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DNA Polymerase II, the Epsilon Polymerase of Saccharomyces cerevisiae

1993; Academic Press; Linguagem: Inglês

10.1016/s0079-6603(08)61019-3

2211-9108

Alan Morrison, Akio Sugino,

CRISPR and Genetic Engineering

This chapter discusses the data on DNA polymerase II in the context of current knowledge of eukaryotic DNA polymerases, DNA replication and its fidelity, and DNA repair. DNA polymerase II has been proffered as the “repair polymerase.” Contrary to the implicit assumption, DNA repair is not a single process but an array of different pathways that have been dissected at least partially by genetic studies. It cannot be presumed that a particular polymerase acts in repair but not in replication, or that a single polymerase performs all DNA repair, or that each repair pathway has a dedicated polymerase. If DNA polymerase II is involved in the repair of damaged DNA, it might be possible in principle to obtain radiation-sensitive mutants either in POL2, or in DPB2, or DPB3. Further evidence implicating DNA polymerase II in DNA replication comes from the spontaneous mutator phenotype of the exonuclease-deficient pol2-4 mutant. While a spontaneous mutator phenotype may also arise in DNA repair mutants, the pol2-4 mutation does not confer sensitivity to DNA-damaging agents, and the epistatic relationships discussed in the chapter, link the DNA polymerase II 3’→5’ exonuclease with DNA replication.