In vivo analysis of chromosome condensation in Saccharomyces cerevisiae.
In vivo analysis of chromosome condensation in Saccharomyces cerevisiae.
复制标题
酿酒酵母染色体凝缩的体内分析。
DOI：
10.1091/mbc.e06-05-0454
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发表时间：
2007
影响因子：
3.3
通讯作者：
Clarke,DuncanJ
中科院分区：
文献类型：
--
作者：
Vas,AmitCJ;Andrews,CatherineA;KirklandMatesky,Kathryn;Clarke,DuncanJ
虽然酵母中的染色体浓缩已经被广泛研究，但这一过程在体内的可视化还没有实现。使用Lac操作序列整合在染色体IV和Lac阻遏物-GFP融合蛋白的右臂上的两个位点，我们能够可视化在G2/M期期间该染色体臂的线性浓缩。如先前在固定细胞中所确定的，酵母中的缩合需要缩合素复合物。固定细胞后未见，我们发现拓扑异构酶II是线性缩合所需的。进一步分析扰动的有丝分裂意外地发现，凝聚是一个短暂的状态，发生在芽殖酵母后期之前。通过激活纺锤体组装检查点来阻断后期进程导致依赖于Mad 2的凝聚损失，随后是姐妹染色单体之间的凝聚力延迟损失。细胞从纺锤体检查点停滞中释放导致后期开始之前的再浓缩。在后期前停滞的细胞中的凝结损失被极光B激酶Ipl 1的过度产生所废除，而inipl 1 - 321突变体细胞凝结在后期/末期过早地丧失。因此，染色体凝聚的体内分析揭示了高级染色质结构和细胞周期控制之间的未知关系。
Although chromosome condensation in the yeastSaccharomyces cerevisiaehas been widely studied, visualization of this process in vivo has not been achieved. Using Lac operator sequences integrated at two loci on the right arm of chromosome IV and a Lac repressor-GFP fusion protein, we were able to visualize linear condensation of this chromosome arm during G2/M phase. As previously determined in fixed cells, condensation in yeast required the condensin complex. Not seen after fixation of cells, we found that topoisomerase II is required for linear condensation. Further analysis of perturbed mitoses unexpectedly revealed that condensation is a transient state that occurs before anaphase in budding yeast. Blocking anaphase progression by activation of the spindle assembly checkpoint caused a loss of condensation that was dependent on Mad2, followed by a delayed loss of cohesion between sister chromatids. Release of cells from spindle checkpoint arrest resulted in recondensation before anaphase onset. The loss of condensation in preanaphase-arrested cells was abrogated by overproduction of the aurora B kinase, Ipl1, whereas inipl1-321mutant cells condensation was prematurely lost in anaphase/telophase. In vivo analysis of chromosome condensation has therefore revealed unsuspected relationships between higher order chromatin structure and cell cycle control.