The ATF6 branch of unfolded protein response and apoptosis are activated to promote African swine fever virus infection

Galindo, I; Hernáez, B; Muñoz-Moreno, R; Cuesta-Geijo, M A; Dalmau-Mena, I; Alonso, C

ASFV infection does not result in an attenuation of protein translation. We studied the expression of UPR markers in virus-infected Vero cells. The activation of the PERK pathway results in the phosphorylation of the eIF2a subunit, leading to translation attenuation. 29 PERK also activates the expression of ATF4, a transcription factor, thus leading to the upregulation of the pro-apoptotic genes CHOP and GADD34. 30 GADD34 association with the phosphatase PP1 produces the dephosphorylation of eIF2a. 5 Tunicamycin treatment caused an increase in CHOP expression in Vero cells; however, no induction of CHOP was observed in ASFV-infected cells by western blot (Figure 5a ). ATF4 expression was detected only in infected cells at 48 hpi. GADD34 protein showed an increase in expression from 16 hpi. Taken together, these results indicate that ASFV inhibits CHOP expression and leads to increased eIF2a dephosphorylation in order to restore protein translation.