酵母Pif1p螺旋酶可以从端粒DNA中去除端粒酶
Jean-Baptiste Boulé1, Leticia R Vega, Virginia A Zakian
1Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA.
Nature
|August 27, 2005
概括
Pif1p DNA 螺旋酶通过将其从染色体末端移开来限制端粒酶活性. 这种机制通过控制端粒酶的过程性和与DNA的关联来确保端粒的适当维护.
科学领域:
- 分子生物学分子生物学
- 遗传学 是一个遗传学.
- 生物化学 生物化学
背景情况:
- 端粒是真核细胞染色体末端的关键保护帽.
- 贝克酵母Pif1p DNA螺旋酶被称为端粒酶抑制剂.
- 此前,Pif1p对端粒酶的负调节的生物化学机制尚不清楚.
研究的目的:
- 为了阐明Pif1p抑制端粒酶的生物化学基础.
- 研究Pif1p影响端粒酶功能的体外和体内机制.
- 了解Pif1p是如何调节端粒维护的.
主要方法:
- 采用纯化的Pif1p和端粒酶进行了体外生化分析.
- 对端粒酶过程性和与端粒DNA脱离的分析.
- 在体内研究涉及Pif1p在酵母中的过度表达和耗尽.
- 在体内评估端粒酶子单元 (Est1p) 的端粒关联.
主要成果:
- 在实验室中,Pif1p降低了telomerase在telomeric DNA上的过程性.
- Pif1p从DNA末端积极释放活性端粒酶.
- 在体内,过度表达Pif1p会降低端粒酶与端粒的关联.
- 缺少Pif1p会增加与端粒结合的Est1p水平,这表明端粒酶活性增强.
结论:
- Pif1p 作为一种 DNA 螺旋酶,可以从端粒中取代端粒酶.
- 这种移位活动限制了telomerase的作用,在体外和体内.
- Pif1p的螺旋酶活性是端粒长度维持的关键调节者.
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