bcl-2 expression in Spodoptera Frugiperda Sf-9 and Trichoplusia Ni BTI-Tn-5B1-4 insect cells: Effect on recombinant protein expression and cell viability

✍ Scribed by Christine Mitchell-Logean; David W. Murhammer

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 254 KB
• Volume: 56
• Category: Article
• ISSN: 0006-3592
• DOI: 10.1002/(sici)1097-0290(19971120)56:4<380::aid-bit4>3.0.co;2-k

✦ Synopsis

The effect of bcl-2 expression on cell viability and recombinant protein synthesis was investigated in the Spodoptera frugiperda Sf-9 and Trichoplusia ni BTI-Tn-5B1-4 (High Five™) insect cell lines. It was found that coinfection with a baculovirus expressing bcl-2 [Autographa californica nuclear polyhedrosis virus (AcNPV)-bcl2] extended the life span of High Five™ cells but not Sf-9 cells when compared to infection with recombinant baculoviruses expressing either human tissue plasminogen activator (AcNPV-tPA) or Escherichia coli ␤-galactosidase (AcNPV-␤gal). Similar results were obtained in coinfection experiments; i.e., AcNPV-bcl2 coinfection increased the life span of High Five™ cells over that of cells infected with either AcNPV-tPA or AcNPV-␤gal alone, but they did not affect the life span of coinfected Sf-9 cells. Coinfection of Sf-9 cells with AcNPV-bcl2 and AcNPV-␤gal resulted in a decrease in the maximum ␤-gal expression levels of over 90% when compared to infection with AcNPV-␤gal alone. A similar trend was found in the ␤-gal mRNA levels. Coinfection also resulted in a reduced ␤gal expression level in High Five™ cells, but the reduction was consistent with what would be expected when two recombinant viruses compete for use of the cellular machinery. In contrast to the inhibitory effect of AcNPV-bcl2 coinfection on ␤gal expression, t-PA expression levels were either not affected (Sf-9 cells) or were increased 50% (High Five™ cells) over those obtained by infection with AcNPV-tPA alone. These results support the hypotheses that bcl-2 can inhibit transcription of genes under polyhedrin promoter control and that ␤-gal expression levels, but not t-PA expression levels, are controlled at the transcriptional level.