Molecular cloning, expression, mapping of interferon regulatory factor 2 (IRF2) gene and its association with immune traits in pigs

Interferon regulatory factor 2 (IRF2) gene is a member of IRF-family and shown to play functionally diverse roles in the regulation of the immune system. In this report, the porcine IRF2 cDNA was cloned and its 14,000 bp genomic DNA structure was also identified. The putative IRF2 protein included 352 amino acids. Alignment analysis of the predicted porcine IRF2 amino acid sequences with their homologies of other species showed high identity (over 93%). Tissues expression of IRF2 mRNA was observed by RT-PCR, the results revealed IRF2 expressed widely in all analyzed tissues except skeletal muscle. Using the radiation hybrid panel, the porcine IRF2 gene was mapped to chromosome 15 and closely linked to microsatellite S0149 (LOD=6.17, 26 cR). A SNP (GU295944:c.1383 G>C) in exon 6 of porcine IRF2 gene was demonstrated by sequencing and PCR-RFLP analysis. The further association analysis indicated that the SNP was significantly associated with level of IL10 (at day 20), IFN-γ (at day 35) and ratio of IFN-γ/IL10 (at day 35) in serum (P<0.05). The results suggested that IRF2 could be served as a promising candidate gene for pig breeding of disease resistance.