Fig. 3: Comparison between IAV and ICV replication platforms.

a Overall assembly of IAV and ICV replication platforms composed of FluPolR (blue), FluPolE (green) and ANP32LRR (orange; human ANP32B in the IAV platform; chicken ANP32A in the ICV platform). FluPolA PB2 K627 and its FluPolC equivalent K649 on both FluPolR and FluPolE are highlighted in yellow. b Comparison of the binding of human ANP32BLRR (dark orange) and chicken ANP32ALRR (light orange) to the PA-C domain of IAV (green) and equivalent P3-C of ICV (white). c Sequence alignment of the PA/P3 subunits of different influenza viruses. Influenza C virus (C/Johannesburg/1/1966) has elongated 490–500 and 550–560 loops, compared with influenza A virus, but it lacks a 51–72 loop. d Variation in the PA490–500 and PA550–560 loops between IAV and ICV affects the positioning of ANP32LRR (orange) and PB2627 (dark green) relative to the PA/P3-C domain (light green). The ICV replication platform structure in panels (a, b and d) is based on PDB 6XZR.