DNA synthesis at individual replication forks requires the essential initiation factor Cdc45p
DNA synthesis at individual replication forks requires the essential initiation factor Cdc45p
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DOI：
10.1093/emboj/19.9.2082
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发表时间：
2000-05-02
期刊：
影响因子：
11.4
通讯作者：
Diffley, JFX
中科院分区：
文献类型：
--
作者：
Tercero, JA;Labib, K;Diffley, JFX
Cdc45p 在起始前在复制起点处组装，并且是酿酒酵母中起点激发所必需的。构建了热诱导的 cdc45 降解决定子突变体，其在限制温度下促进 Cdc45p 的快速降解。与起始中的作用一致，G(I) 中 Cdc45p 的丢失会阻止所有可检测的 DNA 复制，而不阻止随后进入有丝分裂。S 期期间 Cdc45p 活性的丢失会阻止 S 期完成，但不会阻止复制检查点的激活。使用密度替代，我证明在允许复制叉建立后，Cdc45p 失活会阻止单个复制叉的后续进展，这提供了第一个直接的功能证据，证明 Cdc45p 在延伸过程中发挥重要作用。因此，与 SV40 复制中的大 T 抗原一样，Cdc45p 在染色体 DNA 复制的起始阶段和延伸阶段都发挥着核心作用。
Cdc45p assembles at replication origins before initiation and is required for origin firing in Saccharomyces cerevisiae. A heat-inducible cdc45 degron mutant was constructed that promotes rapid degradation of Cdc45p at the restrictive temperature, Consistent with a role in initiation, loss of Cdc45p in G(I) prevents all detectable DNA replication without preventing subsequent entry into mitosis, Loss of Cdc45p activity during S-phase blocks S-phase completion but not activation of replication checkpoints. Using density substitution, me show that after allowing replication fork establishment, Cdc45p inactivation prevents the subsequent progression of individual replication forks, This provides the first direct functional evidence that Cdc45p plays an essential role during elongation. Thus, like the large T antigen in SV40 replication, Cdc45p plays a central role in both initiation and elongation phases of chromosomal DNA replication.