An essential role for Drosophila hus1 in somatic and meiotic DNA damage responses
An essential role for Drosophila hus1 in somatic and meiotic DNA damage responses
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DOI：
10.1242/jcs.03414
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发表时间：
2007-03-15
影响因子：
4
通讯作者：
Schupbach, Trudi
中科院分区：
文献类型：
--
作者：
Abdu, Uri;Klovstad, Martha;Schupbach, Trudi
检查点蛋白 Rad9、Rad1 和 Hus1 形成钳状复合物，在 DNA 损伤诱导的检查点反应中发挥核心作用。在这里，我们讨论果蝇中 9-1-1 复合体的功能。我们决定将分析重点放在 hus1 的减数分裂和体细胞要求上。为此，我们通过不精确切除距 hus1 基因 3' 2 kb 处的 P 元件，创建了 hus1 的无效等位基因。我们发现 hus1 突变果蝇能够存活，但雌性不育。我们确定 hus1 突变果蝇对羟基脲和甲磺酸甲酯敏感，但对 X 射线不敏感，这表明 hus1 是激活 S 期检查点所必需的。我们还发现 hus1 不是 G2-M 检查点和辐射后诱导细胞凋亡所必需的。我们随后研究了 hus1 在减数分裂检查点激活中的作用，发现 hus1 突变抑制了 DNA 修复酶突变体引起的背腹缺陷。有趣的是，我们发现 hus1 突变体表现出与 DNA 修复酶突变产生的卵母细胞核缺陷相似的缺陷。这些结果表明，hus1 对于减数分裂检查点的激活至关重要，并且 hus1 对于卵母细胞 DNA 的组织也是必需的，该功能可能独立于减数分裂检查点。
The checkpoint proteins Rad9, Rad1 and Hus1 form a clamp-like complex which plays a central role in the DNA-damage-induced checkpoint response. Here we address the function of the 9-1-1 complex in Drosophila. We decided to focus our analysis on the meiotic and somatic requirements of hus1. For that purpose, we created a null allele of hus1 by imprecise excision of a P element found 2 kb from the 3' of the hus1 gene. We found that hus1 mutant flies are viable, but the females are sterile. We determined that hus1 mutant flies are sensitive to hydroxyurea and methyl methanesulfonate but not to X-rays, suggesting that hus1 is required for the activation of an S-phase checkpoint. We also found that hus1 is not required for the G2-M checkpoint and for post-irradiation induction of apoptosis. We subsequently studied the role of hus1 in activation of the meiotic checkpoint and found that the hus1 mutation suppresses the dorsal-ventral pattering defects caused by mutants in DNA repair enzymes. Interestingly, we found that the hus1 mutant exhibits similar oocyte nuclear defects as those produced by mutations in DNA repair enzymes. These results demonstrate that hus1 is essential for the activation of the meiotic checkpoint and that hus1 is also required for the organization of the oocyte DNA, a function that might be independent of the meiotic checkpoint.