The La protein functions redundantly with tRNA modification enzymes to ensure tRNA structural stability
The La protein functions redundantly with tRNA modification enzymes to ensure tRNA structural stability
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DOI：
10.1261/rna.2307206
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发表时间：
2006-04-01
期刊：
影响因子：
4.5
通讯作者：
Wolin, SL
中科院分区：
文献类型：
--
作者：
Copela, LA;Chakshusmathi, G;Wolin, SL
尽管La蛋白稳定来自核酸酶的新生前trna，影响前trna成熟的途径，并协助某些前trna的正确折叠，但它对于出芽和裂变酵母的生长都是必不可少的。在这里，我们证明了酿酒酵母La与tRNA修饰酶和其他在其生物发生过程中与tRNA接触的蛋白质共享功能冗余。在精氨酸基tRNA合成酶或tRNA修饰酶Trm1p突变的情况下，La对生长很重要。此外，两个假尿嘧啶合成酶PUS3和PUS4对于携带tRNA(CCG)（Arg）突变的菌株的生长很重要，并且当La在这些菌株中被删除时是必需的。Pus3p的缺失导致细胞核中氨基酰化突变体tRNA(CCG)（Arg）的积累，而Pus4p的缺失导致突变体tRNA的稳定性下降。有趣的是，突变型不稳定形式tRNA(CCG)（Arg）的降解不需要Trf4p聚(A)聚合酶，这表明酵母细胞具有多种tRNA降解途径。这些数据表明，La与tRNA修饰和与tRNA相关的蛋白质都具有冗余功能，以实现tRNA结构的稳定性和有效的生物发生。
Although the La protein stabilizes nascent pre-tRNAs from nucleases, influences the pathway of pre-tRNA maturation, and assists correct folding of certain pre-tRNAs, it is dispensable for growth in both budding and fission yeast. Here we show that the Saccharomyces cerevisiae La shares functional redundancy with both tRNA modification enzymes and other proteins that contact tRNAs during their biogenesis. La is important for growth in the presence of mutations in either the arginyl tRNA synthetase or the tRNA modification enzyme Trm1p. In addition, two pseudouridine synthases, PUS3 and PUS4, are important for growth in strains carrying a mutation in tRNA(CCG)(Arg) and are essential when La is deleted in these strains. Depletion of Pus3p results in accumulation of the aminoacylated mutant tRNA(CCG)(Arg) in nuclei, while depletion of Pus4p results in decreased stability of the mutant tRNA. Interestingly, the degradation of mutant unstable forms of tRNA(CCG)(Arg) does not require the Trf4p poly( A) polymerase, suggesting that yeast cells possess multiple pathways for tRNA decay. These data demonstrate that La functions redundantly with both tRNA modifications and proteins that associate with tRNAs to achieve tRNA structural stability and efficient biogenesis.