ANP32B and infection: To investigate the consequence of absence of ANP32A or ANP32B proteins on infectious IAV replication in human cells, control, single-knockout, and double-knockout cells were infected at a multiplicity of infection (MOI) of 0.005 with three different viruses whose genetic content corresponded to the polymerase constellations tested in Fig. 1 and 2, i.e., from Vic/75, Tky/50-92 (E627K), or Eng195.