FIG. 7.
Construction and functional analysis of pseudoviruses derived from different CS protein constructs. (A) Schematic presentation of constructs of human SARS-CoV S protein (BJ01-S), bat SL-CoV S (Rp3-S), and different CS proteins. The numbers in the subscripts indicate the amino acid locations of the BJ01-S sequences used to replace the corresponding region of Rp3-S. The open box indicates the location of the RBM. TPA, signal peptide from tissue plasminogen activator; TM, transmembrane domain derived from the fusion protein of Sendai virus. (B) Western blot analysis. S proteins in transfected 293T cells (top) or purified pseudoviruses (middle) were probed with MAb F26G8 (S-MAb); at the bottom is a blot of different pseudoviruses probed with p24 MAb as a control to determine the relative quantity of HIV pseudovirus for each construct. (C) Measurement of pseudovirus infectivity by determining luciferase activity. Cell lysates were prepared 48 h p.i. from HeLa-huACE2 infected with pseudoviruses containing different S proteins as indicated below the bar graph. The error bars indicate standard deviations.