行动中的转录启动的结构可视化
Xizi Chen1,2, Weida Liu1, Qianmin Wang1
1Fudan University Shanghai Cancer Center, Institutes of Biomedical Sciences, New Cornerstone Science Laboratory, State Key Laboratory of Genetic Engineering, Department of Biochemistry and Biophysics, School of Life Sciences, Shanghai Key Laboratory of Radiation Oncology, and Shanghai Key Laboratory of Medical Epigenetics, Shanghai Medical College of Fudan University, Shanghai 200032, China.
概括
这项研究揭示了RNA聚合酶II的转录启动的动态过程. 它表明一般转录因子 (GTF) 对于早期RNA合成至关重要,但必须脱离促进体逃逸.
科学领域:
- 分子生物学
- 结构生物学
- 生物化学
背景情况:
- 转录是一个基本的生物过程.
- 转录启动的精确机制,特别是从启动到延长的过渡,仍然不完全理解.
- RNA聚合酶II转录蛋白质编码基因,其调节对基因表达至关重要.
研究的目的:
- 阐明转录启动过程中的动态结构变化.
- 了解一般转录因子 (GTF) 和转录泡在从启动到延长的过渡中的作用.
- 开发一种通过RNA聚合酶II启动新转录的工作模型.
主要方法:
- 在新生RNA合成 (2至17核酸) 的不同阶段确定RNA聚合酶II转录复合体 (TC2至TC17) 的结构.
- 使用冷电子显微镜或X射线晶体学来捕获动态中间体的静态快照.
- 整合结构数据以生成时间解析的转录启动"电影".
主要成果:
- 观察到,随着新生RNA的生长,一般转录因子 (GTF) 仍然与促进子结合在一起.
- 在初始RNA合成过程中记录了转录泡的扩张.
- 已确定核三酸盐 (NTP) 驱动的RNA-DNA转位和模板链积累是从最初转录复合体 (ITC) 过渡到早期延长复合体 (EEC) 的潜在驱动因素.
结论:
- 最初转录复合体 (ITC) 需要GTF和扩展的转录泡进行初始RNA合成.
- 早期延长复合体 (EEC) 需要GTF与促进体分离,并且转录泡崩使促进体逃逸.
- 这项研究提供了转录启动的动态模型,突出了关键的转换和因子要求.
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