CPSF6 and HIV-1 infection: To investigate the role played by HIV-1 infection–induced CPSF5 and CPSF6 translocation in infection-induced changes in APA, we infected A549 cells with HIV-1 bearing the capsid mutation N74D (HIV-1-N74D) or A77V (HIV-1-A77V), which fail to induce CPSF5 and CPSF6 translocation to nuclear speckles (2, 4).