Possible mechanisms of the accumulation of phosphorylated eIF2a in ActD-treated, rMP12-rLucinfected cells ActD treatment of uninfected cells resulted in a significant reduction of the polysome fraction, but it did not abolish the translational activities ( Figure S1 ). rMP12-rLuc replication in the cells treated with ActD or a-amanitin promoted the accumulation of the phosphorylated eIF2a, resulting in translational suppression of viral proteins (Figure 4) . The increased amounts of phosphorylated eIF2a clearly correlated with the concentration of ActD or a-amanitin in rMP12-rLuc-infected cells ( Figure S2 ). In contrast, rMP12-rLuc replication in the absence of transcriptional suppressor induced only low levels of eIF2a phosphorylation (Figure 4 ). Yet, the phosphorylation of PKR occurred in cells supporting the replication of RVFV lacking NSs both in the absence and presence of ActD ( Figure 6D ). Thus, a significant accumulation of phosphorylated eIF2a occurred only in cells in which replication of RVFV lacking NSs was combined with the treatment with transcriptional inhibitors.