Schizosaccharomyces pombe, unlike Saccharomyces cerevisiae, may not directly regulate nuclear-cytoplasmic transport of spliced tRNAs in response to nutrient availability.
Eukaryotic cells adapt to changes in nutrient levels by regulating key processes, such as gene transcription, ribosome biogenesis, and protein translation. Several studies have shown that nuclear export of tRNAs is also regulated in Saccharomyces cerevisiae and rat hepatoma H4IIE cells during nutrient stress. However, recent studies suggest that nutrient stress does not affect nuclear tRNA export in several mammalian cell lines, including rat hepatoma H4IIE. Furthermore, in contrast to previous studies, data reported more recently established that nuclear export of mature tRNAs derived from intron-containing pre-tRNAs, but not mature tRNAs made from intronless precursors, is affected by nutrient stress in several species of Saccharomyces, but not in the yeast Kluyveromyces lactis . Here, we provide evidence suggesting that Schizosaccharomyces pombe, like mammalian cells and K. lactis, but unlike Saccharomyces, do not directly regulate nuclear export of mature tRNAs made from intron-containing pre-tRNAs in response to nutrient stress. These studies collectively suggest that regulation of nuclear export of spliced tRNAs to the cytoplasm in response to nutrient availability may be limited to the genus Saccharomyces, which unlike other yeasts and higher eukaryotes produce energy for fermentative growth using respiration-independent pathways by downregulating the citric acid cycle and the electron transport chain.
Pierce JB, Mangroo D