title: Amplification of ornithine decarboxylase gene in response to polyamine deprivation in Chinese hamster ovary cells.
abstract: We have isolated from an arginase-deficient polyamine-dependent Chinese hamster ovary cell line a new mutant strain that has greatly increased ornithine decarboxylase activity. This enables the cells, in the absence of ornithine, to decarboxylate lysine into cadaverine (diaminopentane) that is further converted into N-(3-aminopropyl)cadaverine and N,N'-bis(3-aminopropyl)cadaverine. These unusual polyamines can support the growth of the cells without added polyamines derived from ornithine. Immunoreactive ornithine decarboxylase-like protein was clearly increased in the mutant cells but could not solely account for the greatly increased enzyme activity. Southern blot analysis of DNA hybridized to a plasmid carrying ornithine decarboxylase-cDNA revealed at least a 32-fold amplification of the ornithine decarboxylase gene. Ornithine decarboxylase-mRNA concentration was also highly increased in the cells. The half-life of the enzyme and the Km for ornithine were not altered from those of the parental cell line.
mesh_terms: D012437:Adenosylmethionine Decarboxylase / Q000378:metabolism; D000818:Animals; D002103:Cadaverine / Q000378:metabolism; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D000518:Eflornithine; D004591:Electrophoresis, Polyacrylamide Gel; D005260:Female; D005784:Gene Amplification; D007621:Karyotyping; D007700:Kinetics; D008239:Lysine / Q000378:metabolism; D009952:Ornithine / Q000031:analogs & derivatives / Q000378:metabolism; D009955:Ornithine Decarboxylase / Q000235:genetics* / Q000378:metabolism; D010053:Ovary / Q000201:enzymology*; D010957:Plasmids; D011073:Polyamines / Q000378:metabolism*; D012333:RNA, Messenger / Q000032:analysis; D013096:Spermine / Q000378:metabolism
chemical_list: D011073:Polyamines; D012333:RNA, Messenger; D013096:Spermine; D009952:Ornithine; D009955:Ornithine Decarboxylase; D012437:Adenosylmethionine Decarboxylase; D008239:Lysine; D002103:Cadaverine; D000518:Eflornithine