Characterization of chicken natural resistance-associated macrophage protein encoding genes (Nramp1 and Nramp2) and association with salmonellosis resistance.

Natural resistance-associated macrophage protein 1 and 2 encoding genes (Nramp1 and Nramp2) are related to many diseases. We cloned the cDNA of chicken Nramp1 and Nramp2 genes, characterized their expression and polymorphisms, and investigated the association of some SNPs with resistance to salmonellosis. The Nramp1 cDNA was 1746 bp long and the Nramp2 cDNA was 1938 bp long. These cDNAs are similar to previously reported cDNAs, varying by two and one amino acids, respectively. The chicken Nramp1 gene expressed predominantly in liver, thymus and spleen in both females and males. The Nramp2 gene expressed in almost all tissues, but predominantly in breast muscle, leg muscle, cerebrum, cerebellum, lung, kidney, and heart in both females and males. We identified 45 SNPs and 2 indels in the chicken Nramp1 gene; three of 13 SNPs in the exons were missense mutations (Arg223Gln, Ala273Glu and Arg497Gln). Association analysis indicated that A24101991G is significantly associated with chicken salmonellosis resistance. These results will be useful for functional investigation of chicken Nramp1 and Nramp2 genes.