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在eIF5和eIF2β中的翻译启动忠实性缺陷突变对识别UUG启动符号的序列上下文具有明显的敏感性
Anup Kumar Ram1,2,3, Tanaya Kole1,2, Pankaj V Alone4,5
1School of Biological Sciences, National Institute of Science Education and Research (NISER) Bhubaneswar, P.O. Jatni, Khurda, 752050, India.
Biochemical genetics
|December 29, 2025
概括
突变的酵母蛋白 (eIF5 ((G31R) 和eIF2β ((S264Y)) 可以在UUG编码子上启动翻译. 序列上下文,特别是 -3 和 -1 位置的 purin,影响了这种近同源起始编码子选择.
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:
- 在Saccharomyces cerevisiae中,翻译通常始于AUG编码子,具有首选的序列背景.
- 细胞启动因子5 (eIF5) 或eIF2β的突变可以导致非正规UUG编码子的翻译启动,称为"启动编码子抑制者" (Sui−) 的表型.
研究的目的:
- 为了研究围绕UUG起始编码子的核酸序列在Sui−突变体的选择中的作用.
- 为了确定eIF5 ((G31R) 和eIF2β ((S264Y) 突变的独特序列偏好,以启动在UUG编码子上的翻译.
主要方法:
- 构建HIS4-LacZ记者基因,以UUG作为起始编码子,以及在位置 -3, -2,和 -1.1处的多种核酸.
- 记者结构的转化为携带eIF5 (G31R) 或eIF2β (S264Y) 突变的酵母菌株.
- 测量β-galactosidase活性以量化记者基因表达和评估UUG启动密码子选择.
主要成果:
- 与胺素 (U或C) 相比,在 -3 位置具有纯素 (A或G) 的报告者构造显示出明显更高的活性.
- purin 在 -1 位置也受到青,特别是在 AA 背景下在 -3 和 -2 位置,以使突变者能够高效地选择 UUG 启动子.
- 在eIF5 (((G31R)) 和eIF2β ((S264Y)) Sui−突变之间观察到明显的序列上下文偏好.
结论:
- 由Sui-突变体选择近同类的UUG起始编码子受到周围核酸序列环境的强烈影响.
- 在 -3 和 -1 位置的特定核酸偏好调节了这些突变物中翻译启动的忠实性.
- 这些发现强调了序列上下文在翻译启动过程中近同源起始密码子识别中的关键作用.
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