Synergistic Inhibition of HIV-1 Regulatory Function Using a Dual Expression shRNA Plasmid

HIV infection of CD4+ T Helper lymphocytes results in a gradual loss of immune competence, which ultimately leads to development of the acquired immune deficiency syndrome (AIDS). HIV-1 expresses two regulatory proteins, Tat and Rev, which act to upregulate viral transcription and facilitate mRNA transport enhancing the rate of translation. Inhibition of Tat and Rev have been shown to block virus replication. Therefore, Tat and Rev represent critical key points in the virus replication cycle. This study investigated the potential of RNA interference (RNAi) to inhibit these proteins using short hairpin RNAs (shRNAs). For this, plasmids expressing shRNAs targeting either Tat or Rev and a dual shRNA plasmid concurrently targeting both proteins, were evaluated using a Tat- and Rev-dependent luciferase assay. Results showed that although both individual shRNAs significantly reduced luciferase activity, dual shRNA plasmid exhibited a greater reduction in luciferase activity than either individual shRNA, indicating a synergistic effect.