ATG5 and infection: Since the results so far raised the possibility that MERS-CoV may benefit from reducing autophagy, we generated VeroB4 cells with a knockout of the pivotal autophagy gene ATG5. Compared to WT cells, infection of VeroB4 Atg5-KO cells led to the formation of 52-fold more infectious viral particles (Fig. 7a) while genomic viral RNA copies only increased by 6-fold (Fig. 7b).