NUP1 MUTANTS EXHIBIT PLEIOTROPIC DEFECTS IN NUCLEAR-PORE COMPLEX FUNCTION
NUP1 MUTANTS EXHIBIT PLEIOTROPIC DEFECTS IN NUCLEAR-PORE COMPLEX FUNCTION
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DOI：
10.1083/jcb.127.2.319
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发表时间：
1994-10-01
影响因子：
7.8
通讯作者：
DAVIS, LI
中科院分区：
文献类型：
--
作者：
BOGERD, AM;HOFFMAN, JA;DAVIS, LI
酿酒酵母的 NUP1 基因编码从酵母到脊椎动物都保守的核孔复合蛋白（核孔蛋白）家族的一个成员。我们使用突变分析来研究 Nup1p 的功能。氨基或羧基末端结构域的缺失会产生致死表型，但任一末端的部分截短都会不同程度地影响生长。氨基末端截短会导致突变蛋白的错误定位和降解，表明该结构域是将 Nup1p 靶向核孔复合物所必需的。羧基末端突变体是稳定的，但不具有野生型功能，并赋予温度敏感表型。在不允许的温度下，核蛋白的输入和 Poly(A) RNA 的输出都有缺陷。此外，nup1 突变细胞在所有温度下都会变成多核，这种表型表明核迁移存在缺陷。微管蛋白染色显示，尽管存在明显正常的细胞质微管将一个纺锤体极体连接到芽尖，但有丝分裂纺锤体似乎相对于芽随机定向。电镜分析表明，核膜形成延伸至细胞质的长突起，这些突起似乎已与大部分细胞核分离。我们的结果表明，可能需要 Nup1p 来保持核膜和底层核支架之间的结构完整性，并且需要这种连接来允许细胞核响应细胞骨架力而重新定向。
The NUP1 gene of Saccharomyces cerevisiae encodes one member of a family of nuclear pore complex proteins (nucleoporins) conserved from yeast to vertebrates. We have used mutational analysis to investigate the function of Nup1p. Deletion of either the amino- or carboxy-terminal domain confers a lethal phenotype, but partial truncations at either end affect growth to varying extents. Amino-terminal truncation causes mislocalization and degradation of the mutant protein, suggesting that this domain is required for targeting Nup1p to the nuclear pore complex. Carboxy-terminal mutants are stable but do not have wild-type function, and confer a temperature sensitive phenotype. Both import of nuclear proteins and export of poly(A) RNA are defective at the nonpermissive temperature. In addition, nup1 mutant cells become multinucleate at all temperatures, a phenotype suggestive of a defect in nuclear migration. Tubulin staining revealed that the mitotic spindle appears to be oriented randomly with respect to the bud, in spite of the presence of apparently normal cytoplasmic microtubules connecting one spindle pole body to the bud tip. EM analysis showed that the nuclear envelope forms long projections extending into the cytoplasm, which appear to have detached from the bulk of the nucleus. Our results suggest that Nup1p may be required to retain the structural integrity between the nuclear envelope and an underlying nuclear scaffold, and that this connection is required to allow reorientation of the nucleus in response to cytoskeletal forces.