Recombinant protein synthesis in Chinese hamster ovary cells using a vaccinia virus/bacteriophage T7 hybrid expression system.
The vaccinia virus/bacteriophage T7 expression system was adapted to Chinese hamster ovary (CHO) cells. Vaccinia virus undergoes abortive infection in CHO cells, which is characterized by a sharp reduction in protein synthesis at the stage of viral intermediate gene expression. We determined that expression of a T7 promoter-regulated chloramphenicol acetyltransferase gene was at least 20 times more efficient in permissive BS-C-1 than in CHO cells. The encephalomyocarditis virus 5'-untranslated region, which confers cap-independent translatability to mRNA, stimulated recombinant protein synthesis by 10-fold in both cell lines, maintaining the advantage of the BS-C-1 cells over CHO cells. Since the cowpox virus hr gene overcomes vaccinia virus host range restriction in CHO cells, we constructed a recombinant virus that carries an intact hr gene in addition to the T7 RNA polymerase gene. With this virus, synthesis of T7 RNA polymerase was enhanced and production of a recombinant protein occurred in CHO cells at the level observed in permissive cell lines. Extension of the vaccinia virus/bacteriophage T7 expression system to CHO cells should be of wide interest, as these cells have advantages for preparation of recombinant proteins in research and biotechnology.
Ramsey-Ewing
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Laboratory of Viral Diseases, NIAID, National Institutes of Health, Bethesda, Maryland 20892, USA.
Moss
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B
D000818:Animals; D017123:Bacteriophage T7 / Q000235:genetics*; D016466:CHO Cells; D002460:Cell Line; D015500:Chloramphenicol O-Acetyltransferase / Q000235:genetics / Q000378:metabolism; D002522:Chlorocebus aethiops; D003001:Cloning, Molecular; D006224:Cricetinae; D003412:Cricetulus; D005822:Genetic Vectors; D006367:HeLa Cells; D006801:Humans; D014176:Protein Biosynthesis; D012315:RNA Caps; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics*; D014616:Vaccinia virus / Q000235:genetics*
D012315:RNA Caps; D011994:Recombinant Proteins; D015500:Chloramphenicol O-Acetyltransferase