FIG 5 .
Cleavage of MERS-CoV nsp3/nsp4 junction is essential for DMV formation. (A) 293T cells were transfected with indicated plasmids and analyzed using Western blotting. nsp3 was detected with anti-SARS-nsp3 serum, and nsp4 was detected with anti-V5 monoclonal antibody. (B to E) HuH-7 cells were transfected with mutant nsp3-4 constructs individually (B and C) or cotransfected with the PLpro domain of nsp3 (D and E) and analyzed using EM. Red arrows point at zippered ER, and in panel E, some putative DMVs are indicated with red asterisks. N, nucleus; M, mitochondria; LD, lipid droplet. Bars, 500 nm.