HIV-1 cap epigenetic modification

Project summary HIV-1 is made of proteins and RNA. The instructions to make all HIV proteins in proper amounts are presented on mRNAs that are 5'-capped. The 5'-cap of HIV-1 mRNAs gains chemical modifications that bolster HIV proliferation significantly. Preliminary revealed that ABX464, a new generation of HIV drug that compromises replication of HIV clinical isolates without positive selection for drug resistance, abrogated the modified cap in HIV mRNAs. The proposed interdisciplinary investigation will characterize the molecular details regulating HIV-1 cap hypermethylation using ABX464 as a novel molecular probe. ABX464 does not directly interact with Rev nor interfere with Rev/RRE interaction, and has been proposed to inhibit Rev:CBC interaction. The hypothesis is that Rev and RNA helicase A recognize structural elements in the proviral RNA and together bind TGS1 for cap hypermethylation that licenses the mRNA to enter translation pathways to make HIV-1 proteins in the right amounts. To address the hypothesis, three aims are proposed that evaluate the role of cap hypermethylation in HIV proliferation and systemic chronic immune activation, and characterize the molecular interactions for cap epigenetic modification. Aim 1. What are the viral and host protein-interaction framework for 5'- cap epigenetic modification and the subsequent balanced HIV proviral RNA expression? Aim 2. Are the molecular interactions for cap epigenetic modification conserved in primary T cells, monocyte-derived macrophages, and does the cap epigenetic modification affect host chronic immune activation? Aim 3. What RNA structural elements and RNA:protein interaction are necessary for the HIV cap epigenetic modification? The comparative studies with ABX464 are expected to pave the way for the future development of novel antiviral therapies targeting previously underestimated pathways.