Post-transcriptional regulation of glutamyl-prolyl-tRNA synthetase in rat salivary gland.
Treatment of rats with isoproterenol resulted in elevated levels of prolyl- and glutamyl-tRNA synthetase activities in the parotid and submandibular glands. This increase in enzyme activity was accompanied by an increase in the bi-functional glutamyl-prolyl-tRNA synthetase and of a low molecular weight form of prolyl-tRNA synthetase. Isoproterenol also induced the synthesis of proline-rich glycoproteins in the parotid and submandibular glands. Withdrawal from the drug was accompanied by a decline in prolyl- and glutamyl-tRNA synthetase activities and by a decline in the levels of proline-rich glycoproteins in the salivary gland. During the time course of isoproterenol treatment, little change in the levels of mRNA encoding the bi-functional glutamyl-prolyl-tRNA synthetase was detected by Northern blot analysis. These results indicate that the synthesis of glutamyl-prolyl-tRNA synthetase is regulated at a post-transcriptional step and that the synthesis of this bifunctional protein may be linked to the utilization of proline and glutamic acid in protein synthesis.
Ting
S M
SM
Department of Biochemistry and Molecular Biology, Medical College of Ohio, Toledo 43699-0008.
Dignam
J D
JD
D000604:Amino Acyl-tRNA Synthetases / Q000235:genetics*; D000818:Animals; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D005796:Genes; D005975:Glutamate-tRNA Ligase / Q000235:genetics*; D005971:Glutamates / Q000378:metabolism; D007545:Isoproterenol / Q000494:pharmacology*; D008297:Male; D011392:Proline / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012469:Salivary Glands / Q000201:enzymology*; D012471:Salivary Proteins and Peptides / Q000096:biosynthesis; D046249:Transfer RNA Aminoacylation
D005971:Glutamates; D012471:Salivary Proteins and Peptides; D011392:Proline; D000604:Amino Acyl-tRNA Synthetases; C100134:prolyl T RNA synthetase; D005975:Glutamate-tRNA Ligase; D007545:Isoproterenol