Molecular cloning, characterization and expression analysis of C/EBP α, β and δ in adipose-related tissues and adipocyte of duck (Anas platyrhynchos)

CCAAT/enhancer binding protein alpha, beta, delta (C/EBP alpha, beta, delta) are essential transcriptional factors in regulating adipose development. However, information about their sequence characteristics and functions during adipocyte development still remains scarce in birds. In present study, we found that duck C/EBP alpha, beta, delta differed in their phosphorylation sites and low complexity regions (LCRs) among their orthologs and paralogs. Phylogenetic analysis showed that C/EBP alpha, beta, delta had different evolutionary patterns, and each of duck C/EBP alpha, beta, delta was strikingly diverged from orthologs of other Ayes. Results of quantitative real-time PCR exhibited that C/EBP alpha, beta, delta were all highly expressed in duck adipose tissues. Indeed, investigations of changes in both their mRNA levels and lipid droplet content during duck adipocytes differentiation showed that their expression profiles were closely related to cellular lipid accumulation. Furthermore, hierarchical clustering analysis of the C/EBPs and lipid metabolism-related genes expression profiles showed that C/EBP alpha was clustered with genes related to lipolysis, lipogenesis and fatty acid desaturation, whereas C/EBP beta, delta were clustered with genes related to de novo lipogenesis and fatty acid elongation, which were different from mammals. In summary, C/EBP alpha, beta, delta of duck differ from other species in their structures and have different effects on lipid metabolism during adipocytes differentiation. This research serve as a foundation for further investigations about avian C/EBP alpha, beta, delta in adipocytes differentiation and adipose development.