在由LTR逆转移子暂停的复制分叉时,CENP-B保持了基因组完整性
Mikel Zaratiegui1, Matthew W Vaughn, Danielle V Irvine
1Cold Spring Harbor Laboratory, 1 Bungtown Road, Cold Spring Harbor, New York 11724, USA.
Nature
|December 15, 2010
概括
中心结合蛋白B (CENP-B) 通过LTR逆转移子促进DNA复制叉的进展. 由于复制分叉阻塞,CENP-B的损失导致基因组不稳定,突出显示了它在维持基因组稳定中的作用.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 表观遗传学 在表观遗传学中,表观遗传学是指表观遗传学.
背景情况:
- 中心结合蛋白B (CENP-B) 是一种与异色素和中心重复相关的保存DNA结合因子.
- 在裂变酵母中CENP-B同类物通过基因素脱乙酶沉默LTR逆转基因.
- 已经注意到CENP-B在DNA复制中的不明原因的作用.
研究的目的:
- 阐明CENP-B在DNA复制中的分子功能.
- 研究CENP-B在通过LTR逆转移体的复制分叉进展中的作用.
- 了解CENP-B突变体中基因组不稳定的机制.
主要方法:
- 使用裂变酵母模型分析DNA复制中的CENP-B功能.
- 研究复制分叉动态和阻塞在LTR序列.
- 评估CENP-B突变体中的基因组不稳定性和DNA重组.
- 研究CENP-B,LTRs和DNA结合因子Sap1.1之间的相互作用.
主要成果:
- 通过LTR序列,CENP-B积极促进复制分叉的进展.
- 缺乏CENP-B的突变者由于复制分叉阻塞而增加了基因组不稳定性.
- 复制分叉阻塞取决于由LTRs招募的开关激活蛋白1 (Sap1).
- 失去Sap1介导的屏障活性会导致不受阻碍的分叉进展,但会导致有害的逆转移素重组.
结论:
- CENP-B可以抵消LTR介导的复制分叉阻塞,促进分叉稳定性.
- 逆转移子通过在复制叉块附近招募Sap1来影响复制极性.
- 这些发现可能解释了LTRs在脆弱部位的作用以及CENP-B与周围中心的异性染色素的关联.
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