Integral membrane proteins of the nuclear envelope are dispersed throughout the endoplasmic reticulum during mitosis.
Integral membrane proteins of the nuclear envelope are dispersed throughout the endoplasmic reticulum during mitosis.
复制标题
核包膜的整体膜蛋白在有丝分裂过程中分散在整个内质网中。
DOI：
10.1083/jcb.137.6.1199
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发表时间：
1997-06-16
影响因子：
7.8
通讯作者：
Gerace, L
中科院分区：
文献类型：
--
作者：
Yang, L;Guan, T;Gerace, L
我们分析了培养的哺乳动物细胞有丝分裂过程中核膜的几种完整膜蛋白的命运，以确定核膜蛋白在有丝分裂核膜解体后是存在于有丝分裂后不同于整体内质网的囊泡中，还是分散在整个内质网中。应用免疫荧光染色和共聚焦显微镜技术，我们比较了两种核膜蛋白(层相关多肽1和2[LAP1和LAP2])和核孔膜蛋白(Gp210)的定位，以及用脂类染料(DiOC6和R6)和多克隆抗体测定的块状ER膜的分布。我们发现，在这项技术的分辨率下，在有丝分裂过程中，这三个核膜标记完全分散在整个ER膜上。与这些结果一致的是，我们通过中期细胞的免疫金电子显微镜在大多数含有ER标记的膜上检测到LAP1。总之，这些发现表明，核膜在有丝分裂过程中失去了作为内质网亚室的身份。我们发现核膜蛋白在有丝分裂结束时与LAP1和LAP2同时开始在染色体周围重组，并提出在有丝分裂结束时核膜的重组涉及到通过与核膜蛋白和染色质的结合将完整的膜蛋白分离到染色体表面。
We have analyzed the fate of several integral membrane proteins of the nuclear envelope during mitosis in cultured mammalian cells to determine whether nuclear membrane proteins are present in a vesicle population distinct from bulk ER membranes after mitotic nuclear envelope disassembly or are dispersed throughout the ER. Using immunofluorescence staining and confocal microscopy, we compared the localization of two inner nuclear membrane proteins (laminaassociated polypeptides 1 and 2 [LAP1 and LAP2]) and a nuclear pore membrane protein (gp210) to the distribution of bulk ER membranes, which was determined with lipid dyes (DiOC6 and R6) and polyclonal antibodies. We found that at the resolution of this technique, the three nuclear envelope markers become completely dispersed throughout ER membranes during mitosis. In agreement with these results, we detected LAP1 in most membranes containing ER markers by immunogold electron microscopy of metaphase cells. Together, these findings indicate that nuclear membranes lose their identity as a subcompartment of the ER during mitosis. We found that nuclear lamins begin to reassemble around chromosomes at the end of mitosis at the same time as LAP1 and LAP2 and propose that reassembly of the nuclear envelope at the end of mitosis involves sorting of integral membrane proteins to chromosome surfaces by binding interactions with lamins and chromatin.