A role for KEM1 at the START of the cell cycle in Saccharomyces cerevisiae.
A role for KEM1 at the START of the cell cycle in Saccharomyces cerevisiae.
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KEM1 在酿酒酵母细胞周期起始阶段的作用。
DOI：
10.1007/s00294-005-0030-5
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发表时间：
2005
期刊：
影响因子：
2.5
通讯作者：
Polymenis,Michael
中科院分区：
文献类型：
--
作者：
Pathak,Ritu;Bogomolnaya,LydiaM;Guo,Jinbai;Polymenis,Michael
KEM 1是一个在真核生物中保守的酿酒酵母基因，其缺失导致多效性表型。在大多数情况下，这些表型被认为是由Kem 1 p在RNA周转中的作用引起的，因为Kem 1 p是一种主要的5′-3′细胞质外切核酸酶。例如，Kem 1 p的核酸外切酶依赖性作用通过降解有丝分裂细胞周期蛋白CLB 2的mRNA参与有丝分裂的退出。在这里，我们描述了一个KEM 1 truncation，KEM 11 -975，加速G1到S过渡和启动DNA复制时，过度表达的鉴定。有趣的是，尽管这种截短的Kem 1 p缺乏核酸外切酶活性，但它可以有效地补充另一种受KEM 1缺失影响的功能，即微管依赖性核迁移。两者合计，我们在这里报告的结果表明，Kem 1 p可能有一个以前未被认识到的作用，在G1到S的过渡，但不是通过其核酸外切酶活性。我们的研究结果也支持Kem 1 p是一种多功能蛋白质，具有独特和可分离的作用。
KEM1is aSaccharomyces cerevisiaegene, conserved in all eukaryotes, whose deletion leads to pleiotropic phenotypes. For the most part, these phenotypes are thought to arise from Kem1p’s role in RNA turnover, because Kem1p is a major 5′–3′ cytoplasmic exonuclease. For example, the exonuclease-dependent role of Kem1p is involved in the exit from mitosis, by degrading the mRNA of the mitotic cyclinCLB2. Here, we describe the identification of aKEM1truncation,KEM11-975, that accelerated the G1 to S transition and initiation of DNA replication when over-expressed. Interestingly, although this truncated Kem1p lacked exonuclease activity, it could efficiently complement another function affected by the loss ofKEM1, microtubule-dependent nuclear migration. Taken together, the results we report here suggest that Kem1p might have a previously unrecognized role at the G1 to S transition, but not through its exonuclease activity. Our findings also support the notion that Kem1p is a multifunctional protein with distinct and separable roles.