Investigation of RNA transcripts containing HIV-1 packaging signal sequences as HIV-1 antivirals: generation of cell lines resistant to HIV-1.

Based on the success of RNA decoy approaches using RRE and TAR sequences to inhibit HIV-1 replication, we studied the ability of HIV-1 packaging signal sequences to interfere with viral RNA encapsidation and formation of infectious particles. We made a variety of plasmid constructs in which the sequence context or number of repeats of the viral packaging signal was varied, and investigated the ability of these transcripts to inhibit replication of HIV-1 in stably transfected Jurkat T lymphocytes. We found that certain lines showed strong inhibition of HIV-1 replication, an effect that persisted at high input amounts of virus and significantly delayed viral replication for up to 4 weeks. An investigation of the mechanism of inhibition revealed that in these cell lines the packaging efficiency of the genomic HIV-1 transcript was unaffected. Further studies identified an antiviral effect on both HIV-1 and HIV-2 that did not correlate with decoy expression, and was substantially independent of CD4 expression or cellular proliferative capacity. Study of these resistant cell lines may lead to new insights into mechanisms of inhibition of HIV-1 replication.