Construction and expression of Mx1 transgenic vector. (A) Comparison of 2 alleles of Mx1 gene in Tibet miniature pigs (position 1675–1718 in nucleic acid sequence). The 3 base pair (bp)-deleted sequence is indicated with a dashed line. (B) Schematic diagram of the transgenic vector pMx1-2A-EGFP and the binding sites of primers used in genomic PCR assays to screen for the presence of the transgene are marked with arrows. The size of the PCR product using primers Mx1-2 and Mx1-7 is 192 bp. The same primers generate a PCR fragment of 575 bp from the endogenous genomic Mx1 due to the existence of an intron. The primer Mx1-5 is located in the 2A sequence and the transgenic vector produces a 750 bp DNA fragment when amplified by PCR using primers Mx1-1 and Mx1-5. These primers cannot amplify wild-type genomic DNA. (C) Schematic diagram of the Mx1 expression vector pVAX-Mx1. (D) Transient expression of pMx1-2A-EGFP and pVAX-Mx1 in 293 T cell. The arrowhead indicates the uncleaved transgenic Mx1-2A-EGFP protein. Arrow indicates the cleaved Mx1 protein.