CHARACTERIZATION OF 4 B-TYPE CYCLIN GENES OF THE BUDDING YEAST SACCHAROMYCES-CEREVISIAE
CHARACTERIZATION OF 4 B-TYPE CYCLIN GENES OF THE BUDDING YEAST SACCHAROMYCES-CEREVISIAE
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DOI：
10.1091/mbc.3.7.805
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发表时间：
1992-07-01
影响因子：
3.3
通讯作者：
FUTCHER, B
中科院分区：
文献类型：
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作者：
FITCH, I;DAHMANN, C;FUTCHER, B
先前描述的CLB1和CLB2基因编码一对密切相关的b型细胞周期蛋白。在这里，我们展示了另一对相关的b型周期蛋白基因的序列，我们称之为CLB3和CLB4。尽管CLB1和CLB2 mrna在核分裂时丰度上升，但CLB3和CLB4的开启时间较早，在S期早期上升，在核分裂结束时下降。当构建所有可能的单和多缺失突变体时，一些多突变体是致死的，而所有的单突变体都是活的。所有致死组合都包括clb2缺失，而clb1 clb3 clb4三重突变体是活的，表明clb2在其中起关键作用。不存活的多clb突变体似乎在有丝分裂中有缺陷。条件clb突变体被捕获为具有G2 DNA含量的大出芽细胞，但没有任何有丝分裂纺锤体。电镜观察显示，主轴极体有重复但未分离，未形成主轴。这表明Clb/Cdc28激酶可能在纺锤体形成中起相对直接的作用。两组clb在纺锤体形成和伸长方面可能有不同的作用。
The previously described CLB1 and CLB2 genes encode a closely related pair of B-type cyclins. Here we present the sequences of another related pair of B-type cyclin genes, which we term CLB3 and CLB4. Although CLB1 and CLB2 mRNAs rise in abundance at the time of nuclear division, CLB3 and CLB4 are turned on earlier, rising early in S phase and declining near the end of nuclear division. When all possible single and multiple deletion mutants were constructed, some multiple mutations were lethal, whereas all single mutants were viable. All lethal combinations included the clb2 deletion, whereas the clb1 clb3 clb4 triple mutant was viable, suggesting a key role for CLB2. The inviable multiple clb mutants appeared to have a defect in mitosis. Conditional clb mutants arrested as large budded cells with a G2 DNA content but without any mitotic spindle. Electron microscopy showed that the spindle pole bodies had duplicated but not separated, and no spindle had formed. This suggests that the Clb/Cdc28 kinase may have a relatively direct role in spindle formation. The two groups of Clbs may have distinct roles in spindle formation and elongation.