Genetic Variations Analysis and Characterization of the Fifth Intron of Porcine NRAMP1 Gene

X M Yan,J W Ma,J Ren,J Gao,Y M Guo,L S Huang,N S Ding,Q L Shu,H S Ai,C Y Chen

doi:10.5713/ajas.2004.1183

Abstract

The natural resistance-associated macrophage protein 1 (NRAMP1) gene was identified as a candidate gene controlling the resistance and susceptibility to a number of intracellular parasites in pigs. The genetic variations in a 1.6 kb region spanning exon 1 and exon 3 of the porcine NRAMP1 gene were investigated by PCR-HinfI-RFLP in samples of 1347 individuals from 21 Chinese indigenous pig populations and 3 western pig breeds. Three alleles (A, B, C) and four genotypes (AA, BB, AB, BC) were detected. Significant differences in genotype and allele frequencies were observed between Chinese indigenous pig populations and exotic pig breeds, while in general the differences in genotype and allele frequencies among Chinese indigenous pig populations were not significant. The allele C was detected only in Duroc, Leping Spotted and Dongxiang Spotted pig, and the two Chinese pig populations showed similar genotype and allele frequencies. Four Chinese Tibetan pig populations displayed genetic differentiation at the NRAMP1 gene locus. In addition, intron 5 of the NRAMP1 gene was isolated and characterized by directly sequencing the PCR products encompassing intron 5. The alignment of intron 5 of the porcine, human, equine and ovine NRAMP1 gene showed a similarity of 45.38% between pig and human, 52.55% between pig and horse, 63.47% between pig and sheep, respectively. (Asian-Aust. J. Anim. Sci. 2004. Vol 17, No. 9 : 1183-1187)

Highlights

The natural resistance-associated macrophage protein 1(Nramp1), the macrophage specific protein encoded by the NRAMP1 gene, acts in the early preimmune phase of infection
The NRAMP1 gene was identified as a candidate gene controlling the resistance and susceptibility to a number of intracellular parasites such as Salmonella (Sun et al, 1998; Bellamy, 1999)
The objective of the present study is to detect genetic variations at the NRAMP1 locus in Chinese indigenous pig populations and exotic pig breeds by PCRRFLP, and to isolate intron 5 of the NRAMP1 gene in order to study the breed characteristics of Chinese indigenous pig breeds and to take advantage of the valuable genetic resource of Chinese indigenous pigs for pig breeding

Summary

Introduction

(Nramp1), the macrophage specific protein encoded by the NRAMP1 gene, acts in the early preimmune phase of infection. NRAMP1 induces lysosomes to fuse with the bacterial phagosome, eventually leading to a mature, acidified and fully bactericidal phagolysosome. The hydrolase hydrolyses pathogens in the phagolysosome. The NRAMP1 protein is a divalent-metal transporter and completes for the acquisition of essential divalent metals from the phagolysosome lumen, resulting in pathogen death for lack of ions and decompensation (Vidal, et al, 1993; Malo et al, 1994; Blackwell et al, 2000; Forbes et al, 2001). The NRAMP1 gene was identified as a candidate gene controlling the resistance and susceptibility to a number of intracellular parasites such as Salmonella (Sun et al, 1998; Bellamy, 1999).

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