Human Mcm10 regulates the catalytic subunit of DNA polymerase-α and prevents DNA damage during replication
Human Mcm10 regulates the catalytic subunit of DNA polymerase-α and prevents DNA damage during replication
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DOI：
10.1091/mbc.e06-12-1148
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发表时间：
2007-10-01
影响因子：
3.3
通讯作者：
Bielinsky, Anja-Katrin
中科院分区：
文献类型：
--
作者：
Chattopadhyay, Sharbani;Bielinsky, Anja-Katrin
在酿酒酵母中，微小染色体维持蛋白（Mcm）10与DNA聚合酶（pol）-α相互作用，并作为催化亚基的核伴侣发挥作用，该催化亚基在没有Mcm 10的情况下迅速降解。我们在这里报告说，Mcm 10和pol-alpha之间的相互作用是保守的人类细胞。我们使用了一种基于小干扰RNA的方法来耗尽HeLa细胞中的Mcm 10，我们观察到pol-alpha的催化亚基p180以与Mcm 10相似的动力学降解，而调节pol-alpha亚基p68则不受影响。Mcm 10和p180的同时丢失抑制S期进入，并导致已经复制的细胞在S/G2晚期的积累，作为DNA损伤的结果，这引发了细胞亚群的凋亡。这些表型与果蝇胚胎细胞中没有表现出类似停滞的类似研究有很大不同。为了进一步剖析Mcm 10和p180在人类细胞中的作用，我们单独耗尽p180，并观察到S期进入和分叉进展的显著延迟，但对细胞活力的影响很小。这些结果表明，细胞可以容忍低水平的p180，只要Mcm 10是存在的“回收”它。因此，人类Mcm 10调节复制起始和延伸，并保持基因组的完整性。
In Saccharomyces cerevisiae, minichromosome maintenance protein (Mcm) 10 interacts with DNA polymerase (pol)-alpha and functions as a nuclear chaperone for the catalytic subunit, which is rapidly degraded in the absence of Mcm10. We report here that the interaction between Mcm10 and pol-alpha is conserved in human cells. We used a small interfering RNA-based approach to deplete Mcm10 in HeLa cells, and we observed that the catalytic subunit of pol-alpha, p180, was degraded with similar kinetics as Mcm10, whereas the regulatory pol-alpha subunit, p68, remained unaffected. Simultaneous loss of Mcm10 and p180 inhibited S phase entry and led to an accumulation of already replicating cells in late S/G2 as a result of DNA damage, which triggered apoptosis in a subpopulation of cells. These phenotypes differed considerably from analogous studies in Drosophila embryo cells that did not exhibit a similar arrest. To further dissect the roles of Mcm10 and p180 in human cells, we depleted p180 alone and observed a significant delay in S phase entry and fork progression but little effect on cell viability. These results argue that cells can tolerate low levels of p180 as long as Mcm10 is present to "recycle" it. Thus, human Mcm10 regulates both replication initiation and elongation and maintains genome integrity.