CPSF6 and HIV-1 infection: Compared with wild-type HIV-1 infections, infections with HIV-1-N74D or HIV-1-A77V, which do not induce CPSF5 and CPSF6 translocation to nuclear speckles, resulted in a similar number of 3’UTR lengthening events but a reduced number of 3'UTR shortening events (Fig. 2B and C).