The mitotic checkpoint gene BubR1 has two distinct functions in mitosis
The mitotic checkpoint gene BubR1 has two distinct functions in mitosis
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DOI：
10.1016/j.yexcr.2005.03.036
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发表时间：
2005-08-01
影响因子：
3.7
通讯作者：
Goorha, R
中科院分区：
文献类型：
--
作者：
Harris, L;Davenport, J;Goorha, R
BubR1是酵母纺锤体检查点蛋白Bub1的两个可能的脊椎动物同源物之一。我们使用缺失突变和点突变来阐明BubR1在有丝分裂中的功能。含有Bub3结合GLEBS基序的BubR1的39个氨基酸片段(残基382-420)的表达扰乱了诺可达唑激活的HeLa细胞的纺锤体检查点。相反，我们在一个由1-477个残基组成的截断突变体中观察到了正常的检查点功能，尽管缺乏C-末端的BubR1激活域。在没有诺考唑的情况下，477个氨基酸片段的表达通过有丝分裂的前中期减慢了进程，导致有丝分裂细胞的积累。这种积聚也出现在一个激酶死亡突变体中。有丝分裂的延长既需要动粒结合，也需要完整的、功能正常的纺锤体检查点。除了N端在检验点中的作用外，通过构建有丝分裂缺陷的BubR1结构域来延长有丝分裂也表明了BubR1C-末端的激酶结构域在染色体运动中的重要作用。(C)2005 Elsevier Inc.保留所有权利。
BubR1 is one of two putative vertebrate homologs of the yeast spindle checkpoint protein Bub1. We have used deletion and point mutants to elucidate the functions of BubR1 in mitosis. The nocodazole-activated spindle checkpoint of HeLa cells was disrupted by expression of a 39 amino acid fragment (residues 382-420) of BubR1 containing the Bub3-binding GLEBS motif. In contrast, we observed normal checkpoint function in a truncation mutant comprising residues 1-477, despite the lack of the C-terminal BubR1 kinase domain. In the absence of nocodazole, expression of the 477 amino acid fragment slowed progress through prometaphase of mitosis, causing accumulation of mitotic cells. This accumulation was also seen in a kinase dead mutant. The prolongation of mitosis required both kinetochore binding and an intact, functional spindle checkpoint. The prolongation of mitosis by kinase deficient BubR1 constructs indicates a crucial role for the BubR1 C-terminal kinase domain in chromosome movement, in addition to the role of the N-terminus in the checkpoint. (c) 2005 Elsevier Inc. All rights reserved.