Characterization of the visfatin gene and its expression pattern and effect on 3T3-L1 adipocyte differentiation in chickens.

Visfatin is a newly identified adipocytokine that plays an important role in the determination of fat traits. In this study, we investigated the characterization of visfatin and the relationship between gene expression and chicken development to provide a theoretical basis for studying visfatin functions. The main results are summarized as follows: The 1482-bp full coding sequence of the visfatin gene of silky fowl was obtained and found to encode 493 amino acids. This gene contains 26 phosphorylation sites and a conserved domain of the NAPRTase family but no signal peptide sequence. It exhibits six functional motifs, including an amidation site. In chickens, visfatin is a highly conserved protein. The highest expression of visfatin was found in breast muscle and the lowest in bone marrow. There was no difference in expression between visceral fat and subcutaneous fat. However, the expression of visfatin in the bone marrow, liver, kidneys, and subcutaneous and visceral fat of broiler chickens was significantly higher than that in silky fowl (P<0.05). Visfatin mRNA levels in the bone marrow decreased with development (P<0.05) but increased in the liver and leg muscle. Visfatin gene expression in the liver, heart and bone marrow did not differ in silky fowl according to sex. A visfatin fusion protein caused a significant increase in the expression of adipocyte differentiation markers (PPARγ, aP2, C/EBPα, and FAS) compared with the control group and a decrease compared with the insulin group. Taken together, the results of the present study contribute to a better understanding of the expression and role of the visfatin gene in chickens.