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GINS, a novel multiprotein complex required for chromosomal DNA replication in budding yeast
Yuko Takayama1, Yoichiro Kamimura, Mariko Okawa
1Division of Microbial Genetics, National Institute of Genetics, Mishima, Shizuoka 411-8540, Japan.
Genes & Development
|May 6, 2003
Summary
A novel GINS complex is crucial for DNA replication in budding yeast. This complex, comprising Sld5, Psf1, Psf2, and Psf3, ensures proper assembly of replication proteins at origins for DNA synthesis initiation.
Area of Science:
- Molecular Biology
- Cell Cycle Regulation
- DNA Replication
Background:
- Eukaryotic DNA replication involves a two-step protein assembly process at replication origins.
- Formation of the prereplicative complex (pre-RC) in late M/G1 and subsequent assembly in S phase are critical for DNA synthesis.
- In budding yeast, Dpb11 and the Sld3-Cdc45 complex are known to be essential for DNA polymerase loading.
Purpose of the Study:
- To identify and characterize novel protein complexes involved in budding yeast DNA replication.
- To elucidate the role of the newly discovered GINS complex in the initiation of chromosomal DNA replication.
Main Methods:
- Conditional mutations in Sld5 and Psf1 were used to assess their role in DNA replication.
- Chromatin association of GINS, Dpb11, and Cdc45 was analyzed during S phase.
- Genetic and two-hybrid interaction studies were performed to investigate protein interactions.
Main Results:
- A novel conserved complex, GINS (Sld5, Psf1, Psf2, Psf3), was identified in budding yeast.
- GINS is essential for DNA replication, as indicated by replication defects in GINS mutants.
- GINS, Dpb11, Sld3, and Cdc45 assemble dependently at replication origins to initiate DNA synthesis.
Conclusions:
- The GINS complex plays a vital role in the initiation of chromosomal DNA replication in budding yeast.
- GINS acts in a mutually dependent manner with Dpb11, Sld3, and Cdc45 for proper replication origin assembly and DNA synthesis.