Comprehensive mutational analysis of yeast DEXD/H box RNA helicases required for small ribosomal subunit synthesis
Comprehensive mutational analysis of yeast DEXD/H box RNA helicases required for small ribosomal subunit synthesis
复制标题
DOI：
10.1128/mcb.26.4.1183-1194.2006
复制
发表时间：
2006-02-01
影响因子：
5.3
通讯作者：
Baserga, SJ
中科院分区：
文献类型：
--
作者：
Granneman, S;Bernstein, KA;Baserga, SJ
前rRNA加工所需的17个假定的RNA解旋酶被预测通过驱动前乳糖体内的结构重排在核糖体生物发生中发挥关键作用。为了更好地了解这些蛋白质的功能，我们在参与18S rRNA合成的五个可能的RNA解旋酶中产生了一系列突变，并分析了它们对细胞生长和前rRNA加工的影响。我们的结果定义了保守基序中重要的功能残基，并表明当在野生型背景下过度表达时，预测的ATP结合-水解基序中的致命突变通常会在体内产生显性的负面表型。我们表明，显性负突变推迟了35S前-rRNA的处理，并导致通常具有低稳定水平的前-rRNA物种的积累。我们的综合结果表明，并不是所有的保守结构域在每个蛋白质中的功能都相同，这表明RNA解旋酶可能在核糖体生物发生中具有不同的生化特性和不同的作用。
The 17 putative RNA helicases required for pre-rRNA processing are predicted to play a crucial role in ribosome biogenesis by driving structural rearrangements within preribosomes. To better understand the function of these proteins, we have generated a battery of mutations in five putative RNA helicases involved in 18S rRNA synthesis and analyzed their effects on cell growth and pre-rRNA processing. Our results define functionally important residues within conserved motifs and demonstrate that lethal mutations in predicted ATP binding-hydrolysis motifs often confer a dominant negative phenotype in vivo when overexpressed in a wild-type background. We show that dominant negative mutants delay processing of the 35S pre-rRNA and cause accumulation of pre-rRNA species that normally have low steady-state levels. Our combined results establish that not all conserved domains function identically in each protein, suggesting that the RNA helicases may have distinct biochemical properties and diverse roles in ribosome biogenesis.