C-elegans nuclear envelope proteins emerin, MAN1, lamin, and nucleoporins reveal unique timing of nuclear envelope breakdown during mitosis
C-elegans nuclear envelope proteins emerin, MAN1, lamin, and nucleoporins reveal unique timing of nuclear envelope breakdown during mitosis
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DOI：
10.1091/mbc.11.9.3089
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发表时间：
2000-09-01
影响因子：
3.3
通讯作者：
Wilson, KL
中科院分区：
文献类型：
--
作者：
Lee, KK;Gruenbaum, Y;Wilson, KL
Emerin、MAN1 和 LAP2 是脊椎动物核膜的整合膜蛋白。它们共享一个 43 个残基的 N 端基序，称为 LEM 结构域。我们在秀丽隐杆线虫中发现了三个假定的 LEM 结构域基因，分别命名为 emr-1、lem-2 和 lem-3。我们分析了编码 Ce-emerin 的 emr-1 和编码 Ce-MAN1 的 lem-2。 Ce-emerin 和 Ce-MAN1 在 SDS-PAGE 上分别作为 17 kDa 和 52 kDa 蛋白迁移。基于其生化提取特性和免疫定位，Ce-emerin 和 Ce-MAN1 都是定位于核膜的整合膜蛋白。我们使用针对 Ce-MAN1、Ce-emerin、核孔蛋白和 Ce-lamin 的抗体来确定线虫有丝分裂期间核膜破裂的时间。与脊椎动物和果蝇相比，线虫的核膜分解得非常晚。在中期和后期早期，除纺锤体极附近外，核膜在各处均保持完整，仅在后期中后期完全分解。孔复合物的分解，以及较小程度的层板的分解，取决于胚胎年龄：在>30细胞胚胎的中期，孔复合物不存在，但在2至24细胞胚胎中，孔复合物一直存在到后期。核内 mRNA 剪接因子在前期后分解。线虫的核分解时间是新颖的，可能反映了它在单细胞和更复杂的真核生物之间的进化地位。
Emerin, MAN1, and LAP2 are integral membrane proteins of the vertebrate nuclear envelope. They share a 43-residue N-terminal motif termed the LEM domain. We found three putative LEM domain genes in Caenorhabditis elegans, designated emr-1, lem-2, and lem-3. We analyzed emr-1, which encodes Ce-emerin, and lem-2, which encodes Ce-MAN1. Ce-emerin and Ce-MAN1 migrate on SDS-PAGE as 17- and 52-kDa proteins, respectively. Based on their biochemical extraction properties and immunolocalization, both Ce-emerin and Ce-MAN1 are integral membrane proteins localized at the nuclear envelope. We used antibodies against Ce-MAN1, Ce-emerin, nucleoporins, and Ce-lamin to determine the timing of nuclear envelope breakdown during mitosis in C. elegans. The C. elegans nuclear envelope disassembles very late compared with vertebrates and Drosophila. The nuclear membranes remained intact everywhere except near spindle poles during metaphase and early anaphase, fully disassembling only during mid-late anaphase. Disassembly of pore complexes, and to a lesser extent the lamina, depended on embryo age: pore complexes were absent during metaphase in >30-cell embryos but existed until anaphase in 2- to 24-cell embryos. Intranuclear mRNA splicing factors disassembled after prophase. The timing of nuclear disassembly in C. elegans is novel and may reflect its evolutionary position between unicellular and more complex eukaryotes.