Fig. 1.
Expression of SIV Gag proteins in live rubella vectors. (A) Rubella genome organization and the structural insertion site. The non-structural (blue) and structural (red) genes are controlled by the genomic (Pgen) and strong subgenomic (Psub) promoters, respectively. The structural insertion site is located between the rubella envelope glycoproteins E2 and E1. (B). The Gag inserts were attached to the transmembrane domain of E2 glycoprotein and the E1 signal peptide, which provided membrane anchor and cleavage site. (C). Five Gag inserts of various sizes were derived from the whole Gag polyprotein (1–510 aa), spanning 41–211, 41–364, 136–364, 136–381 and 41–381 amino acids of Gag. The N and C terminal sequences of Gag inserts are shown in Table S1. BC-sGag2 contains 4 T cell epitopes in tandem and was described previously [18]. (D) Stable expression of the SIV Gag proteins was detected by western blot of Vero cell lysates with monoclonal 2F12, which is specific for the carboxyl half of CA protein. Insert expression was stable through passage P5 or P6. Controls include uninfected cell lysates and recombinant SIV p55 Gag protein.