Fig. 4.

Deletion mapping of the N-protein reveals regions critical for human coronavirus packaging sequence binding.

(A–F) Our in vivo cell-based assay was performed with various truncated forms of N-protein with the human coronavirus packaging signal sequence. Results of the ONPG and CRPG assays are shown on the right, and all experiments were formed in triplicates. Data are presented as the mean ± SD (standard deviation) of three separate experiments. (G) Assay for LacZ translation on X-gal/IPTG agar plates upon co-transformation of JM109 cells with SARS-CoV N-deletion mutants and CoV packaging sequences (MHV-PS97 and hCoV-PS100). Minus (-) show JM109 transformants in the absence and presence of N-protein and packaging sequence, respectively. All experiments were performed three times.