Reference - PMID:12186947 - A novel chk1-dependent G1/M checkpoint in fission yeast.
Reference summary
- PubMed ID
- PMID:12186947
- Title
- A novel chk1-dependent G1/M checkpoint in fission yeast.
- Authors
- Synnes M, Nilssen EA, Boye E, Grallert B
- Citation
- J Cell Sci 2002 Sep 15;115(Pt 18):3609-18
- Publication year
- 2002
- Abstract
- Fission yeast cells with a temperature-sensitive Orp1 protein, a component of the origin recognition complex, cannot perform DNA replication at the restrictive temperature. Seventy percent of orp1-4 cells arrest with a 1C DNA content, whereas 30% proceed to mitosis ('cut'). The arrest depends upon the checkpoint Rad proteins and, surprisingly, the Chk1 protein, which is thought to act only from late S phase. The arrested cells maintain a 1C DNA content, as judged by flow cytometry, and the early origin ars3001 has not been initiated, as judged by 2D gel analysis. We show that in G1-arrested orp1-4 cells, Wee1 phosphorylates and inactivates Cdc2. Activation of Chk1 occurs earlier than Cdc2 phosphorylation, indicating a novel role for Chk1, namely to induce and/or maintain Cdc2 phosphorylation upon checkpoint activation in G1. We also show that commitment to cutting occurs already in early G1 phase.
