Sld2, which interacts with Dpb11 in Saccharomyces cerevisiae, is required for chromosomal DNA replication

Mol Cell Biol. 1998 Oct;18(10):6102-9. doi: 10.1128/MCB.18.10.6102.

Abstract

The DPB11 gene, which genetically interacts with DNA polymerase II (epsilon), one of three replicative DNA polymerases, is required for DNA replication and the S phase checkpoint in Saccharomyces cerevisiae. To identify factors interacting with Dbp11, we have isolated sld (synthetically lethal with dpb11-1) mutations which fall into six complementation groups (sld1 to -6). In this study, we characterized SLD2, encoding an essential 52-kDa protein. High-copy SLD2 suppressed the thermosensitive growth defect caused by dpb11-1. Conversely, high-copy DPB11 suppressed the temperature-sensitive growth defect caused by sld2-6. The interaction between Sld2 and Dpb11 was detected in a two-hybrid assay. This interaction was evident at 25 degreesC but not at 34 degreesC when Sld2-6 or Dpb11-1 replaced its wild-type protein. No interaction between Sld2-6 and Dpb11-1 could be detected even at 25 degreesC. Immunoprecipitation experiments confirmed that Dpb11 physically interacts with Sld2. sld2-6 cells were defective in DNA replication at the restrictive temperature, as were dpb11-1 cells. Further, in dpb11-1 and sld2-6 cells, the bubble-shaped replication intermediates formed in the region of the autonomously replicating sequence reduced quickly after a temperature shift. These results strongly suggest the involvement of the Dpb11-Sld2 complex in a step close to the initiation of DNA replication.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Binding Sites
  • Carrier Proteins / genetics
  • Carrier Proteins / physiology*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism*
  • Cell Division
  • DNA Replication*
  • DNA, Fungal / biosynthesis
  • Fungal Proteins / genetics
  • Fungal Proteins / metabolism*
  • G1 Phase
  • Molecular Sequence Data
  • Mutation
  • S Phase
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins*

Substances

  • Carrier Proteins
  • Cell Cycle Proteins
  • DNA, Fungal
  • DPB11 protein, S cerevisiae
  • Fungal Proteins
  • SLD2 protein, S cerevisiae
  • Saccharomyces cerevisiae Proteins