研究闡明90S前核糖體轉化為原始40S亞基過程
作者：
小柯機器人發布時間：2020/9/18 14:32:05
德國慕尼黑大學Roland Beckmann和德國慕尼黑大學Ed Hurt研究組合作取得一項新突破。他們闡明了90S前核糖體轉化為原始40S亞基過程。相關論文於2020年9月18日發表在《科學》雜誌上。
他們通過沿酵母中該途徑中間體的生化和冷凍電鏡分析闡明了90S前核糖體轉化為原始40S亞基過程。首先，重塑RNA解旋酶Dhr1與90S前核糖體結合，然後在位點A1處進行Utp24內切核酸酶驅動的RNA切割，從而從18S核糖體RNA中分離5'-外部轉錄間隔區（ETS）。接下來，5'-ETS和90S裝配係數被移開，但這是順序發生的，不是整體發生的。
最終，原始的前40S出現，仍然保留了包括Dhr1在內的90S因子，現在已經準備好釋放最終的小核仁U3-18S RNA雜合子。他們的數據闡明了從90S到40S之前難以理解的過渡，並闡明了大型核糖核蛋白組裝和重塑的原理。
據了解，小型核糖體亞基的產生最初需要形成90S前體，然後再重組為原始前40S亞基。
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
Science：《科學》，創刊於1880年。隸屬於美國科學促進會，最新IF：41.037