转录调节器Rap1在Saccharomyces cerevisiae中的基因沉默和激活中的上下文依赖功能
Eliana R Bondra1, Jasper Rine1
1Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720.
概括
抑制器激活蛋白 (Rap1) 通过与Sir蛋白相互作用,保持酵母中的沉默色素,挑战了以前的基因沉默模型. 拉普1 拉普1 拉普1
科学领域:
- * 分子生物学 * 分子生物学
- * 遗传学 遗传学是一门学科
- * 表观遗传学 是一种表观遗传学.
背景情况:
- 在*Saccharomyces cerevisiae*中,异性染色体的形成涉及诸如抑制活性蛋白 (Rap1) 和Sir蛋白等DNA结合因子.
- * 酵母中的Sir蛋白质对基因沉默的确切机制尚不清楚.
- * 之前的模型表明,Sir蛋白质不分青红白地阻止转录机器的访问.
研究的目的:
- *阐明酵母中Sir蛋白对基因沉默的机制.
- * 调查Rap1在维持Sir沉默染色质中的作用.
- * 了解Rap1的功能是如何受到当地的染色体环境的影响.
主要方法:
- *高分辨率染色体免疫沉 (ChIP) 用于分析蛋白质结合.
- * 敏感测定用于监测丧失沉默事件.
- *分析了Rap1结合和转录机械在沉默和表达的染色体状态中的访问.
主要成果:
- * Rap1将其识别序列结合到沉默的染色质中,由Sir蛋白增强结合.
- *转录机器无法在沉默状态下访问*HML*α促销器,从而驳斥了不分青红白的硬质障碍.
- * 与促进体结合的Rap1对于通过Sir复杂相互作用保持沉默色素至关重要.
- * Rap1在表达状态下激活*HML*α,并促进转录启动到延长.
- * Rap1的双重功能是由当地的染色体环境调解的,而不仅仅是结合位点的可用性.
结论:
- * 长期存在的Sir蛋白质不分青红白闭塞的模型被证实为错误.
- * 与促进体结合的Rap1在维持酵母异色素蛋白中起着至关重要的作用.
- *表观遗传背景决定了像Rap1这样的转录因子的功能.
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