Functional analysis of bovine Nramp1 and production of transgenic cloned embryosin vitro

Abstract

SummaryNatural resistance-associated macrophage protein 1 (Nramp1) plays an important role in restraining the growth of intracellular pathogens within macrophages. In this study,Nramp1cDNA was cloned from Qinchuan cattle and its anti-bacterial activity was demonstrated as being able to significantly inhibit the growth ofSalmonella abortusovisandBrucella abortusin macrophages. Calf fibroblasts stably transfected with pSP–NRAMP1–HA vector were used to reconstruct bovine embryos by somatic cell nuclear transfer (SCNT). Reconstructed embryos were maturatedin vitroand the blastocyst formation rate (14.0%) was similar to that of control embryos (14.5%). Transgenic blastocysts were transplanted into 43 recipient cattle, of which 14 recipients became pregnant as evidenced by non-return estrus and by rectal palpation. One fetus was aborted after 6½ months of pregnancy and transgene integration was confirmed by semi-quantitative polymerase chain reaction. Together, this study showed that bovine Nramp1 retains biological function against the growth of intracellular bacteria and can be used to reconstruct embryos and produceNramp1transgenic cattle, which may benefit the animal and enhance their ability to prevent attack by intracellular pathogens.