Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario, Canada.
Plant Signal Behav. 2011 Aug;6(8):1183-8. doi: 10.4161/psb.6.8.15690. Epub 2011 Aug 1.
Cells respond to nutrient stress by regulating gene transcription and various key metabolic processes, including ribosome biogenesis and protein synthesis. Several studies have shown that yeasts and mammalian cells also regulate export of tRNAs from the nucleus to the cytosol in response to nutrient stress. However, nuclear export of tRNA in mammalian cells during nutrient stress is controversial, as it has been recently shown that nuclear-cytoplasmic transport of tRNAs in several mammalian cell lines is not affected by nutrient deprivation. Furthermore, contrary to previous studies, data reported recently indicate that nuclear export of mature tRNAs derived from intron-containing precursor tRNAs, but not tRNAs made from intronless precursors, is affected by nutrient availability in several Saccharomyces species, although not in Kluyveromyces lactis and Schizosaccharomyces pombe. Here, we report that plants, like mammals and some yeasts, but unlike Saccharomyces, do not directly regulate nuclear export of tRNA in response to nutrient stress, indicating that this process is not entirely conserved among evolutionarily diverse organisms.
细胞通过调节基因转录和各种关键代谢过程（包括核糖体生物发生和蛋白质合成）来响应营养胁迫。几项研究表明，酵母和哺乳动物细胞也响应营养胁迫调节 tRNA 从核输出到细胞质。然而，在营养胁迫下哺乳动物细胞中 tRNA 的核输出存在争议，因为最近的研究表明，几种哺乳动物细胞系中 tRNA 的核质转运不受营养剥夺的影响。此外，与先前的研究相反，最近报告的数据表明，在几种酿酒酵母物种中，成熟 tRNA 从包含内含子的前体 tRNA 的核输出受到营养可用性的影响，但来自无内含子前体的 tRNA 不受影响，尽管 Kluyveromyces lactis 和 Schizosaccharomyces pombe 不受影响。在这里，我们报告说，植物与哺乳动物和一些酵母一样，但与酿酒酵母不同，它们不会直接响应营养胁迫调节 tRNA 的核输出，这表明这个过程在进化上多样化的生物体中并非完全保守。
