Michael W M, Newport J
Department of Biology, University of California, San Diego, La Jolla, CA 92093-0347, USA.
Science. 1998 Dec 4;282(5395):1886-9. doi: 10.1126/science.282.5395.1886.
The dependence of mitosis on the completion of the period of DNA replication in the cell cycle [synthesis (S) phase] ensures that chromosome segregation occurs only after the genome has been fully duplicated. A key negative regulator of mitosis, the protein kinase Wee1, was degraded in a Cdc34-dependent fashion in Xenopus egg extracts. This proteolysis event was required for a timely entrance into mitosis and was inhibited when DNA replication was blocked. Therefore, the DNA replication checkpoint can prevent mitosis by suppressing the proteolysis of Wee1 during S phase.
有丝分裂对细胞周期中DNA复制期（合成期，即S期）完成的依赖性确保了染色体分离仅在基因组完全复制之后才会发生。有丝分裂的一个关键负调控因子，即蛋白激酶Wee1，在非洲爪蟾卵提取物中以Cdc34依赖性方式被降解。这种蛋白水解事件是及时进入有丝分裂所必需的，并且当DNA复制受阻时会受到抑制。因此，DNA复制检查点可以通过在S期抑制Wee1的蛋白水解来阻止有丝分裂。
