Functional roles for evolutionarily conserved Spt4p at centromeres and heterochromatin in Saccharomyces cerevisiae
Functional roles for evolutionarily conserved Spt4p at centromeres and heterochromatin in Saccharomyces cerevisiae
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DOI：
10.1038/sj.emboj.7600161
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发表时间：
2004-04-21
期刊：
影响因子：
11.4
通讯作者：
Basrai, MA
中科院分区：
文献类型：
--
作者：
Crotti, LB;Basrai, MA
着丝粒（着丝粒DNA和相关蛋白质）介导染色体附着到有丝分裂纺锤体上，并且是忠实的染色体传递所必需的。我们建立了进化上保守的酿酒酵母SPT 4，以前确定在染色体传递保真度（ctf）的缺陷的遗传筛选，编码一个新的结构组件的特化染色质在动粒和异染色质基因座，动粒功能和基因沉默的作用。使用染色质免疫沉淀试验（ChIP），我们确定，着丝粒蛋白Ndc 10 p，Cac 1 p，和Hir 1 p的协会Spt 4p着丝粒（CEN）位点所需的。功能Spt 4p的缺失导致CEN DNA的染色质结构改变和哺乳动物CENP-A同源物Cse 4p到非着丝粒位点的错误定位。Spt 4p以Sir 3 p依赖的方式与端粒（TEL）和HMRa位点相关联，并且是转录基因沉默所需的。我们发现，一个人类同源的SPT 4（HsSPT 4）补充Scspt 4沉默缺陷和协会与ScCEN DNA在Ndc 10 p依赖的方式。我们的研究结果强调了酵母和人类基因组稳定性所需途径的进化保守性。
The kinetochore (centromeric DNA and associated proteins) mediates the attachment of chromosomes to the mitotic spindle apparatus and is required for faithful chromosome transmission. We established that evolutionarily conserved Saccharomyces cerevisiae SPT4, previously identified in genetic screens for defects in chromosome transmission fidelity (ctf), encodes a new structural component of specialized chromatin at kinetochores and heterochromatic loci, with roles in kinetochore function and gene silencing. Using chromatin immunoprecipitation assays (ChIP), we determined that kinetochore proteins Ndc10p, Cac1p, and Hir1p are required for the association of Spt4p to centromeric (CEN) loci. Absence of functional Spt4p leads to altered chromatin structure at the CEN DNA and mislocalization of the mammalian CENP-A homolog Cse4p to noncentromeric loci. Spt4p associates with telomeres (TEL) and HMRa loci in a Sir3p-dependent manner and is required for transcriptional gene silencing. We show that a human homolog of SPT4 (HsSPT4) complements Scspt4-silencing defects and associates with ScCEN DNA in an Ndc10p-dependent manner. Our results highlight the evolutionary conservation of pathways required for genome stability in yeast and humans.