Sld3, which interacts with Cdc45 (Sld4), functions for chromosomal DNA replication in Saccharomyces cerevisiae

EMBO J. 2001 Apr 17;20(8):2097-107. doi: 10.1093/emboj/20.8.2097.

Abstract

Cdc45, which binds to the minichromosomal maintenance (Mcm) proteins, has a pivotal role in the initiation and elongation steps of chromosomal DNA replication in eukaryotes. Here we show that throughout the cell cycle in Saccharomyces cerevisiae, Cdc45 forms a complex with a novel factor, Sld3. Consistently, Sld3 and Cdc45 associate simultaneously with replication origins in the chromatin immunoprecipitation assay: both proteins associate with early-firing origins in G(1) phase and with late-firing origins in late S phase. Moreover, the origin associations of Sld3 and Cdc45 are mutually dependent. The temperature-sensitive sld3 mutation confers a defect in DNA replication at the restrictive temperature and reduces an interaction not only between Sld3 and Cdc45, but also between Cdc45 and Mcm2. These results suggest that the Sld3-Cdc45 complex associates with replication origins through Mcm proteins. At the restrictive temperature in sld3-5 cells, replication factor A, a single-strand DNA binding protein, does not associate with origins. Therefore, the origin association of Sld3-Cdc45 complex is prerequisite for origin unwinding in the initiation of DNA replication.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Carrier Proteins / metabolism*
  • Cell Cycle Proteins / genetics*
  • Cell Cycle Proteins / metabolism*
  • Chromosomes, Fungal / metabolism*
  • DNA Replication*
  • DNA, Fungal / biosynthesis*
  • DNA-Binding Proteins / genetics*
  • DNA-Binding Proteins / metabolism*
  • Gene Dosage
  • Genes, Essential
  • Genes, Fungal
  • Nuclear Proteins / metabolism*
  • Protein Binding
  • Replication Origin
  • Replication Protein A
  • S Phase
  • Saccharomyces cerevisiae / cytology
  • Saccharomyces cerevisiae / genetics*
  • Saccharomyces cerevisiae Proteins*

Substances

  • CDC45 protein, S cerevisiae
  • Carrier Proteins
  • Cell Cycle Proteins
  • DNA, Fungal
  • DNA-Binding Proteins
  • Nuclear Proteins
  • Replication Protein A
  • Saccharomyces cerevisiae Proteins
  • Sld3 protein, S cerevisiae