Interestingly, depletion of Cul3 in HEK293T cells did not alter infection with the HIV-1 ∆NF-κB/NFAT I, II mutant, suggesting that the NF-κB/NFAT binding sites in the LTR are crucial for the Cul3-mediated reduction of viral gene expression (Figure 5b). Here, NFKB1 is linked to infection.