Yeast Kinesin-5 Motor Protein CIN8 Promotes Accurate Chromosome Segregation.
Yeast Kinesin-5 Motor Protein CIN8 Promotes Accurate Chromosome Segregation.
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作者：
准确的染色体分离依赖于双极染色体微管附着和染色体张力的产生。不正确的染色体附着会导致染色体错分离，从而导致基因组不稳定。着丝点是一种蛋白质复合物，位于染色体的着丝粒区域，并介导染色体与微管的相互作用。不正确的染色体附着导致检查点激活，以防止后期发作。着丝点脱离激活纺锤体组装检查点（SAC），而无张力着丝点附着依赖于SAC和张力检查点。在出芽酵母中，酿酒酵母需要驱动蛋白-5运动蛋白Cin8和Kip1来分离纺锤极体进行纺锤体组装，在没有SAC的情况下，Cin8的缺失会导致死亡。为了研究Cin8和Kip1在染色体分离中的作用，我们构建了生长素诱导脱粒（AID）突变体Cin8 -AID。在这个条件突变体中，我们首先证实了Cin8 - aid kip1∆双突变体在生长素的存在下，当Cin8被耗尽时是致命的。这些细胞在中期停止，纺锤极体和着丝点未分离。我们进一步发现，缺乏SAC或张力检查点足以消除cin8-AID突变体的细胞周期延迟，导致染色体错分离和生存能力丧失。在缺乏Cin8的细胞中，张力检查点依赖表型表明存在无张力染色体附着。我们推测，cin8突变体的纺锤极体分离失败可能增加无张力合染色体附着的机会，这取决于功能性张力检查点的生存。
Accurate chromosome segregation depends on bipolar chromosome–microtubule attachment and tension generation on chromosomes. Incorrect chromosome attachment results in chromosome missegregation, which contributes to genome instability. The kinetochore is a protein complex that localizes at the centromere region of a chromosome and mediates chromosome–microtubule interaction. Incorrect chromosome attachment leads to checkpoint activation to prevent anaphase onset. Kinetochore detachment activates the spindle assembly checkpoint (SAC), while tensionless kinetochore attachment relies on both the SAC and tension checkpoint. In budding yeast Saccharomyces cerevisiae, kinesin-5 motor proteins Cin8 and Kip1 are needed to separate spindle pole bodies for spindle assembly, and deletion of CIN8 causes lethality in the absence of SAC. To study the function of Cin8 and Kip1 in chromosome segregation, we constructed an auxin-inducible degron (AID) mutant, cin8-AID. With this conditional mutant, we first confirmed that cin8-AID kip1∆ double mutants were lethal when Cin8 is depleted in the presence of auxin. These cells arrested in metaphase with unseparated spindle pole bodies and kinetochores. We further showed that the absence of either the SAC or tension checkpoint was sufficient to abolish the cell-cycle delay in cin8-AID mutants, causing chromosome missegregation and viability loss. The tension checkpoint-dependent phenotype in cells with depleted Cin8 suggests the presence of tensionless chromosome attachment. We speculate that the failed spindle pole body separation in cin8 mutants could increase the chance of tensionless syntelic chromosome attachments, which depends on functional tension checkpoint for survival.
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DOI：
10.1111/febs.13166
发表时间：
2015-07
期刊：
The FEBS journal
影响因子：
--
作者：
Gorbsky GJ
通讯作者：
Gorbsky GJ
DOI：
10.1083/jcb.118.1.109
发表时间：
1992-07
期刊：
The Journal of cell biology
影响因子：
--
作者：
Hoyt MA;He L;Loo KK;Saunders WS
通讯作者：
Saunders WS
影响因子：
7.3
作者：
Lara-Gonzalez P;Pines J;Desai A
通讯作者：
Desai A
影响因子：
10.5
作者：
CohenFix, O;Peters, JM;Koshland, D
通讯作者：
Koshland, D
影响因子：
4.3
作者：
de Gramont, Armand;Barbour, Leslie;Cohen-Fix, Orna
通讯作者：
Cohen-Fix, Orna