Abstract：This study aims to obtain the transcription regulatory region of Nramp1 gene which is tissue-specifically expressed in porcine pulmonary alveolar macrophages. The study identified the transcription start site of pig(Sus scrofa) Nramp1 gene using 5'-RACE. Eight expression vectors, pLUC1430, pLUC1136, pLUC840, pLUC751, pLUC487, pLUC379, pLUC274 and pLUC179, with serial deleted upstream fragments were constructed by cloning different deletion fragments of －1 327 bp to ＋86 bp region into pGL3-Basic vector, respectively. The expression vectors were co-transfected with Renilla luciferase vector into porcine pulmonary alveolar macrophages, kidney cells, preadipocytes and fetal fibroblast cells, respectively. Expression activities were analyzed using dual luciferase reporter system for different fragments in order to identify the core regulatory region. Our result showed the core regulatory region of Nramp1 gene ranged from －386 bp to －173 bp. The transcripion activities of pLUC487[－386~＋86] region were further compared among porcine pulmonary alveolar macrophages, kidney cells, preadipocytes and fetal fibroblast cells, in which Nramp1 promoter exhibited significantly higher activity in porcine pulmonary alveolar macrophages(P<0.01). We confered that Nramp1 promoter was specifically expressed in porcine alveolar macrophages. Our study gained a transcription regulatory element specifically expressed in pulmonary alveolar macrophages, which facilitates the tissue-specific expression of foreign genes in porcine pulmonary alveolar macrophages.
