Species difference in ANP32A underlies influenza A virus polymerase host restriction

The host protein ANP32A is shown here to be a species barrier to the function of avian influenza virus polymerase in mammalian cells; the mutation E627K in viral protein PB2, which allows mammalian ANP32 family proteins to support the avian virus polymerase, is known to be associated with increased virulence of avian viruses in mammals.