title: Control of specific transfer RNA concentrations in amino acid-deprived Friend leukemia cells operates at the level of RNA degradation.
abstract: In eukaryotes, the concentrations of specific tRNAs are closely correlated with the demands for their cognate amino acids in protein synthesis. To account for this phenomenon, we have proposed that the extent of aminoacylation of a given tRNA species in vivo controls the relative rate of synthesis or degradation of that species. Previously, we reported the Friend leukemia cells respond to deprivation of histidine, leucine, or tryptophan by specifically increasing the relative concentration of tRNAs cognate to the deprived amino acid (Weiser, K., and Litt, M. (1979) Eur. J. Biochem. 93, 295-300). In this paper, we show that this is also true for phenylalanine and we report studies of the relative rates of synthesis and degradation of tRNAPhe in phenylalanine-deprived and control cells. We find that deprivation of phenylalanine has no effect on the relative rate of synthesis of tRNAPhe, but does induce a decline in the relative rate of degradation of tRNAPhe which accounts quantitatively for the increase in its relative steady state concentration as measured by in vitro aminoacylation. We conclude that, in Friend leukemia cells, deacylated tRNA species are more stable than charged tRNA species.
mesh_terms: D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002460:Cell Line; D006639:Histidine / Q000378:metabolism; D007930:Leucine / Q000378:metabolism; D007942:Leukemia, Experimental / Q000378:metabolism*; D051379:Mice; D010649:Phenylalanine / Q000378:metabolism; D012343:RNA, Transfer / Q000378:metabolism*; D014364:Tryptophan / Q000378:metabolism; D014529:Uridine / Q000378:metabolism
chemical_list: D000596:Amino Acids; D010649:Phenylalanine; D006639:Histidine; D014364:Tryptophan; D012343:RNA, Transfer; D007930:Leucine; D014529:Uridine