The functional role of SUMO E3 ligase Mms21p in the maintenance of subtelomeric silencing in budding yeast.
The functional role of SUMO E3 ligase Mms21p in the maintenance of subtelomeric silencing in budding yeast.
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DOI：
10.1016/j.bbrc.2013.07.096
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发表时间：
2013-09
影响因子：
3.1
通讯作者：
Yakun Wan;Xiao Zuo;Y. Zhuo;M. Zhu;Samuel A. Danziger;Zikai Zhou
中科院分区：
文献类型：
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作者：
Yakun Wan;Xiao Zuo;Y. Zhuo;M. Zhu;Samuel A. Danziger;Zikai Zhou
在酿酒酵母中，亚端粒沉默参与沉默信息调节因子（SIR）蛋白向常染色质的传播。许多机制参与拮抗sir依赖性沉默染色质向邻近常染色质的局部扩散。在这里，我们确定了一个新的作用sumoylation E3连接酶Mms21在维持亚端粒沉默。我们发现Mms21的E3连接酶活性的破坏导致亚端粒沉默的去阻遏。Mms21的E3连接酶结构域的缺失导致Sir2p、Sir3p和Sir4在亚端粒染色质的结合减少和端粒远端常染色质区域的H3K4三甲基化增加，这与两个亚端粒报告基因的基因表达增加相关。此外，amms 21 Δ sl突变体与htz 1 Δ缺失联合导致严重的生长缺陷，并显示出htz 1与端粒近端区域的增强关联。两者合计，我们的研究结果表明Mms21 p的重要作用，它有助于亚端粒沉默过程中形成的异染色质边界。
InSaccharomyces cerevisiae, subtelomeric silencing is involved in the propagation of Silent Information Regulator (SIR) proteins toward euchromatin. Numerous mechanisms are involved in antagonizing the local spread of Sir-dependent silent chromatin into neighboring euchromatin. Here, we identified a novel role for sumoylation E3 ligase Mms21 in the maintenance of subtelomeric silencing. We found that disruption of E3 ligase activity of Mms21 results in the de-repression of subtelomeric silencing. Deletion of E3 ligase domain of Mms21 led to decreased binding of Sir2p, Sir3p and Sir4 at subtelomeric chromatins and increased H3K4 tri-methylation at telomere-distal euchromatin regions, correlating with increased gene expression in two subtelomeric reporter genes. In addition, amms21Δslmutant caused a severe growth defect in combination withhtz1Δ deletion and showed an enhanced association of Htz1 with telomere proximal regions. Taken together, our findings suggest an important role of Mms21p; it contributes to subtelomeric silencing during the formation of a heterochromatin boundary.