Induction and reversion of asparagine auxotrophs in CHO-K1 and V79 cells.
Two asparagine-dependent clones (2002-103 and 2002-109) were obtained from CHO-K1 cells by treatment with EMS followed by a BrdU-black light selection procedure; an additional ASP- clone (2293-343) was isolated similarly from V79-56 cells. All three clones show a low rate of spontaneous reversion which is increased somewhat by exposure to EMS. Two of the variant clones (2002-103 and 2002-109) are converted in high frequency to asparagine independence by treatment with 5-azacytidine, while 2293-343 cells show no significant induction after similar exposure. All three ASP- clones were found by hybrid analyses to belong to the same complementation group. Treatment of hybrids constructed between 2002-103 or 2002-109 X 2293-343 with 5-azacytidine resulted in high-frequency induction of asparagine independence. Thus, the potential for response to 5-azacytidine in such hybrids by reversion to asparagine independence is dominant or codominant, with no suppressor effect in hybrids from the nonresponsive parent line.
D000818:Animals; D001216:Asparagine / Q000494:pharmacology*; D001217:Aspartate-Ammonia Ligase / Q000235:genetics / Q000378:metabolism; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D009154:Mutation
D001216:Asparagine; D001217:Aspartate-Ammonia Ligase