Role of biomolecular condensates in regulating HIV-1 viral ribonucleoprotein complex formation in the setting of substance use disorder

HIV-1/AIDS is a devastating immunodeficiency disease that has resulted in over 35 million deathsacross the globe. There is a compelling ongoing need to develop novel treatment strategies to combat thecontinuing emergence of drug-resistant viral strains. A drug target that has not yet been successfully brought tothe clinic is the interaction of the Gag protein with its RNA genome to form the viral ribonucleoprotein complex,which initiates the process of virion assembly. A deeper understanding of the biochemical and biophysicalinteractions that drive viral ribonucleoprotein complex formation is needed to advance further therapeuticdevelopment. Based on recent findings that viral ribonucleoprotein complexes undergo liquid-liquid phaseseparation to form biomolecular condensates, this proposal explores the molecular underpinnings of Gag-viralRNA interactions. We have assembled an accomplished interdisciplinary team of scientists to work at thecrossroads of retrovirology, RNA biology, biophysics, and pharmacology to shed light on our understanding ofviral and cellular biomolecular condensates in HIV-1 infection. Our preliminary results suggesting that HIV-1 ribonucleoprotein complexes form in the nucleus inspiredthis provocative proposal to investigate the interplay of virus replication machinery with nuclear bodies thatform biomolecular condensates. In the R21 phase, we will use innovative methods involving biophysics,genetics, state-of-the-art live cell imaging, and targeted pharmacological interventions to examine whetherHIV-1 ribonucleoprotein complexes assemble into biomolecular condensates in the nucleus. In the R33 phase,we will extend these studies to probe mechanistic questions focusing on whether nuclear BMCs play criticalroles in regulating HIV-1 transcription, latency reactivation, and genomic RNA packaging. Due to the highincidence of substance use disorder in people with HIV-1/AIDS, we will also investigate whether drugs ofabuse influence HIV-1 nuclear biomolecular condensates. Elucidating the genetic determinants of HIV-1condensate formation could lead to the identification of novel drug targets to treat HIV/AIDS.