VSV-G-pseudotyped retroviral packaging through adenovirus-mediated inducible gene expression.

It has been technically difficult to generate recombinant adenoviruses encoding genes for cytotoxic products such as vesicular stomatitis virus G-protein (VSV-G), which is too toxic for the host cells to allow adenoviral propagation. In our companion paper (Yoshida, Y., and Hamada, H., Biochem. Biophys. Res. Commun., 230, 426-430, 1997), a tetracycline-inducible adenovirus system is reported. The inducible expression system enabled us to generate recombinant adenoviruses encoding genes for the cytotoxic viral VSV-G product. In this study, we generated recombinant adenoviruses encoding VSV-G and MoMLV gag-pol genes, both under the tetracycline-controllable promoter, and attempted retroviral packaging. Simultaneous infection of these adenoviruses together with tetracycline-transactivator (NtTA) expression resulted in efficient VSVG-pseudotyped retroviral packaging. Adenovirus-mediated recombinant retrovirus generation will be useful in studies with various pseudotyped mutants, as well as in assays for retrovirus-related genes and their products.