Mutation of the zebrafish nucleoporin elys sensitizes tissue progenitors to replication stress.
Mutation of the zebrafish nucleoporin elys sensitizes tissue progenitors to replication stress.
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DOI：
10.1371/journal.pgen.1000240
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发表时间：
2008-10
期刊：
影响因子：
4.5
通讯作者：
Pack M
中科院分区：
文献类型：
--
作者：
Davuluri G;Gong W;Yusuff S;Lorent K;Muthumani M;Dolan AC;Pack M
隐性致死突变 flette lotte (flo) 会破坏斑马鱼消化系统和其他组织的发育。我们发现 flo 编码 Mel-28/Elys 的直向同源基因，这是一种高度保守的基因，已被证明是蠕虫细胞核完整性以及两栖动物和哺乳动物细胞核孔复合体 (NPC) 组装所必需的。当缺乏核孔的增殖组织中的细胞经历细胞周期停滞和凋亡时，母体 elys 表达将斑马鱼 flo 突变体维持到幼虫阶段。 p53 突变可以挽救视网膜和视顶盖的细胞凋亡，但不能挽救肠道中的细胞凋亡，因为检查点激酶 Chk2 在肠道中被激活。 DNA 合成抑制剂诱导的 Chk2 抑制和复制应激对花幼虫是致命的。相比之下，flo 突变体对导致 DNA 双链断裂的试剂不敏感，因此表明 Elys 的缺失会破坏对选定复制抑制剂的反应。 Elys 结合来自非洲爪蟾卵提取物的 Mcm2-7 复合物。 elys 突变减少了 Flo 肠道中 Mcm2 染色质的结合，但不减少 Mcm3 或 Mcm4 的结合。这些体内数据表明 Elys 在 Mcm2-染色质相互作用中发挥作用。此外，他们支持最近提出的一个模型，在该模型中，暴露于复制压力的人类细胞的生存需要过量 Mcm2-7 许可的复制起点。 DNA 复制是一个复杂的过程，需要激活细胞周期检查点和 DNA 修复途径。真菌的遗传分析表明，核孔蛋白（构成核孔复合物 (NPC) 的蛋白质）在细胞对破坏细胞增殖或损伤 DNA 的物质的反应中发挥着重要作用。在这里，我们发现 Elys 核孔蛋白的突变会导致斑马鱼 flottlotte (flo) 突变体的肠道和其他组织中广泛的细胞凋亡。在缺乏 DNA 损伤标记 γH2X 的情况下，肠道细胞凋亡就会发生，并且在 flo 突变体中，染色质结合的 Mcm2（DNA 复制解旋酶的一个组成部分）的水平也有所降低。这些发现表明，flo 肠细胞无法修复内源性复制错误。与这一想法一致，flo 突变体对 DNA 复制抑制剂（如羟基脲、紫外线照射或顺铂）治疗高度敏感，但对导致 DNA 双链断裂的药物（如 γ-照射或喜树碱）治疗高度敏感。这些数据表明核孔蛋白在真核细胞复制应激的细胞反应中发挥保守作用。
The recessive lethal mutation flotte lotte (flo) disrupts development of the zebrafish digestive system and other tissues. We show that flo encodes the ortholog of Mel-28/Elys, a highly conserved gene that has been shown to be required for nuclear integrity in worms and nuclear pore complex (NPC) assembly in amphibian and mammalian cells. Maternal elys expression sustains zebrafish flo mutants to larval stages when cells in proliferative tissues that lack nuclear pores undergo cell cycle arrest and apoptosis. p53 mutation rescues apoptosis in the flo retina and optic tectum, but not in the intestine, where the checkpoint kinase Chk2 is activated. Chk2 inhibition and replication stress induced by DNA synthesis inhibitors were lethal to flo larvae. By contrast, flo mutants were not sensitized to agents that cause DNA double strand breaks, thus showing that loss of Elys disrupts responses to selected replication inhibitors. Elys binds Mcm2-7 complexes derived from Xenopus egg extracts. Mutation of elys reduced chromatin binding of Mcm2, but not binding of Mcm3 or Mcm4 in the flo intestine. These in vivo data indicate a role for Elys in Mcm2-chromatin interactions. Furthermore, they support a recently proposed model in which replication origins licensed by excess Mcm2-7 are required for the survival of human cells exposed to replication stress. DNA replication is a complex process that requires activation of cell cycle checkpoints and DNA repair pathways. Genetic analyses in fungi have suggested that nucleoporins, the proteins that make up the nuclear pore complex (NPC), play a role in the cellular response to agents that disrupt cell proliferation or damage DNA. Here we show that mutation of the Elys nucleoporin causes widespread apoptosis in the intestine and other tissues of zebrafish flotte lotte (flo) mutants. Intestinal apoptosis occurs in the absence of the DNA damage marker γH2X, and levels of chromatin bound Mcm2, a component of the DNA replication helicase, were also reduced in flo mutants. These findings suggested that flo intestinal cells cannot repair endogenous replication errors. Consistent with this idea, flo mutants were highly sensitized to treatment with DNA replication inhibitors such as hydroxyurea, UV irradiation, or cisplatin, but not agents that cause DNA double strand breaks, such as γ-irradiation or camptothecin. These data point to a conserved role for nucleoporins in the cellular response to replication stress in eukaryote cells.
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影响因子：
30.8
作者：
Bennett, CB;Lewis, LK;Resnick, MA
通讯作者：
Resnick, MA
影响因子：
64.5
作者：
Dobles, M;Liberal, V;Sorger, PK
通讯作者：
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影响因子：
10.5
作者：
Ge, Xin Quan;Jackson, Dean A;Blow, J Julian
通讯作者：
Blow, J Julian
影响因子：
82.9
作者：
Frappart, PO;Tong, WM;Wang, ZQ
通讯作者：
Wang, ZQ
DOI：
10.1073/pnas.84.21.7552
发表时间：
1987-11-01
影响因子：
11.1
作者：
DAVIS, LI;BLOBEL, G
通讯作者：
BLOBEL, G