Non-transfected (–) and transfected (+) 293T whole cell extracts (30 μg) were separated by 12% SDS-PAGE, and the membrane was blotted with MERS-CoV M protein antibody (GTX134866) diluted at 1:1000. The HRP-conjugated anti-rabbit IgG antibody (GTX213110-01) was used to detect the primary antibody.