Fig. 4
A short, conserved motif within SARS-CoV-2 NSP2 is required for processing of the NSP1/NSP2 junction by the PLpro (NSP3). Cell lysates from BHK cells infected with vTF7-315 and transfected with plasmids that express the SARS-CoV-2 NSP1-NSP2-Flag (wt or with a small deletion, removing the conserved motif) either alone (odd numbered lanes) or with the plasmid encoding the SARS-CoV-2 PLpro (even numbered lanes) were analyzed by immunoblotting using rabbit anti-Flag antibodies, followed by anti-rabbit HRP-conjugated secondary antibodies and a chemiluminescence detection kit. Molecular mass markers (kDa) are indicated on the left. A negative control (no DNA) was included (lane 5). The uncut membrane is shown in Supplementary Fig. S1. This experiment has been repeated three times in total with separate transfections and western blots and resulted in very similar results. The additional two experiments are shown in Supplementary Figs. S2 and S3. Band intensities for each experiment were quantified using pixel count in ImageJ. Each lane was set to 100%, and the relative percentage of each of the two bands was calculated. The mean values of the triplicates were plotted, and the bar diagram with error bars representing the standard deviation (SD) are shown on the right side of the figure.
