APOBEC1 and infection: No significant change was observed with the expression of ADAR1–3, APOBEC1, APOBEC2, and APOBEC3A 3D, 3G, and 3H, whereas APOBEC3B, and 3C had a significant decrease, and APOBEC3F had a significant increase in A549 cells during the course of infection with H7N9 (Fig. 5).