tRNAs as regulators in gene expression
tRNAs as regulators in gene expression
复制标题
DOI：
10.1007/s11427-009-0039-y
复制
发表时间：
2009-03
期刊：
影响因子：
--
通讯作者：
Yan Li;Hui Zhou
中科院分区：
文献类型：
--
作者：
Yan Li;Hui Zhou
转运RNA（transfer RNA，tRNA）是蛋白质合成的核心分子，它将DNA中的遗传信息翻译成蛋白质的氨基酸序列，起到“衔接”分子的作用。然而，近年来，各种研究表明，tRNA除了参与蛋白质合成外还有其他功能。当受到一定的营养胁迫时，tRNA改变氨酰化水平，使其不带电荷，这些不带电荷的tRNA作为效应分子调节全局基因表达，从而使受胁迫的生物体应对不利的环境胁迫。在芽殖酵母和某些哺乳动物细胞中，成熟tRNA从细胞质到细胞核的逆行运动作为细胞核内监视系统的机制，以继续监测tRNA的完整性。另一方面，这种逆行作用有效地降低了营养饥饿条件下的整体蛋白质合成水平。最近，各种出版物表明，tRNA不是绝对意义上的稳定分子。在一定的生理或环境胁迫下，它们在反密码子环或反密码子左臂被特异性地切割成不同长度的片段，这些切割并不是无意义的随机降解现象。相反，可能会产生一类新的信号分子，如tRNA半分子或sitRNAs，它们与全局基因表达的调节密切相关。对tRNA的调控功能的研究是一个前沿领域，旨在揭示tRNA的结构和功能的多样性以及它们在遗传信息表达中的重要功能。
Transfer RNAs (tRNAs) hold a central place in protein synthesis by interpreting the genetic information stored in DNA into the amino acid sequence of protein, thus functioning as “adaptor” molecules. In recent years, however, various studies have shown that tRNAs have additional functions beyond participating in protein synthesis. When suffering from certain nutritional stresses, tRNAs change the level of aminoacylation to became uncharged, and these uncharged tRNAs act as effector molecules to regulate global gene expression, so that the stressed organism copes with the adverse environmental stresses. In budding yeast and certain mammalian cells, the retrograde movement of mature tRNAs from cytoplasm to nucleus serves as a mechanism for the surveillance system within the nucleus to continue monitoring the integrity of tRNAs. On the other hand, this retrograde action effectively reduces the global protein synthesis level under conditions of nutritional starvation. Quite recently, various publications have shown that tRNAs are not stable molecules in an absolute sense. Under certain physiological or environmental stresses, they are specifically cleaved into fragments of different lengths in the anticodon loop or anticodon left arm. These cleavages are not a meaningless random degradation phenomenon. Instead, a novel class of signal molecules such as tRNA halves or sitRNAs may be produced, which are closely correlated with the modulation of global gene expression. Investigation of the regulatory functions of tRNAs is a frontier, which seeks to reveal the structural and functional diversity of tRNAs as well as their vital functions during the expression of genetic information.