Nuclear shape, growth and integrity in the closed mitosis of fission yeast depend on the Ran-GTPase system, the spindle pole body and the endoplasmic reticulum
Nuclear shape, growth and integrity in the closed mitosis of fission yeast depend on the Ran-GTPase system, the spindle pole body and the endoplasmic reticulum
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DOI：
10.1242/jcs.049999
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发表时间：
2009-07-15
影响因子：
4
通讯作者：
Sazer, Shelley
中科院分区：
文献类型：
--
作者：
Gonzalez, Yanira;Meerbrey, Kristen;Sazer, Shelley
核膜 (NE) 的双脂双层在闭合有丝分裂过程中保持完整。在裂殖酵母粟酒裂殖酵母中，核内有丝分裂纺锤体的末端具有包膜嵌入的纺锤体极体（SPB）。随着纺锤体伸长和细胞核对称分裂，细胞核体积保持恒定，但细胞核面积迅速增加 26%。当粟酒裂殖酵母中的 Ran-GTPase 功能受损时，核分裂明显不对称，新合成的 SPB 优先与较小的核相关，表明 Ran 依赖性 SPB 缺陷会干扰对称核分裂。第二个缺陷特别影响 NE，导致纺锤体伸长时 NE 断裂。这种缺陷（但不是不对称核分裂）可以通过减慢纺锤体伸长、刺激内质网（ER）增殖或改变 ER 膜的构象来部分修复。我们认为，ER-NE 网络内脂质的重新分配对于开放和封闭有丝分裂中的有丝分裂特异性 NE 变化至关重要。
The double lipid bilayer of the nuclear envelope (NE) remains intact during closed mitosis. In the fission yeast Schizosaccharomyces pombe, the intranuclear mitotic spindle has envelope-embedded spindle pole bodies (SPB) at its ends. As the spindle elongates and the nucleus divides symmetrically, nuclear volume remains constant but nuclear area rapidly increases by 26%. When Ran-GTPase function is compromised in S. pombe, nuclear division is strikingly asymmetrical and the newly synthesized SPB is preferentially associated with the smaller nucleus, indicative of a Ran-dependent SPB defect that interferes with symmetrical nuclear division. A second defect, which specifically influences the NE, results in breakage of the NE upon spindle elongation. This defect, but not asymmetric nuclear division, is partially rescued by slowing spindle elongation, stimulating endoplasmic reticulum (ER) proliferation or changing conformation of the ER membrane. We propose that redistribution of lipid within the ER-NE network is crucial for mitosis-specific NE changes in both open and closed mitosis.