MAN1 and emerin have overlapping function(s) essential for chromosome segregation and cell division in Caenorhabditis elegans
MAN1 and emerin have overlapping function(s) essential for chromosome segregation and cell division in Caenorhabditis elegans
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DOI：
10.1073/pnas.0730821100
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发表时间：
2003-04-15
影响因子：
11.1
通讯作者：
Gruenbaum, Y
中科院分区：
文献类型：
--
作者：
Liu, J;Lee, KK;Gruenbaum, Y
Emerin和MAN 1是脊椎动物核膜中含有LEM结构域的膜蛋白。MAN 1的功能尚不清楚，而emerin已知与核纤层蛋白、屏障-自动整合因子（BAF）、nesprin-1 α和转录抑制因子相互作用。Emerin突变导致X连锁隐性Emery-Dreifuss肌营养不良症。Emerin和MAN 1同源物在秀丽隐杆线虫中都是保守的，但Ce-emerin的缺失没有可检测的表型。因此，我们使用线虫来测试Ce-MAN 1与Ce-emerin功能重叠的假设。支持这一模型，Ce-MAN 1直接相互作用与Ce-核纤层蛋白和Ce-BAF在体外，并需要Ce-核纤层蛋白的核膜定位。有趣的是，RNA干扰介导的Ce-MAN 1去除约90%对约15%的胚胎是致命的。然而，在没有Ce-emerin的情况下，Ce-MAN 1的大约90%的减少对100细胞期的所有胚胎都是致命的，其表型涉及后期染色体桥接和胞质分裂的重复循环[“细胞不合时宜地撕裂”（切割）表型]。免疫染色显示，后期桥接的染色质特异性保留有丝分裂特异性磷酸化组蛋白H3表位，并未能招募可检测的Ce-层蛋白或Ce-BAF。这些发现表明LEM结构域蛋白对于细胞分裂是必需的，并且Ce-emerin和Ce-MAN 1共享至少一个和可能多个重叠的功能，这可能与Emery-Dreifuss肌营养不良症相关。
Emerin and MAN1 are LEM domain-containing integral membrane proteins of the vertebrate nuclear envelope. The function of MAN1 is unknown, whereas emerin is known to interact with nuclear lamins, barrier-to-auto integration factor (BAF), nesprin-1alpha, and a transcription repressor. Mutations in emerin cause X-linked recessive Emery-Dreifuss muscular dystrophy. Emerin and MAN1 homologs are both conserved in Caenorhabditis elegans, but loss of Ce-emerin has no detectable phenotype. We therefore used C elegans to test the hypothesis that Ce-MAN1 overlaps functionally with Ce-emerin. Supporting this model, Ce-MAN1 interacted directly with Ce-lamin and Ce-BAF in vitro and required Ce-lamin for its nuclear envelope localization. Interestingly, RNA interference-mediated removal of approximate to90% of Ce-MAN1 was lethal to approximate to15% of embryos. However, in the absence of Ce-emerin, approximate to90% reduction of Ce-MAN1 was lethal to all embryos by the 100-cell stage, with a phenotype involving repeated cycles of anaphase chromosome bridging and cytokinesis ["cell untimely torn" (cut) phenotype]. Immunostaining showed that the anaphase-bridged chromatin specifically retained a mitosis-specific phosphohistone H3 epitope and failed to recruit detectable Ce-lamin or Ce-BAF. These findings show that LEM domain proteins are essential for cell division and that Ce-emerin and Ce-MAN1 share at least one and possibly multiple overlapping functions, which may be relevant to Emery-Dreifuss muscular dystrophy.