Regulated expression of HIV-1 Rev function in mammalian cell lines

In order to facilitate further investigation of Rev function, we have gener ated two systems for the inducible expression of Rev in mammalian cell line s (HeLa and U937) using either a tetracycline-regulated promoter or fusion of Rev to a modified form of the hormone binding domain of the estrogen rec eptor. In the case of the fusion of Rev to the modified hormone binding dom ain of the estrogen receptor, we demonstrated induction of Rev function in response to tamoxifen administration to levels comparable to that of the un modified Rev protein. Subsequently, U937 lines were generated that retained the observed pattern of hormone-dependent function of the Rev fusion prote in. In the case of the tetracycline-regulated system, cell lines (both HeLa and U937) were generated that displayed tight regulation of Rev. In the ca se of the HeLa cell lines, they were used for the subsequent generation of stable cell lines expressing either HIV-1 env or chloramphenicol acetyl tra nsferase (CAT) in a Rev-dependent fashion. Using the latter cell lines, we demonstrate the ability to control Rev expression over a broad concentratio n range and find that, as soon as Rev expression is detectable, induction o f Rev-dependent gene expression is also observed.