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研究阐明90S前核糖体转化为原始40S亚基过程
作者:小柯机器人 发布时间:2020/9/18 14:32:05

德国慕尼黑大学Roland Beckmann和德国慕尼黑大学Ed Hurt研究组合作取得一项新突破。他们阐明了90S前核糖体转化为原始40S亚基过程。相关论文于2020年9月18日发表在《科学》杂志上。

他们通过沿酵母中该途径中间体的生化和冷冻电镜分析阐明了90S前核糖体转化为原始40S亚基过程。首先,重塑RNA解旋酶Dhr1与90S前核糖体结合,然后在位点A1处进行Utp24内切核酸酶驱动的RNA切割,从而从18S核糖体RNA中分离5'-外部转录间隔区(ETS)。接下来,5'-ETS和90S装配系数被移开,但这是顺序发生的,不是整体发生的。

最终,原始的前40S出现,仍然保留了包括Dhr1在内的90S因子,现在已经准备好释放最终的小核仁U3-18S RNA杂合子。他们的数据阐明了从90S到40S之前难以理解的过渡,并阐明了大型核糖核蛋白组装和重塑的原理。

据了解,小型核糖体亚基的产生最初需要形成90S前体,然后再重组为原始前40S亚基。

附:英文原文

Title: 90S pre-ribosome transformation into the primordial 40S subunit

Author: Jingdong Cheng, Benjamin Lau, Giuseppe La Venuta, Michael Ameismeier, Otto Berninghausen, Ed Hurt, Roland Beckmann

Issue&Volume: 2020/09/18

Abstract: Production of small ribosomal subunits initially requires the formation of a 90S precursor followed by an enigmatic process of restructuring into the primordial pre-40S subunit. We elucidate this process by biochemical and cryo–electron microscopy analysis of intermediates along this pathway in yeast. First, the remodeling RNA helicase Dhr1 engages the 90S pre-ribosome, followed by Utp24 endonuclease–driven RNA cleavage at site A1, thereby separating the 5′-external transcribed spacer (ETS) from 18S ribosomal RNA. Next, the 5′-ETS and 90S assembly factors become dislodged, but this occurs sequentially, not en bloc. Eventually, the primordial pre-40S emerges, still retaining some 90S factors including Dhr1, now ready to unwind the final small nucleolar U3–18S RNA hybrid. Our data shed light on the elusive 90S to pre-40S transition and clarify the principles of assembly and remodeling of large ribonucleoproteins.

DOI: 10.1126/science.abb4119

Source: https://science.sciencemag.org/content/369/6510/1470

期刊信息
Science:《科学》,创刊于1880年。隶属于美国科学促进会,最新IF:41.037