Molecular characterization and expression analysis of the porcine paraoxonase 3 (PON3) gene

The paraoxonase (PON) gene family has 3 members, PON1, PON2 and PON3, which are known to be involved in oxidative stress-associated processes such as dyslipidemia, diabetes and coronary heart disease. Although PON3 is the least studied paraoxonase, recent findings have shown that it can significantly reduce atherosclerotic lesion formation and obesity in PON3 transgenic mice. Here, we describe the isolation and molecular characterization of the cDNA encoding the porcine PON3 gene. We also report the cloning of three porcine PON3 transcript variants resulting from alternate splicing of exons. Our results show that PON3 mRNA and protein are ubiquitously expressed in pig tissues. Moreover, the relative abundance of PON3 mRNA, measured in perirenal and subcutaneous fat tissues, is higher in obese Upton Meishan gilts compared with the leaner Large White and Ham Line gilts. PON3 mRNA levels measured in fat tissues positively correlate with subcutaneous, visceral and total body fat weights. Four single nucleotide polymorphisms (SNP) were identified in the PON3 coding sequence, and among these, an association was found between the c.449G>A polymorphism and the longissimus dorsi depth estimated breeding value (EBV) trait. Knowledge of the structure, distribution and expression profile of the porcine PON3 gene provides insights into its physiological function. Our results provide further support for involvement of PON3 in obesity-related disorders.