Wuarin Jérôme, Buck Vicky, Nurse Paul, Millar Jonathan B A
Division of Yeast Genetics, National Institute for Medical Research, The Ridgeway, Mill Hill, London NW7 1AA, United Kingdom.
Cell. 2002 Nov 1;111(3):419-31. doi: 10.1016/s0092-8674(02)01042-5.
We show that in fission yeast the mitotic B type cyclin Cdc13/Cdc2 kinase associates with replication origins in vivo. This association is dependent on the origin recognition complex (ORC), is established as chromosomes are replicated, and is maintained during G2 and early mitosis. Cells expressing an orp2 (ORC2) allele that reduces binding of Cdc13 to replication origins are acutely prone to chromosomal reduplication. In synchronized endoreduplicating cells, following Cdc13 ablation, replication origins are coordinately licensed prior to each successive round of S phase with the same periodicity as in a normal cell cycle. Thus, ORC bound mitotic Cyclin B/Cdc2 kinase imposes the dependency of S phase on an intervening mitosis but not the temporal licensing of replication origins between each S phase.
我们发现，在裂殖酵母中，有丝分裂B型细胞周期蛋白Cdc13/Cdc2激酶在体内与复制起点相关联。这种关联依赖于起点识别复合物（ORC），随着染色体的复制而建立，并在G2期和有丝分裂早期维持。表达降低Cdc13与复制起点结合能力的orp2（ORC2）等位基因的细胞极易发生染色体再复制。在同步化的核内再复制细胞中，Cdc13缺失后，复制起点在每一轮连续的S期之前以与正常细胞周期相同的周期被协调许可。因此，与ORC结合的有丝分裂细胞周期蛋白B/Cdc2激酶使S期依赖于中间的有丝分裂，但不影响每个S期之间复制起点的时间许可。
