An epitranscriptomic switch at the 5´-UTR controls genome selection during HIV-1 genomic RNA packaging

During retroviral replication, the full-length RNA serves both as mRNA and genomic RNA (gRNA). While the simple retrovirus MLV segregates its full-length RNA into two functional populations, the HIV-1 full-length RNA was proposed to exist as a single population used indistinctly for protein synthesis or packaging. However, the mechanisms by which the HIV-1 Gag protein selects the two RNA molecules that will be packaged into nascent virions remain poorly understood. Here, we demonstrate that an epitranscriptomic switch involving the demethylation of adenosine residues present within HIV-1 5´-UTR regulates full-length RNA packaging. We further identified two conserved adenosines within the 5’-UTR that have a crucial structural and functional role and that are modulated by N6-methylation. While m6A deposition by METTL3/METTL14 onto the full-length RNA was associated with increased Gag synthesis and reduced packaging, FTO-mediated demethylation promotes the incorporation of the full-length RNA into viral particles. Interestingly, HIV-1 Gag associates with the RNA demethylase FTO in the nucleus contributing to full-length RNA demethylation. Finally, the specific inhibition of the FTO RNA demethylase activity suppressed HIV-1 full-length RNA packaging. Together, our data propose a novel epitranscriptomic mechanism allowing the selection of the full-length RNA molecules that will be used as viral genomes. We are providing RNAseq data from inputs (fragments of polyA RNA) and m6A-immunoprecipitated RNA from both HEK293T cells expressing HIV-1 NL4.3 as well as from purified viral particles. Two biological replicates are included. We also provide SHAPE-MaP data obtained using polyA RNA extracted from cell expressing HIV-1 NL4.3 and overexpressing d2EGPF (control) or METTL3/14.