To further determine whether the vRNA levels were regulated by ANP32A, we pre-expressed PB1, PB2 K627E or 627K, PA and NP as well as chANP32A-X1 or huANP32A in 293T cells for 24h before infection with PR8-PB2 K627E or PR8-PB2 627K virus (MOI = 5) and CHX-treatment for 4 h. The gene discussed is ANP32A; the disease is infection.