A Missense Mutation in Rev7 Disrupts Formation of Polζ, Impairing Mouse Development and Repair of Genotoxic Agent-induced DNA Lesions
A Missense Mutation in Rev7 Disrupts Formation of Polζ, Impairing Mouse Development and Repair of Genotoxic Agent-induced DNA Lesions
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DOI：
10.1074/jbc.m113.514752
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发表时间：
2014-02-07
影响因子：
4.8
通讯作者：
Kunieda, Tetsuo
中科院分区：
文献类型：
--
作者：
Khalaj, Maryam;Abbasi, Abdolrahim;Kunieda, Tetsuo
背景：Rev 7编码Pol的一个亚基，用于跨损伤DNA合成（TLS）。结果：我们在小鼠中发现了Rev 7突变，该突变导致发育缺陷并增加了对遗传毒性的易感性。结论：Rev 7通过其在细胞增殖中的功能对小鼠发育是必需的。意义：这些发现证明了Pol在发育中的独特功能，这在其他TLS聚合酶中不存在。Repro 22是一种通过N-乙基-N-亚硝基脲诱导的诱变产生的突变小鼠，其表现出不育性，伴有由原始生殖细胞增殖缺陷、体重下降和胚胎发育期间的部分致死性引起的生殖细胞耗竭。使用位置克隆策略，我们确定了一个错义突变在Rev 7/Mad 2l 2（Rev 7（C70 R）），并证实该突变是缺陷的原因在repro 22小鼠通过转基因救援与正常的Rev 7。Rev 7/Mad 2l 2编码DNA聚合酶（Pol）的亚基，DNA聚合酶是哺乳动物中已知的10种跨损伤DNA合成聚合酶之一。突变体REV 7不与Pol.Rev7（C70 R/C70 R）细胞的催化亚基REV 3相互作用，显示增殖降低、凋亡增加和S期阻滞，细胞核中存在广泛的H2 AX灶，表明用遗传毒性剂丝裂霉素C处理后DNA损伤累积。Rev 7（C70 R）突变不影响有丝分裂纺锤体组装检查点。这些结果表明Rev 7在解决S期DNA损伤引起的复制停滞中是必不可少的。我们得出结论，Rev 7是原始生殖细胞增殖和胚胎活力和发展所需的，通过跨病变DNA合成活性的Pol保持DNA完整性，在细胞增殖过程中，这是需要在高度增殖的胚胎细胞。
Background:Rev7 encodes a subunit of Pol for translesion DNA synthesis (TLS). Results: We found a Rev7 mutation in mice that causes developmental defects and increases susceptibility for genotoxicity. Conclusion:Rev7 is essential for mouse development through its function in cell proliferation. Significance: These findings demonstrate a unique function of Pol in development that is absent in other TLS polymerases. Repro22 is a mutant mouse produced via N-ethyl-N-nitrosourea-induced mutagenesis that shows sterility with germ cell depletion caused by defective proliferation of primordial germ cells, decreased body weight, and partial lethality during embryonic development. Using a positional cloning strategy, we identified a missense mutation in Rev7/Mad2l2 (Rev7(C70R)) and confirmed that the mutation is the cause of the defects in repro22 mice through transgenic rescue with normal Rev7. Rev7/Mad2l2 encodes a subunit of DNA polymerase (Pol), 1 of 10 translesion DNA synthesis polymerases known in mammals. The mutant REV7 did not interact with REV3, the catalytic subunit of Pol. Rev7(C70R/C70R) cells showed decreased proliferation, increased apoptosis, and arrest in S phase with extensive H2AX foci in nuclei that indicated accumulation of DNA damage after treatment with the genotoxic agent mitomycin C. The Rev7(C70R) mutation does not affect the mitotic spindle assembly checkpoint. These results demonstrated that Rev7 is essential in resolving the replication stalls caused by DNA damage during S phase. We concluded that Rev7 is required for primordial germ cell proliferation and embryonic viability and development through the translesion DNA synthesis activity of Pol preserving DNA integrity during cell proliferation, which is required in highly proliferating embryonic cells.