In this study, we applied bacterial artificial chromosome (BAC) technology with PRVΔTK/gE/gI as the base material to replace first, central, and terminal segments of US3 gene codon-deoptimized fragments via two-step Red-mediated recombination in E. coli GS1783 cells. The three constructed BACs were co-transfected gI part gE carrying homologous sequences (gI+gE’), respectively, swine testicular ...