title: Constitutive, long-term production of human interferons by hamster cells containing multiple copies of a cloned interferon gene.
abstract: Hybrid plasmids containing the mouse dihydrofolate reductase (dhfr) and a human interferon (either IFN-alpha 5 or IFN-gamma) coding sequence under the control of viral promoters were transfected into dhfr- Chinese hamster ovary (CHO) cells. dhfr+ colonies produced IFN at 10-1000 units X ml-1 X day-1. Clones selected in methotrexate had a 20-50-fold increase in the IFN-alpha 5 and dhfr DNA and mRNA content and secreted IFN at 20,000-100,000 units X ml-1 X day-1. SDS-polyacrylamide gel electrophoresis of partially purified 35S-HuIFN-gamma from CHO cells showed a multiple of labeled bands with a mobility corresponding to 22,400 to 23,400 daltons which was absent in the supernatants of non-transformed CHO cells. The higher apparent molecular weight of human IFN-gamma from CHO cells as compared to that of human IFN-gamma from E. coli (about 18,800) suggests that the former was glycosylated.
mesh_terms: D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D004262:DNA Restriction Enzymes; D005260:Female; D005796:Genes; D006801:Humans; D007370:Interferon Type I / Q000235:genetics*; D007371:Interferon-gamma / Q000235:genetics*; D007372:Interferons / Q000302:isolation & purification; D008715:Methionine / Q000378:metabolism; D008970:Molecular Weight; D009693:Nucleic Acid Hybridization; D010053:Ovary; D010957:Plasmids; D012333:RNA, Messenger / Q000235:genetics; D013762:Tetrahydrofolate Dehydrogenase / Q000235:genetics
chemical_list: D007370:Interferon Type I; D012333:RNA, Messenger; D007371:Interferon-gamma; D007372:Interferons; D008715:Methionine; D013762:Tetrahydrofolate Dehydrogenase; D004262:DNA Restriction Enzymes