90S pre-ribosomes include the 35S pre-rRNA, the U3 snoRNP, and 40S subunit processing factors but predominantly lack 60S synthesis factors
90S pre-ribosomes include the 35S pre-rRNA, the U3 snoRNP, and 40S subunit processing factors but predominantly lack 60S synthesis factors
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DOI：
10.1016/s1097-2765(02)00579-8
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发表时间：
2002-07-01
期刊：
影响因子：
16
通讯作者：
Hurt, E
中科院分区：
文献类型：
--
作者：
Grandi, P;Rybin, V;Hurt, E
我们报道了早期核糖体前体颗粒的特性。12种带有串联亲和纯化（TAP）标签的组分均显示出核仁定位，在蔗糖梯度中约90S处沉降，并且能共沉淀35S前核糖体RNA（pre - rRNA）和U3小核仁RNA（snoRNA）。35种非核糖体蛋白被共沉淀，包括与U3相关的蛋白（Nop56p、Nop58p、Sof1p、Rrp9、Dhr1p、Imp3p、Imp4p和Mpp10p）以及18S rRNA合成所需的其他因子（Nop14p、Bms1p和Krr1p）。90S核糖体前体组分的突变会损害40S亚基的组装和输出。引人注目的是，在90S核糖体前体中很少发现近期所描述的60S核糖体前体的组分。我们得出结论：40S合成机制主要与35S前rRNA因子相关联，而60S亚基合成所需的因子大多在后期结合，这显示出一种意想不到的结合二分性。
We report the characterization of early pre-ribosomal particles. Twelve TAP-tagged components each showed nucleolar localization, sedimented at approximately 90S on sucrose gradients, and coprecipitated both the 35S pre-rRNA and the U3 snoRNA. Thirty-five nonribosomal proteins were coprecipitated, including proteins associated with U3 (Nop56p, Nop58p, Sof1p, Rrp9, Dhr1p, Imp3p, Imp4p, and Mpp10p) and other factors required for 18S rRNA synthesis (Nop14p, Bms1p, and Krr1p). Mutations in components of the 90S pre-ribosomes impaired 40S subunit assembly and export. Strikingly, few components of recently characterized pre-60S ribosomes were identified in the 90S pre-ribosomes. We conclude that the 40S synthesis machinery predominately associates with the 35S pre-rRNA factors, whereas factors required for 60S subunit synthesis largely bind later, showing an unexpected dichotomy in binding.