Schizosacchromyces pombe Dpb2 Binds to Origin DNA Early in S Phase and Is Required for Chromosomal DNA Replication

AUTOR(ES)

Feng, Wenyi

FONTE

The American Society for Cell Biology

RESUMO

Genetic evidence suggests that DNA polymerase epsilon (Pol ε) has a noncatalytic essential role during the early stages of DNA replication initiation. Herein, we report the cloning and characterization of the second largest subunit of Pol ε in fission yeast, called Dpb2. We demonstrate that Dpb2 is essential for cell viability and that a temperature-sensitive mutant of dpb2 arrests with a 1C DNA content, suggesting that Dpb2 is required for initiation of DNA replication. Using a chromatin immunoprecipitation assay, we show that Dpb2, binds preferentially to origin DNA at the beginning of S phase. We also show that the C terminus of Pol ε associates with origin DNA at the same time as Dpb2. We conclude that Dpb2 is an essential protein required for an early step in DNA replication. We propose that the primary function of Dpb2 is to facilitate assembly of the replicative complex at the start of S phase. These conclusions are based on the novel cell cycle arrest phenotype of the dpb2 mutant, on the previously uncharacterized binding of Dpb2 to replication origins, and on the observation that the essential function of Pol ε is not dependent on its DNA synthesis activity.

Documentos Relacionados

• Sld2, Which Interacts with Dpb11 in Saccharomyces cerevisiae, Is Required for Chromosomal DNA Replication
• Schizosaccharomyces pombe cdc20+ encodes DNA polymerase ɛ and is required for chromosomal replication but not for the S phase checkpoint
• DPB2, the gene encoding DNA polymerase II subunit B, is required for chromosome replication in Saccharomyces cerevisiae.
• DRC1, DNA replication and checkpoint protein 1, functions with DPB11 to control DNA replication and the S-phase checkpoint in Saccharomyces cerevisiae
• Protein phosphatase 2A is required for the initiation of chromosomal DNA replication