Figure 4A shows that all the Arf proteins were expressed at high levels in RD cells. EV71 virions were then used to infect (1 MOI) RD cells that overexpressed a single or a pair of Arf proteins. Control cells transfected with the empty vector were also infected. At the time of infection, BFA (100 ng/ml) was added to cell cultures. Total cellular RNA and viral RNA were extracted after 6 hpi. The copy numbers of EV71 RNA were detected by quantitative real-time PCR. Figure 4B shows that BFA substantially inhibited EV71 replication in RD cells. Here, CDKN2A is linked to infection.