Mcm10 is required for the maintenance of transcriptional silencing in Saccharomyces cerevisiae
Mcm10 is required for the maintenance of transcriptional silencing in Saccharomyces cerevisiae
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DOI：
10.1534/genetics.105.042333
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发表时间：
2005-10-01
期刊：
影响因子：
3.3
通讯作者：
Tye, BK
中科院分区：
文献类型：
--
作者：
Liachko, I;Tye, BK
Mcm10是参与DNA复制起始和延伸的重要蛋白。在这项研究中，我们证明了Mcm10在维持芽殖酵母端粒和HM位点的异色沉默中的作用。两个mcm10突变体显著减少了URA3和ADE2报告基因的沉默，这些基因整合在这些沉默位点上。当暴露于α -因子时，mcm10突变细胞表现出与沉默维持缺陷相关的“shmoo-cluster”表型。此外，当mcm10突变体与沉默染色质建立缺陷结合时，mcm10突变体在HML沉默中表现出协同缺陷。与直接沉默功能一致，Mcm10p显示出与Sir2p和Sir3p的双杂交相互作用，该相互作用被mcm10-1突变和依赖于c端108氨基酸的油破坏。将GBD-MCM10绑在有缺陷的HMR-E消音器上不足以恢复沉默。此外，MCM10突变抑制GBD-SIR3在连接有缺陷的HAM-E时恢复沉默的能力。MCM2中的抑制因子仿生物抑制MCM10 -1的温度敏感性，但未能克服MCM10 -1的沉默缺陷，这表明MCM10在转录沉默中的作用可能与其在DNA复制中的基本功能分开。
Mcm10 is an essential protein that participates in both the initiation and the elongation of DNA replication. In this study we demonstrate a role for Mcm10 in the maintenance of heterochromatic silencing at telomeres and HM loci of budding yeast. Two mcm10 mutants drastically reduce silencing of both URA3 and ADE2 reporter genes integrated into these silent loci. When exposed to alpha-factor, mcm10 mutant cells display a "shmoo-cluster" phenotype associated with a defect in the maintenance of silencing. In addition, when combined with a defect in the establishment of silent chromatin, mcm10 mutants demonstrate a synergistic defect in HML silencing. Consistent with a direct silencing function, Mcm10p shows a two-hybrid interaction with Sir2p and Sir3p that is destroyed by the mcm10-1 mutation and dependent oil the C-terminal 108 amino acids. Tethering GBD-MCM10 to a defective HMR-E silencer is not sufficient to restore silencing. Furthermore, mutations in MCM10 inhibit the ability of GBD-SIR3 to restore silencing when tethered to a defective HAM-E. Suppressor imitations ill MCM2, which Suppress the temperature sensitivity of mcm10-1, fail to overcome the mcm10-1 silencing defect, suggesting that MCM10's role in transcriptional silencing may be separate from its essential functions in DNA replication.