Grandi Paola, Rybin Vladimir, Bassler Jochen, Petfalski Elisabeth, Strauss Daniela, Marzioch Martina, Schäfer Thorsten, Kuster Bernhard, Tschochner Herbert, Tollervey David, Gavin Anne Claude, Hurt Ed
Cellzome AG, Meyerhofstrasse 1, 69117, Heidelberg, Germany
Mol Cell. 2002 Jul;10(1):105-15. doi: 10.1016/s1097-2765(02)00579-8.
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 non-ribosomal 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.
我们报道了早期前核糖体颗粒的特征。十二个TAP标签标记的组分均显示核仁定位，在蔗糖梯度上沉降于约90S，并且与35S前体rRNA和U3 snoRNA共沉淀。共沉淀出35种非核糖体蛋白，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前核糖体组分中的突变损害了40S亚基的组装和输出。令人惊讶的是，在90S前核糖体中几乎未鉴定出最近表征的前60S核糖体的组分。我们得出结论，40S合成机制主要与35S前体rRNA因子相关，而60S亚基合成所需的因子大多在后期结合，显示出结合方面意想不到的二分法。
