MIF2 is required for mitotic spindle integrity during anaphase spindle elongation in Saccharomyces cerevisiae.
MIF2 is required for mitotic spindle integrity during anaphase spindle elongation in Saccharomyces cerevisiae.
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DOI：
10.1083/jcb.123.2.387
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发表时间：
1993-10
期刊：
影响因子：
--
通讯作者：
Hartwell LH
中科院分区：
文献类型：
--
作者：
Brown MT;Goetsch L;Hartwell LH
通过抑制或产生MIF2基因产物的缺陷来检查酿酒酵母细胞周期中必需MIF2基因的功能。当MIF2过表达时，染色体在有丝分裂过程中错误分离，细胞在细胞周期的G2和M期积累。通过体外诱变分离的温度敏感突变体在限制性温度下生长时延迟细胞周期进程，积累为已完成DNA复制但未分离染色体的大出芽细胞，并且在通过有丝分裂时失去活力。突变细胞还表现出有丝分裂染色体丢失水平增加，对微管不稳定药物MBC的超敏感性，以及形态异常的纺锤体。MIF2突变体纺锤体在发育后期纺锤体伸长前立即停止发育，然后经常分裂成两个不连续的短半纺锤体，纺锤体极体取向错误。这些发现表明，MIF2是所需的后期纺锤体伸长的纺锤体的结构完整性。推导的Mif2蛋白质序列没有广泛的同源性与以前确定的蛋白质，但确实包含一个短区域的同源性的基序参与结合AT丰富的DNA由果蝇D1和哺乳动物HMGI染色体蛋白。
The function of the essential MIF2 gene in the Saccharomyces cerevisiae cell cycle was examined by overepressing or creating a deficit of MIF2 gene product. When MIF2 was overexpressed, chromosomes missegregated during mitosis and cells accumulated in the G2 and M phases of the cell cycle. Temperature sensitive mutants isolated by in vitro mutagenesis delayed cell cycle progression when grown at the restrictive temperature, accumulated as large budded cells that had completed DNA replication but not chromosome segregation, and lost viability as they passed through mitosis. Mutant cells also showed increased levels of mitotic chromosome loss, supersensitivity to the microtubule destabilizing drug MBC, and morphologically aberrant spindles. mif2 mutant spindles arrested development immediately before anaphase spindle elongation, and then frequently broke apart into two disconnected short half spindles with misoriented spindle pole bodies. These findings indicate that MIF2 is required for structural integrity of the spindle during anaphase spindle elongation. The deduced Mif2 protein sequence shared no extensive homologies with previously identified proteins but did contain a short region of homology to a motif involved in binding AT rich DNA by the Drosophila D1 and mammalian HMGI chromosomal proteins.