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Porcine insulin receptor substrate 4 (IRS4) gene: cloning, polymorphism and association study

Masopust, Martin, Vykoukalová, Zuzana, Knoll, Aleš, Bartenschlager, Heinz, Mileham, Alan, Deeb, Nader, Rohrer, Gary A., Čepica, Stanislav
Molecular Biology Reports 2011 v.38 no.4 pp. 2611
Large White, Meishan, X chromosome, alleles, backfat, chromosome mapping, phosphorylation, polymerase chain reaction, promoter regions, quantitative trait loci, single nucleotide polymorphism, swine, tyrosine
Using PCR and inverse PCR techniques we obtained a 4,498 bp nucleotide sequence FN424076 encompassing the complete coding sequence of the porcine insulin receptor substrate 4 (IRS4) gene and its proximal promoter. The 1,269 amino acid porcine protein deduced from the nucleotide sequence shares 92% identity with the human IRS4 and possesses the same domains and the same number of tyrosine phosphorylation motifs as the human protein. We detected substitution FN424076:g.96C<G in the promoter region that segregates in Meishan and a synonymous substitution FN424076:g.1829T<C in the coding sequence with allele C present only in Meishan. Linkage mapping placed the IRS4 gene at position 82 cM on the current USDA-USMARC linkage map of porcine chromosome X. Association analyses were performed on 555 animals of 12th-15th generation of the Meishan × Large White cross and showed that both SNPs were highly significantly associated with backfat depth (P = 0.0005) and that the SNP FN424076:g1829T<C was also associated with loin depth (P = 0.017). The Meishan alleles increased back fat depth and decreased loin depth. IRS4 can be considered a positional candidate gene for at least some of the QTL located at the centromeric region of porcine chromosome X.