Nucleotide variants of the Nramp1 gene in pigs and their effects on disease resistance

Abstract

The Nramp1 gene is an important factor associated with susceptibility to infectious diseases caused by intracellular pathogens. The objective of this study was to determine the structures and sequences of Nramp1 in Tibetan, Gansu Black, Large White, Yorkshire, and Duroc pigs. Sequence analysis of the Nramp1 gene in the five pig breeds revealed the presence of 11 nucleotide variants in intronic regions, 2 nucleotide variants in the control region, 10 nucleotide variants and one deletion in the 3’ non-coding region, and 15 nucleotide variants in the exons. However, only 4 nucleotide variants resulted in amino acid changes. Further analysis predicted that the Tibetan pig Nramp1 protein harbors 10 transmembrane domains. The analysis also predicted 10 serine phosphorylation sites, 3 threonine phosphorylation sites, and 4 tyrosine phosphorylation sites in the Nramp1 protein of Tibetan pigs. Predictions of the Tibetan pig Nramp1 tertiary structure revealed 7 putative a -helices and 5 putative b-sheets. Predictions of the Yorkshire pig Nramp1 protein revealed significant differences compared with the Tibetan pig Nramp1 protein. The results indicated that differences in transmembrane domains and tertiary structures of the Nramp1 protein of the Tibetan and Yorkshire pig breeds could explain differences in the disease resistance of these two breeds