HIV-1 Infection Regulates Gene Expression by Altering Alternative Polyadenylation Through CPSF6 and CPSF5 Delocalization.

HIV-1 viral core transport to the nucleus, an early infection event, triggers cleavage and polyadenylation specificity factor (CPSF)5 and CPSF6 to translocate from paraspeckles to nuclear speckles, forming puncta-like structures. CPSF5 and CPSF6 regulate alternative polyadenylation (APA), which governs approximately 70% of gene expression. APA alters the lengths of mRNA 3'-untranslated regions (3'-UTRs), which contain regulatory signals influencing RNA stability, localization, and function. We investigated whether HIV-1 infection-induced changes in CPSF5 and CPSF6 subcellular localization are accompanied by changes in cellular function. Using two independent methodologies to assess APA in human primary CD4+ T cells and cell lines, we found that HIV-1 infection regulates APA, dependent on the interaction of CPSF6 with the viral capsid, recapitulating the APA phenotype observed in CPSF6 knockout cells. Our study demonstrates that HIV-1 infection leverages the interaction between the viral capsid and CPSF6 to co-opt cellular processes, alter gene expression, and drive pathogenesis.