A human immunodeficiency virus Env inducible transcription system to examine consequences of gp120 expression

According to several studies, the HIV-1 envelope gp120 protein and the co-r eceptor CXCR4 play an essential role in HIV-1 induced cell toxicity. Charac terisation of the CD4-independent m7NDK isolate provided the opportunity of studying the effects of direct interactions between m7NDK gp120 and CXCR4. Therefore, an inducible expression system was designed enabling synthesis of HIV-1 Env proteins upon doxycycline induction. Analysis of the expressio n of the env gene of the m7NDK HIV-1 isolate revealed, unexpectedly, that e ven long-term expression of m7NDK gp120 did not result in cytotoxycity in C XCR4-positive or -negative cell lines. This is the first report of a CD4-in dependent HIV-1-protein inducible expression regulated through the Tet-On s ystem and by an alternative splicing. Env inducible expression cell lines c ould constitute a useful cellular tool to undertake analysis of HIV Env pro tein expression. (C) 2001 Elsevier Science B.V. All rights reserved.