Molecular cloning, functional characterization, tissue expression and polymorphism analysis of buffalo PRDX6 gene

PRDX6 is a bifunctional protein involved in antioxidant regulation and phospholipid metabolism. Previous studies have shown that PRDX6 is involved in some biological pathways and networks related to lactation. The aim of this study was to explore the characteristics, function, tissue expression and variation of buffalo PRDX6 gene. We cloned and characterized the complete coding sequence (CDS) of buffalo PRDX6. The CDS of PRDX6 for swamp and river buffalo is the same, which consists of 675 nucleotides and encodes a protein of 224 amino acids. Buffalo PRDX6 contains one PRX_1cys functional domain (AA 7-222), which is probably related to the regulation of oxidative stress. Multi-tissue differential expression analysis showed that buffalo PRDX6 was highly expressed in the muscle, brain, lung and small intestine during non-lactation and lactation, and there were significant differences in expression in all the tissues except the small intestine between the two periods. It is worth noting that the mRNA abundance of buffalo PRDX6 in non-lactating mammary gland is higher than that in lactating mammary gland. Among the two single nucleotide polymorphisms (SNPs) identified in the CDS in this study, c.261C>T is shared by the two types of buffalo with different allelic frequencies, and c.426T>G is found only in river buffalo. The c.426T>G is non-synonymous, resulting in the amino acid substitution p.Asn142Lys. Only one nucleotide differential site is identified in PRDX6 gene between buffalo and other species of Bovidae. Phylogenetic analysis indicated that buffalo PRDX6 has a closer genetic relationship with that of the species in Bovidae. These results indicate that PRDX6 probably plays a crucial role in the mammary gland of buffalo. This study provides the foundation for further functional studies of PRDX6 in buffalo.