Molecular characterization, tissue expression and polymorphisms of buffalo PPARGC1A gene

Abstract

PPARGC1A exerts important functions in activating many nuclear receptors and transcription factors that are related to energy balance. Previous studies have shown that PPARGC1A gene is associated with lactation traits of dairy cattle. However, the functional role of the buffalo PPARGC1A gene is still unknown. In this work, the complete coding sequence (CDS) of buffalo PPARGC1A was isolated and characterized for swamp and river buffalo. The CDS length of PPARGC1A for both types of buffalo was the same, which was composed of 2394 nucleotides and encoded a peptide composed of 797 amino acid residues. This protein belonged to a hydrophilic protein and contained one RRM-PPARGC1A domain (AA 674-764) without a signal peptide or a transmembrane domain. The differential expressions of this gene in 10 buffalo tissues in lactation and nonlactation displayed that the PPARGC1A was highly expressed in the muscle, heart, liver, brain and kidney of both non-lactating and lactating periods, but its expression was significantly different in the muscle, heart, liver, small intestine, mammary gland, rumen, spleen and lung between the two periods. Eight single nucleotide polymorphisms (SNPs) were found in buffalo, in which the c.778C >T, c.1257G>A and c.1311G>A were shared by two types of buffalo with similar allele frequencies, while the c.419C>T, c.759A>G, c.920C>A, c.926G>A and c.1509A>T were only observed in river buffalo. The SNP419, SNP920 and SNP926 were non-synonymous, which led to the amino acid changes of p.Ser140Phe, p.Pro307His and p.Arg309Lys. Seven nucleotide differential sites were identified in the PPARGC1A gene between buffalo and other Bovidae species. Phylogenetic analysis indicated that buffaloes were independently clustered into one branch, but they were closely related to the species of the Bos genus. The results indicate that buffalo PPARGC1A is an inducible transcriptional coactivator involved in regulating carbohydrate and fat metabolism. It can exert a functional role in a variety of buffalo tissues and may participate in milk fat synthesis and development in the mammary gland.