Te12 is required for activation of the Mrc1-mediated replication checkpoint
Te12 is required for activation of the Mrc1-mediated replication checkpoint
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DOI：
10.1074/jbc.m607432200
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发表时间：
2007-02-23
影响因子：
4.8
通讯作者：
Kanoh, Junko
中科院分区：
文献类型：
--
作者：
Shikata, Miho;Ishikawa, Fuyuki;Kanoh, Junko
属于Tel 2/Rad-5/Clk-2家族的蛋白质在真核生物中是保守的，并且参与各种细胞过程，例如细胞增殖、端粒维持、生物钟和DNA损伤检查点。然而，这些分子的功能背后的分子机制在很大程度上仍然不清楚。在这里，我们报告说，在裂殖酵母，裂殖酵母，Te 12是必需的有效磷酸化Mrc 1，DNA复制检查点信号的介质，并激活Cds 1，复制检查点激酶，当DNA复制被阻断由羟基脲。事实上，Tel 2是复制叉停滞的存活和缺乏Chk 1的细胞中的复制检查点所必需的，Chk 1是另一种检查点激酶，其作用与复制阻断引起的细胞周期停滞中的Cds 1的作用重叠。此外，Tel 2在进入S期和基因组稳定性中起重要作用。Tel 2是营养细胞生长所必需的，并且tel 2A菌株在萌发后积累具有IC DNA含量的细胞。在没有羟基脲的情况下，Tel 2在缺乏Swil的突变体中是至关重要的，Swil是复制叉保护复合物的一个组分，并且在Tel 2抑制的Swil A细胞中经常观察到多个Rad 22 DNA修复灶，特别是在S期。相反，cds 1 Delta swil Delta突变体没有显示出这种致死性。这些结果表明S.粟酒裂殖酵母Tel 2在Mrc 1介导的复制检查点中以及在基因组完整性的不依赖于Cds 1的调节中起重要作用。
Proteins belonging to the Tel2/Rad-5/Clk-2 family are conserved among eukaryotes and are involved in various cellular processes, such as cell proliferation, telomere maintenance, the biological clock, and the DNA damage checkpoint. However, the molecular mechanisms underlying the functions of these molecules remain largely unclear. Here we report that in the fission yeast, Schizosaccharomycespombe, Te12 is required for efficient phosphorylation of Mrc1, a mediator of DNA replication checkpoint signaling, and for activation of Cds1, a replication checkpoint kinase, when DNA replication is blocked by hydroxyurea. In fact, Tel2 is required for survival of replication fork arrest and for the replication checkpoint in cells lacking Chk1, another checkpoint kinase the role of which overlaps that of Cds1 in cell cycle arrest by replication block. in addition, Tel2 plays important roles in entry into S phase and in genome stability. Tel2 is essential for vegetative cell growth, and the tel2A strain accumulated cells with IC DNA content after germination. In the absence of hydroxyurea, Tel2 is vital in the mutant lacking Swil, a component of the replication fork protection complex, and multiple Rad22 DNA repair foci were frequently observed in Tel2-repressed swil A cells especially at S phase. In contrast, the cds1 Delta swi1 Delta mutant did not show such lethality. These results indicate that S. pombe Tel2 plays important roles in the Mrc1-mediated replication checkpoint as well as in the Cds1-independent regulation of genome integrity.