We have previously reported that an optimal in vitro infection by influenza A virus (IAV) requires three components of Cullin 4-RING E3 ubiquitin ligases (CRL4) complexes, namely the DDB1 adaptor and two substrate recognition factors, DCAF11 and DCAF12L1, which mediate non-degradative poly-ubiquitination of the PB2 subunit of the viral polymerase. Here, DDB1 is linked to infection.