title: Synthesis of Semliki-forest virus in polyamine-depleted baby-hamster kidney cells.
abstract: The role of polyamines in macromolecular synthesis has been studied using the synthesis of Semliki-Forest virus (SF virus) in normal and alpha-difluoromethylornithine-treated baby-hamster kidney (BHK21) cells as a model system. The activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase, the rate-limiting enzymes in polyamine biosynthesis, decreased rapidly in mock- and SF-virus-infected cells, indicating that virus production in BHK21 cells was not dependent on polyamines formed after infection. A prolonged treatment of BHK21 cells with alpha-difluoro-methylornithine, a specific inhibitor of polyamine synthesis, resulted in a marked inhibition of the initial rate of virus production, which appeared 72 h after the beginning of the treatment. This inhibition was reversed by putrescine, spermidine and spermine, and at last partially by several other diamines and polyamine homologues. Polyamine-depletion also markedly reduced viral RNA polymerase activity in SF-virus infected cells. Addition of spermidine to the culture medium rapidly increased viral RNA polymerase activity in the inhibitor-treated cells but had no effect on the enzyme activity when added directly to the assay mixture. The results indicated that polyamines are needed for maximum initial rate of SF-virus replication and suggest that the inhibition of virus production in polyamine-depleted cells is at least partly due to malfunction of the protein-synthetic machinery of the host cell.
mesh_terms: D000818:Animals; D002460:Cell Line; D006224:Cricetinae; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D000518:Eflornithine; D007668:Kidney / Q000166:cytology / Q000378:metabolism*; D007700:Kinetics; D009952:Ornithine / Q000031:analogs & derivatives / Q000494:pharmacology; D011073:Polyamines / Q000378:metabolism* / Q000494:pharmacology; D012367:RNA, Viral / Q000096:biosynthesis*; D012672:Semliki forest virus / Q000187:drug effects / Q000378:metabolism*; D014162:Transfection; D014779:Virus Replication / Q000187:drug effects
chemical_list: D011073:Polyamines; D012367:RNA, Viral; D009952:Ornithine; D012321:DNA-Directed RNA Polymerases; D000518:Eflornithine