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S-phase checkpoint controls mitosis via an APC-independent Cdc20p function
Duncan J Clarke1, Marisa Segal, Catherine A Andrews
1The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, California 92037, USA.
Nature Cell Biology
|September 23, 2003
Summary
Budding yeast Mec1p and Rad53p prevent mitosis during DNA replication by repressing Cdc20p accumulation. This ensures precise regulation of cell division, avoiding genomic instability and cancer-associated abnormalities.
Area of Science:
- Cell Biology
- Molecular Biology
- Genetics
Background:
- Cell cycle checkpoints are crucial for preventing genomic instability, a hallmark of cancer.
- S-phase checkpoints halt cell division during DNA replication to ensure accurate genome duplication.
- The roles of budding yeast Mec1p and Rad53p (homologues of ATM/ATR and Chk2) in preventing mitosis during S phase are not fully understood.
Purpose of the Study:
- To elucidate the mechanism by which Mec1p and Rad53p prevent mitosis during S phase in budding yeast.
- To investigate the role of Cdc20p regulation in this process.
Main Methods:
- The study utilized budding yeast as a model organism.
- Investigated the regulation of Cdc20p accumulation by Mec1p and Rad53p during S phase.
- Examined the consequences of precocious Cdc20p accumulation on anaphase onset and aneuploidy.
Main Results:
- Mec1p and Rad53p were found to repress the accumulation of Cdc20p during S phase.
- Precocious accumulation of Cdc20p leads to premature anaphase onset and aneuploidy.
- Cdc20p can induce mitosis even without core anaphase-promoting complex (APC) components.
Conclusions:
- Budding yeast prevents mitosis during S phase by regulating Cdc20p levels via Mec1p and Rad53p.
- Precise control of Cdc20p concentration is essential for cell cycle fidelity.
- Cdc20p plays a critical role in mitosis, potentially functioning independently of the APC.