Palm Mutants in DNA Polymerases α and η Alter DNA Replication Fidelity and Translesion Activity

Atsuko Niimi, Siripan Limsirichaikul, Shonen Yoshida, Shigenori Iwai, Chikahide Masutani, Fumio Hanaoka, Eric T. Kool, Yukihiro Nishiyama, Motoshi Suzuki

Research output: Contribution to journalArticlepeer-review

74 Citations (Scopus)


We isolated active mutants in Saccharomyces cerevisiae DNA polymerase α that were associated with a defect in error discrimination. Among them, L868F DNA polymerase α has a spontaneous error frequency of 3 in 100 nucleotides and 570-fold lower replication fidelity than wild-type (WT) polymerase α. In vivo, mutant DNA polymerases confer a mutator phenotype and are synergistic with msh2 or msh6, suggesting that DNA polymerase α-dependent replication errors are recognized and repaired by mismatch repair. In vitro, L868F DNA polymerase α catalyzes efficient bypass of a cis-syn cyclobutane pyrimidine dimer, extending the 3′ T 26,000-fold more efficiently than the WT. Phe34 is equivalent to residue Leu868 in translesion DNA polymerase η, and the F34L mutant of S. cerevisiae DNA polymerase η has reduced translesion DNA synthesis activity in vitro. These data suggest that high-fidelity DNA synthesis by DNA polymerase α is required for genomic stability in yeast. The data also suggest that the phenylalanine and leucine residues in translesion and replicative DNA polymerases, respectively, might have played a role in the functional evolution of these enzyme classes.

Original languageEnglish
Pages (from-to)2734-2746
Number of pages13
JournalMolecular and Cellular Biology
Issue number7
Publication statusPublished - 04-2004
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Molecular Biology
  • Cell Biology


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