Cell cycle requirements in assembling silent chromatin in Saccharomyces cerevisiae
Cell cycle requirements in assembling silent chromatin in Saccharomyces cerevisiae
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DOI：
10.1128/mcb.26.3.852-862.2006
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发表时间：
2006-02-01
影响因子：
5.3
通讯作者：
Rine, J
中科院分区：
文献类型：
--
作者：
Kirchmaier, AL;Rine, J
在酿酒酵母中沉默交配型基因座HMR处沉默的建立需要酵母通过细胞周期的S期，但既不需要在注定要沉默的基因座处启动DNA复制，也不需要复制叉通过该基因座。我们测试了这种S期要求是否反映了细胞周期内允许将Sir蛋白募集到HMR的窗口。沉默所必需的S期限制事件发生在Sir蛋白向HMR募集后。此外，在早期S期停滞的细胞在HMR处形成沉默的染色质，只要HMR在非复制模板上。复制模板需要后续步骤进行沉默。这些结果提供了沉默染色质形成的离散步骤的时间分辨率，并表明一个以上的细胞周期调节事件可能是必要的沉默的建立。
The establishment of silencing at the silent mating-type locus, HMR, in Saccharomyces cerevisiae requires that yeast pass through S phase of the cell cycle, yet requires neither the initiation of DNA replication at the locus destined to become silenced nor the passage of a replication fork through that locus. We tested whether this S-phase requirement reflects a window within the cell cycle permissive for recruitment of Sir proteins to HMR. The S-phase-restricted event necessary for silencing occurred after recruitment of Sir proteins to HMR. Moreover, cells arrested in early S phase formed silent chromatin at HMR, provided HMR was on a nonreplicating template. Replicating templates required a later step for silencing. These results provide temporal resolution of discrete steps in the formation of silent chromatin and suggest that more than one cell cycle-regulated event may be necessary for the establishment of silencing.