40S核糖体子单元通过一维扩散扫描mRNA以寻找起始编码子.
Hironao Wakabayashi1, Mingyi Zhu1, Elizabeth J Grayhack1
1Department of Biochemistry & Biophysics at the School of Medicine and Dentistry & Center for RNA Biology, University of Rochester, Rochester, NY, USA.
bioRxiv : the preprint server for biology
|January 13, 2025
概括
酵母中的40S核糖体亚单元的mRNA扫描主要是由一维扩散驱动的,而不是螺旋酶活动. 非结构化的5'非翻译区域 (UTR) 的影响最小,而二次结构显著抑制翻译.
科学领域:
- 分子生物学分子生物学
- 遗传学 遗传学 是一个
- 生物化学 生物化学
背景情况:
- 细胞翻译启动涉及40S核糖体子单元扫描mRNA的5'未翻译区域 (UTR),以找到开始的编码子.
- 控制mRNA扫描的精确分子机制尚不完全理解.
研究的目的:
- 在真核细胞翻译启动过程中,研究40S核糖体子单元对mRNA扫描的分子机制.
- 确定RNA螺旋酶和其他启动因子在mRNA扫描中的作用及其对蛋白质合成的影响.
主要方法:
- 在Saccharomyces cerevisiae (酵母) 细胞中使用绿色光蛋白 (GFP) 记者.
- 评估了不同非结构化和结构化5' UTR长度对蛋白质合成的影响.
- 引入了关键翻译RNA基酶 (eIF4A,Ded1) 和启动因子 (eIF4G,eIF4B,eIF3g,eIF3i) 的功能丧失突变.
主要成果:
- 非结构化的5' UTR长度的数量级变化对蛋白质合成有适度的影响,这表明扫描不是限制速度的.
- 在5' UTR内的二次结构显著抑制了翻译.
- RNA基酶和启动因子中的突变减少了翻译,特别是在结构化的5' UTR 中,但基酶并没有限制40S运动的速度.
结论:
- 一维扩散,而不是酶驱动的转位,主要驱动40S子单元扫描沿着酵母的mRNA5' UTR进行扫描.
- RNA螺旋酶eIF4A和Ded1对于40S招募和解二次结构至关重要,但不限制扫描速率.
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