Sld3, which interacts with Cdc45 (Sld4), functions for chromosomal DNA replication in Saccharomyces cerevisiae
Sld3, which interacts with Cdc45 (Sld4), functions for chromosomal DNA replication in Saccharomyces cerevisiae
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DOI：
10.1093/emboj/20.8.2097
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发表时间：
2001-04-17
期刊：
影响因子：
11.4
通讯作者：
Araki, H
中科院分区：
文献类型：
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作者：
Kamimura, Y;Tak, YS;Araki, H
Cdc 45与微小染色体维持蛋白（Mcm）结合，在真核生物染色体DNA复制的起始和延伸过程中起关键作用。在这里，我们表明，在酿酒酵母的整个细胞周期中，Cdc 45形成一个新的因子，Sld 3，Consistent，Sld 3和Cdc 45同时与复制起点在染色质免疫沉淀试验中的复合物：这两种蛋白质与早期点火起点在G（1）相关联，并与后期点火起点在后期S相。此外，Sld 3和Cdc 45的起源关联是相互依赖的。温度敏感性突变Sld 3使限制性温度下的DNA复制缺陷，不仅降低了Sld 3与Cdc 45之间的相互作用，而且降低了Cdc 45与Mcm 2之间的相互作用。这些结果表明，Sld 3-Cdc 45复合物通过Mcm蛋白与复制起点相关联。在限制性温度下，Sld 3 -5细胞中的复制因子A，一种单链DNA结合蛋白，不与起点结合。因此，Sld 3-Cdc 45复合物的起始缔合是DNA复制起始中起始解旋的先决条件。
Cdc45, which binds to the minichromosomal maintenance (Mcm) proteins, has a pivotal role in the initiation and elongation steps of chromosomal DNA replication in eukaryotes. Here we show that throughout the cell cycle in Saccharomyces cerevisiae, Cdc45 forms a complex with a novel factor, Sld3, Consistently, Sld3 and Cdc45 associate simultaneously with replication origins in the chromatin immunoprecipitation assay: both proteins associate with early-firing origins in G(1) phase and with late-firing origins in late S phase. Moreover, the origin associations of Sld3 and Cdc45 are mutually dependent. The temperature-sensitive sld3 mutation confers a defect in DNA replication at the restrictive temperature and reduces an interaction not only between Sld3 and Cdc45, but also between Cdc45 and Mcm2, These results suggest that the Sld3-Cdc45 complex associates with replication origins through Mcm proteins. At the restrictive temperature in sld3-5 cells, replication factor A, a single-strand DNA binding protein, does not associate with origins. Therefore, the origin association of Sld3-Cdc45 complex is prerequisite for origin unwinding in the initiation of DNA replication.