The HIV-1 tat gene as a target for gene therapy and analysis of its role in cell proliferation

In order to block HIV-1 replication and reactivation from latency we constructed several retroviral vectors expressing tat transdominant negative mutants in the cysteine-rich domain, which is essential for tat transactivating function. Substitution of cysteine 22 with glycine generated a tat mutated protein (tat22) which was able to interfere with virus replication in Jurkat T cells. A double mutant, where cysteines 22 and 37 were replaced with glycine and serine respectively (tat22/37), was also created and shown to antagonize virus reactivation from latency in Jurkat cells chronically infected by HIV-1. Moreover, to study the role of the HIV-1 tat protein in vivo, we generated tat transgenic mice using a BK virus expression vector. BKV/tat transgenic mice developed skin lesions resembling the early stage of Kaposi's sarcoma, three types of tumors involving the skin (adenocarcinomas, leiomyosarcomas and squamous cell carcinomas), lymphomas, hepatocellular carcinomas and liver cell dys...