Single Nucleotide Polymorphism Scanning and Expression of the Pig PPARGC1A Gene in Different Breeds

Peroxisome proliferator-activated receptor gamma coactivator 1-alpha (PPARGC1A) is a candidate gene for lean meat production because it plays a key role in lipid metabolism. In this study, SNPs within the porcine PPARGC1A gene were investigated using PCR-sequencing and PCR-RFLP. Quantitative real-time PCR and Western blot were then used to analyze mRNA and protein expres- sion in longissimus dorsi muscle (LM), liver, and backfat tissues of Dianna small-ear pigs (DSP, n = 6), Tibetan pigs (TP, n = 6), and large white pigs (LW, n = 6). Five novel SNPs (g.-1269A(G in the 5 0 -upstream regulatory region; g.190C(T, g.218C(A and g.234C(A in exon 8; and g.20C(T in intron 10) and three previously identified SNPs (g.417A(T in exon 8; g.56C(A in exon 9; and g.34G(A in intron 9) were found. Of these, only two, g.-1269A(G and g.234C(A, had three different genotypes in the three breeds (DSP, n = 63; TP, n = 51; and LW, n = 52). Expression was highest in LM, modest in the liver, and minimal in backfat. In LM tissue, LW had higher mRNA and protein levels than DSP and TP (P 0.05), and there was a neg- ative correlation between gene expression and intramus- cular fat (IMF) content. LW had numerically higher expression in liver and backfat tissues than DSP and TP, and the differences in protein levels were significant (P 0.05 in liver, P 0.01 in backfat). In conclusion, PPARGC1A may play ak ey role in down-regulating lipid deposition, and the SNPs with differential genotype dis- tribution among the three pig breeds may be related to gene expression and fat deposition.