title: Sld2, which interacts with Dpb11 in Saccharomyces cerevisiae, is required for chromosomal DNA replication.
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.
authors.affiliation: Department of Biochemistry and Molecular Biology, Research Institute for Microbial Diseases, Osaka University, Suita, Osaka 565-0871 Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Kamimura
authors.forename: H
authors.initials: H
authors.lastname: Masumoto
authors.forename: A
authors.initials: A
authors.lastname: Sugino
authors.forename: H
authors.initials: H
authors.lastname: Araki
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D002352:Carrier Proteins / Q000235:genetics / Q000502:physiology*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism*; D002455:Cell Division; D004261:DNA Replication; D004271:DNA, Fungal / Q000096:biosynthesis; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D016193:G1 Phase; D008969:Molecular Sequence Data; D009154:Mutation; D016196:S Phase; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D002352:Carrier Proteins; D018797:Cell Cycle Proteins; D004271:DNA, Fungal; C097185:DPB11 protein, S cerevisiae; D005656:Fungal Proteins; C115043:SLD2 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins