真核生物的端粒（Telomere）對(duì)于保證染色體正常復(fù)制以及維持基因組的穩(wěn)定性有重要作用,，也是研究基因組中異染色質(zhì)（Heterochromatin）結(jié)構(gòu)的重要模型。
9月19日,，Nucleic Acids Research在線發(fā)表了中科院上海生命科學(xué)研究院生化與細(xì)胞所周金秋研究組揭示酵母轉(zhuǎn)錄中介復(fù)合物調(diào)控端粒機(jī)制的最新研究結(jié)果,。研究生彭晶以釀酒酵母為模式生物，闡述了轉(zhuǎn)錄中介復(fù)合物（Mediator complex）調(diào)控端粒異染色質(zhì)結(jié)構(gòu)的分子機(jī)制,。轉(zhuǎn)錄中介復(fù)合物的尾部模塊通過幫助異染色質(zhì)核心組分Sir蛋白在端粒上的結(jié)合和擴(kuò)散參與端粒異染色質(zhì)的維持,，從而保證亞端粒區(qū)域基因的沉默。轉(zhuǎn)錄中介復(fù)合物直接結(jié)合在端粒上,，可能作為端粒染色質(zhì)的組分之一發(fā)揮功能,。此外，該復(fù)合物還參與了端粒長(zhǎng)度的調(diào)控,。
這一工作揭示了轉(zhuǎn)錄中介復(fù)合物這一經(jīng)典的轉(zhuǎn)錄調(diào)控因子在端粒調(diào)控中的特殊功能,。
該研究得到了科技部和國家自然科學(xué)基金委的經(jīng)費(fèi)資助。（生物谷 Bioon.com）
doi:10.1093/nar/gkr757
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The tail-module of yeast Mediator complex is required for telomere heterochromatin maintenance
Jing Peng and Jin-Qiu Zhou
Eukaryotic chromosome ends have a DNA–protein complex structure termed telomere. Integrity of telomeres is essential for cell proliferation. Genome-wide screenings for telomere length maintenance genes identified several components of the transcriptional regulator, the Mediator complex. Our work provides evidence that Mediator is involved in telomere length regulation and telomere heterochromatin maintenance. Tail module of Mediator is required for telomere silencing by promoting or stabilizing Sir protein binding and spreading on telomeres. Mediator binds on telomere and may be a component of telomeric chromatin. Our study reveals a specific role of Mediator complex at the heterochromatic telomere and this function is specific to telomeres as it has no effect on the HMR locus.
