Figure 1.
(A) Schematic representation of the SARS‐CoV N protein, showing the SUMO‐1 conjugation site (K62), three putative nucleolar localization signals, the S/R‐rich motif, the RNA‐binding domain and self‐association domain. (B) Analysis of the expression of N protein in bacterial and mammalian cells. Plasmids pGEX‐5X‐1 and pGEX‐N were transformed into E. coli BL21, and expressed by induction with IPTG. The GST (lane 1) and GST‐N (lane 2) proteins were affinity‐purified and separated on an SDS–10% polyacrylamide gel. The protein was visualized by staining the gel with Coomassie blue. Total cell lysates prepared from HeLa cells transfected with pKT0‐Flag empty plasmid (lane 3) and Flag‐tagged N protein (lane 4) were separated by SDS–PAGE and analyzed by Western blotting with anti‐Flag antibody. Numbers on the left and right indicate molecular masses in kilodaltons.