Studies on the effect of the combined expression of anti-tat and anti-rev genes on HIV-1 replication

A series of retroviral vectors with potential anti-tat and anti-rev activity was developed. Vectors containing a tat trans-dominant negative mutant (tat(22/37)) and an RRE decoy in different positions, directed by the same promoter or by different promoters, were generated. Retroviral vectors containing tat 22/37 and the RevM10 transdominant negative mutant were also constructed. Jurkat cells were transduced with the recombinant retroviruses to produce monoclonal and polyclonal cultures. in these cell lines the recombinant proviruses were correctly integrated and expression of the inserted genes was detected by Northern blot or RT-PCR analysis. However, infection of these cell lines with HIV-1 showed that none of these recombinant constructs inhibited virus replication at a high multiplicity of infection (MOI). At a low MOI, two cell clones containing tat(22/37) and the RRE decoy in 3' position showed a long lasting protection against virus replication, in comparison to control cultures expressing tat(22/37) or RRE alone. Combination of tat and rev mutants was ineffective in inhibiting HIV-1 replication at both low and high MOIs. At a low MOI, HIV-1 replication was efficiently blocked in two cell clones expressing the RevM10 mutant alone. These results show a synergic effect of anti-tat and anti-rev molecules when the RRE sequence is cloned 3' to tat(22/37), suggesting the possibility of using this vector design to control HIV-1 replication.