Labib K, Diffley J F, Kearsey S E
ICRF Clare Hall Laboratories, South Mimms, Hertfordshire, EN6 3LD, UK.
Nat Cell Biol. 1999 Nov;1(7):415-22. doi: 10.1038/15649.
Cyclin-dependent kinases (CDKs) activate the firing of replication origins during the S phase of the cell cycle. They also block re-initiation of DNA replication within a single cell cycle, by preventing the assembly of prereplicative complexes at origins. We show here that, in budding yeast, CDKs exclude the essential prereplicative-complex component Mcm4 from the nucleus. Although origin firing can be triggered by the B-type cyclins only, both G1-phase and B-type cyclins cause exit of Mcm4 from the nucleus. These results suggest that G1 cyclins may diminish the cell's capacity to assemble prereplicative complexes before B-type cyclins trigger origin firing during S phase.
细胞周期蛋白依赖性激酶（CDKs）在细胞周期的S期激活复制起点的启动。它们还通过阻止复制起点处前复制复合物的组装，来阻止单个细胞周期内DNA复制的重新启动。我们在此表明，在芽殖酵母中，CDKs将前复制复合物的必需组分Mcm4排除在细胞核之外。虽然只有B型细胞周期蛋白能触发复制起点的启动，但G1期细胞周期蛋白和B型细胞周期蛋白都会导致Mcm4从细胞核中排出。这些结果表明，在B型细胞周期蛋白在S期触发复制起点启动之前，G1期细胞周期蛋白可能会降低细胞组装前复制复合物的能力。
