Identification, expression and variation of theGNPDA2gene, and its association with body weight and fatness traits in chicken

Abstract

Background.TheGNPDA2(glucosamine-6-phosphate deaminase 2) gene is a member ofGlucosamine-6-phosphate (GlcN6P) deaminase subfamily, which encoded an allosteric enzyme of GlcN6P. Genome-wide association studies (GWAS) have shown that variations of humanGNPDA2are associated with body mass index and obesity risk, but its function and metabolic implications remain to be elucidated.The object of this study was to characterize the gene structure, expression, and biological functions ofGNPDA2in chickens.Methods.Variant transcripts of chickenGNPDA2and their expression were investigated using rapid amplification of cDNA ends (RACE) system and real-time quantitative PCR technology. We detected theGNPDA2expression in hypothalamic, adipose, and liver tissue of Xinghua chickens with fasting and high-glucose-fat diet treatments, and performed association analysis of variations ofGNPDA2with productive traits in chicken. The function ofGNPDA2was further studied by overexpression and small interfering RNA (siRNA) methods in chicken preadipocytes.Results.Four chickenGNPDA2transcripts (cGNPDA2-a∼cGNPDA2-d) were identified in this study. The complete transcriptGNPDA2-a was predominantly expressed in adipose tissue (subcutaneous fat and abdominal fat), hypothalamus, and duodenum. In fasting chickens, the mRNA level ofGNPDA2was decreased by 58.8% (P< 0.05) in hypothalamus, and returned to normal level after refeeding. Chicken fed a high-glucose-fat diet increasedGNPDA2gene expression about 2-fold higher in adipose tissue (P< 0.05) than that in the control (fed a basal diet), but decreased its expression in hypothalamus. Two single-nucleotide polymorphisms of theGNPDA2gene were significantly associated with body weight and a number of fatness traits in chicken (P< 0.05).Conclusion.Our findings indicated that theGNPDA2gene has a potential roles in the regulation of body weight, fat and energy metabolism in chickens.