Inhibition of HIV-1 replication by primer RNA packaging inhibitors

An essential step in the life cycle of human immunodeficiency virus type 1 (HIV-1) is the packaging of tRNA₃^Lys during viral assembly. This step, which requires the assembly of a ternary complex consisting of GagPol, mitochondrial lysyl-tRNA synthetase, and tRNA₃^Lys, is essential for the production of infectious viruses. Indeed, it allows the initiation of reverse transcription in the particles. In this work, we used an in vitro assay to isolate molecules from a chemical library that disrupt the interaction between the integrase domain of GagPol and mitochondrial lysyl-tRNA synthetase. The three selected molecules also inhibit HIV-1 replication in an ex vivo assay. The number of HIV-1 particles produced in the presence of the drugs is greatly reduced, with a half-maximal inhibitory concentration obtained at a drug concentration of 5 µM. In addition, we have shown that the few particles produced in the presence of the drugs exhibit significantly reduced infectivity, due to their inability to synthesize minus-strand strong stop cDNA. In parallel, the tRNA₃^Lys content of the particles obtained in the presence of drugs decreased significantly. The inability to package tRNA₃^Lys into virions results in replication-defective particles.IMPORTANCESeveral families of inhibitors have been selected to tackle the human immunodeficiency virus (HIV). Cell entry, reverse transcriptase, integrase, or protease is the most popular targets along the viral life cycle. During the budding step of the virus, the packaging of tRNA₃^Lys into particles, which serves as a primer for the initiation of reverse transcription in the virus, has been shown to be essential for the production of infectious virions. In this study, we isolated molecules that inhibit viral replication by inhibiting the incorporation of tRNA₃^Lys into virions. The inhibitors of HIV-1 replication described in this work demonstrate that the HIV-1 tRNA packaging step can be exploited for the development of a new family of drugs with novel resistance profiles.