Department of Molecular Genetics, Weizmann Institute of Science, Rehovot, Israel.
PLoS Genet. 2014 Jan;10(1):e1004084. doi: 10.1371/journal.pgen.1004084. Epub 2014 Jan 16.
Deciphering the architecture of the tRNA pool is a prime challenge in translation research, as tRNAs govern the efficiency and accuracy of the process. Towards this challenge, we created a systematic tRNA deletion library in Saccharomyces cerevisiae, aimed at dissecting the specific contribution of each tRNA gene to the tRNA pool and to the cell's fitness. By harnessing this resource, we observed that the majority of tRNA deletions show no appreciable phenotype in rich medium, yet under more challenging conditions, additional phenotypes were observed. Robustness to tRNA gene deletion was often facilitated through extensive backup compensation within and between tRNA families. Interestingly, we found that within tRNA families, genes carrying identical anti-codons can contribute differently to the cellular fitness, suggesting the importance of the genomic surrounding to tRNA expression. Characterization of the transcriptome response to deletions of tRNA genes exposed two disparate patterns: in single-copy families, deletions elicited a stress response; in deletions of genes from multi-copy families, expression of the translation machinery increased. Our results uncover the complex architecture of the tRNA pool and pave the way towards complete understanding of their role in cell physiology.
解析 tRNA 库的结构是翻译研究中的一个主要挑战，因为 tRNA 控制着该过程的效率和准确性。针对这一挑战，我们在酿酒酵母中创建了一个系统的 tRNA 缺失文库，旨在剖析每个 tRNA 基因对 tRNA 库和细胞适应性的特定贡献。利用这一资源，我们观察到大多数 tRNA 缺失在丰富培养基中没有明显的表型，但在更具挑战性的条件下，观察到了其他表型。tRNA 基因缺失的稳健性通常通过在 tRNA 家族内部和之间进行广泛的备用补偿来实现。有趣的是，我们发现，在 tRNA 家族内部，携带相同反密码子的基因可能对细胞适应性有不同的贡献，这表明基因组周围环境对 tRNA 表达的重要性。对 tRNA 基因缺失的转录组响应进行特征分析揭示了两种截然不同的模式：在单拷贝家族中，缺失会引发应激反应；在多拷贝家族基因缺失中，翻译机制的表达增加。我们的研究结果揭示了 tRNA 库的复杂结构，并为全面了解它们在细胞生理学中的作用铺平了道路。
