicate through the lesion equally well. Thus, fusion with Ctf7 has no significant effect on the DNA replication or damage bypass properties of Poleta. The possible role of Ctf7 fusion with Poleta in the replication of Cohesin-bound DNA sequences is discussed.

MeSH terms

  • Acetyltransferases*
  • Cell Cycle Proteins / chemistry*
  • Cell Cycle Proteins / metabolism*
  • DNA / biosynthesis
  • DNA / metabolism
  • DNA-Directed DNA Polymerase / chemistry*
  • DNA-Directed DNA Polymerase / metabolism*
  • Dimerization
  • Dose-Response Relationship, Drug
  • Fungal Proteins / chemistry*
  • Fungal Proteins / metabolism*
  • Glutathione Transferase / metabolism
  • Kinetics
  • Models, Chemical
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / metabolism*
  • Protein Binding
  • Protein Structure, Tertiary
  • S Phase
  • Saccharomyces cerevisiae Proteins*
  • Schizosaccharomyces / chemistry*
  • Schizosaccharomyces pombe Proteins*
  • Time Factors


  • Cell Cycle Proteins
  • Eso1 protein, S pombe
  • Fungal Proteins
  • Nuclear Proteins
  • Saccharomyces cerevisiae Proteins
  • Schizosaccharomyces pombe Proteins
  • DNA
  • Acetyltransferases
  • ECO1 protein, S cerevisiae
  • Glutathione Transferase
  • DNA-Directed DNA Polymerase
  • Rad30 protein