CPSF6 and HIV-1 infection: Among these cellular proteins, nucleoporins (NUPs) (5, 6), cleavage and polyadenylation specificity factor 6 (CPSF6) (7, 8), as well as the β-karyopherin transportin-SR2 (TRN-SR2; transportin-3) (4, 9, 10), have been proposed to support HIV-1 infection.