As E3L gene remains both in VTT and NTV genome, we supposed that E3 protein was limiting the phosphorylation level of eIF2α which resulted in limited differences between VTT and NTV infection, explaining why we observed there were only small differences between the eIF2α phosphorylation levels of NTV and VTT infection in either primary or PKR silenced HeLa cells. Here, EIF2AK2 is linked to infection.