Identification of Conserved MEL-28/ELYS Domains with Essential Roles in Nuclear Assembly and Chromosome Segregation.
Identification of Conserved MEL-28/ELYS Domains with Essential Roles in Nuclear Assembly and Chromosome Segregation.
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DOI：
10.1371/journal.pgen.1006131
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发表时间：
2016-06
期刊：
影响因子：
4.5
通讯作者：
Askjaer P
中科院分区：
文献类型：
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作者：
Gómez-Saldivar G;Fernandez A;Hirano Y;Mauro M;Lai A;Ayuso C;Haraguchi T;Hiraoka Y;Piano F;Askjaer P
核孔蛋白是核孔复合体的组成成分，是核质转运、基因表达和基因组稳定性的重要调节因子。核孔蛋白Mel-28/Elys通过募集NUP107-160亚复合体在有丝分裂后NPC重组中发挥关键作用，并且是有丝分裂染色体正确分离所必需的。在这里，我们提出了一个系统的功能和结构分析的MEL-28在线虫的早期发育和培养细胞中的人Elys。我们已经确定了负责核膜和动粒定位、染色质结合、有丝分裂纺锤体基质结合和染色体分离的功能结构域。令人惊讶的是，我们发现对MEL-28‘S保守AT-钩区的扰动并不影响MEL-28的定位，尽管它们以依赖于DNA损伤检查点的方式扰乱了MEL-28的功能并延迟了细胞周期的进展。我们的分析还揭示了MEL-28的一个新的减数分裂作用。综上所述，这些结果表明MEL-28具有保守的结构域，这些结构域对于其在NPC组装和染色体分离中的基础作用是必不可少的。大多数动物细胞都有一个含有遗传物质的细胞核：染色体。细胞核被核膜包围，核膜在染色体和周围的细胞质之间提供了物理屏障，使蛋白质能够精确地控制进出细胞核的运输。转运通过核孔复合体进行，这种复合体由约30种不同蛋白质的多个拷贝组成，称为核孔蛋白。虽然核孔复合体的组成是已知的，但它们的组装和功能的机制仍然不清楚。我们通过系统地剖析线虫和人类细胞中的功能结构域，分析了核孔蛋白Mel-28/Elys。有趣的是，Mel-28/Elys不仅定位于核孔复合体，而且与细胞分裂过程中被称为动点的染色体结构有关。我们的研究表明，MEL-28/ELYS中即使是很小的扰动也会对核孔复合体的组装以及细胞分裂过程中染色体的分离产生重大影响。令人惊讶的是，抑制Mel-28/Elys会导致细胞周期延迟，这表明激活了染色体损伤的细胞监测系统。最后，我们得出结论：MEL-28/Elys的结构域从线虫到人类都是保守的。
Nucleoporins are the constituents of nuclear pore complexes (NPCs) and are essential regulators of nucleocytoplasmic transport, gene expression and genome stability. The nucleoporin MEL-28/ELYS plays a critical role in post-mitotic NPC reassembly through recruitment of the NUP107-160 subcomplex, and is required for correct segregation of mitotic chromosomes. Here we present a systematic functional and structural analysis of MEL-28 in C. elegans early development and human ELYS in cultured cells. We have identified functional domains responsible for nuclear envelope and kinetochore localization, chromatin binding, mitotic spindle matrix association and chromosome segregation. Surprisingly, we found that perturbations to MEL-28’s conserved AT-hook domain do not affect MEL-28 localization although they disrupt MEL-28 function and delay cell cycle progression in a DNA damage checkpoint-dependent manner. Our analyses also uncover a novel meiotic role of MEL-28. Together, these results show that MEL-28 has conserved structural domains that are essential for its fundamental roles in NPC assembly and chromosome segregation. Most animal cells have a nucleus that contains the genetic material: the chromosomes. The nucleus is enclosed by the nuclear envelope, which provides a physical barrier between the chromosomes and the surrounding cytoplasm, and enables precisely controlled transport of proteins into and out of the nucleus. Transport occurs through nuclear pore complexes, which consist of multiple copies of ~30 different proteins called nucleoporins. Although the composition of nuclear pore complexes is known, the mechanisms of their assembly and function are still unclear. We have analyzed the nucleoporin MEL-28/ELYS through a systematic dissection of functional domains both in the nematode Caenorhabditis elegans and in human cells. Interestingly, MEL-28/ELYS localizes not only to nuclear pore complexes, but is also associated with chromosomal structures known as kinetochores during cell division. Our studies have revealed that even small perturbations in MEL-28/ELYS can have dramatic consequences on nuclear pore complex assembly as well as on separation of chromosomes during cell division. Surprisingly, inhibition of MEL-28/ELYS causes cell-cycle delay, suggesting activation of a cellular surveillance system for chromosomal damages. Finally, we conclude that the structural domains of MEL-28/ELYS are conserved from nematodes to humans.