L-asparaginyl-tRNA synthetase and L-asparagine synthetase activities of L-asparaginase-sensitive and -resistant forms of the mouse Gardner lymphoma 6C3HED.
1. The mouse Gardner lymphoma 6C3HED was grown in ascites fluid in a form sensitive to the action of L-asparaginase (line 1), in another form which was resistant to L-asparaginase (line 2) and in a third form with partial sensitivity to L-asparaginase (line 3). 2. The L-asparaginyl-tRNA synthetase activities of extracts of the tumour cells, cultured both in the mouse and in vitro, were determined. Two of the lines, 1 and 3, in early passage numbers, showed a derepression mechanism involving L-asparagine. Mutation occurred with these lines resulting in the L-asparaginyl-tRNA synthetase activity of all the tumour cell lines being the same. 3. Cells of line 1 had low L-asparagine synthetase activity, which was unchanged by altering the supply of L-asparagine in vitro. Cells of lines 2 and 3 exhibited L-asparagine synthetase activities, which changed with the supply of L-asparagine. 4. It is not certain that L-asparagine synthetase activity of L-asparaginase-sensitive cells is controlled by L-asparaginyl-tRNA acting as a corepressor.
D000604:Amino Acyl-tRNA Synthetases / Q000378:metabolism*; D000818:Animals; D000970:Antineoplastic Agents; D001202:Ascitic Fluid / Q000378:metabolism; D001215:Asparaginase / Q000378:metabolism*; D001216:Asparagine / Q000096:biosynthesis; D001217:Aspartate-Ammonia Ligase / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D006736:Horses; D008025:Ligases / Q000378:metabolism*; D008223:Lymphoma / Q000201:enzymology*; D051379:Mice; D008809:Mice, Inbred C3H; D009374:Neoplasms, Experimental / Q000201:enzymology*; D013997:Time Factors
D000970:Antineoplastic Agents; D001216:Asparagine; D001215:Asparaginase; D008025:Ligases; D000604:Amino Acyl-tRNA Synthetases; D001217:Aspartate-Ammonia Ligase