An ornithine decarboxylase-deficient mutant of Chinese hamster ovary cells.

摘要: We have selected a mutant of Chinese hamster ovary cells that is severely deficient in ornithine decarboxylase activity and auxotrophic for putrescine. The we obtained (C54) has only 3% the maximum inducible parental rate incorporation [3H]ornithine into acid-soluble material correspondingly reduced. defect was recessive somatic cell hybrids. requires at least 10(-5) M putrescine medium to maintain normal growth rate. Spermidine spermine can also serve as polyamine source, very high (millimolar) concentrations support In absence supplementation stop growing after about 3 population doublings begin die 5 or 6 days. intracellular spermidine are depleted 24 48 h, respectively. Spermine levels remain essentially constant 4 Unexpectedly, Km enzyme from consistently somewhat lower than wild type cells. It possible but not yet certain result mutation structural gene coding decarboxylase.