Albumin (ALB) is a serum protein synthesized in the liver and is an important index of some diseases.However,the role of the upstream promoter region in regulating transcription has not been established in avian genomes.In the present study,we established a model for assessing duck ALB (duALB) promoter activity in different cell lines by construction of a duALB promoter-driven GFP-expressing vector,which exhibited high expression activity in liver-derived cells,such as the chicken embryo liver cell line (CEL) and the rat liver cell line (BRL-3A) ,and much lower expression in a chicken fibroblast cell line (DF-1) and mouse spermatogonial cell line (GC-1) .To further understand the mechanisms of duALB transcription,we employed bioinformatics methods to identify potential cis-regulatory elements in the duALB promoter.Using the firefly luciferase reporter gene driven by a series of constructs carrying progressive deletions of the duALB promoter,the core transcriptional regulatory region was identified to be located in the -190/-51 bp region.This region contained 3 potential transcription factor binding sites,1 each for hepatocyte nuclear factor (HNF-3β) (-158/-149) ,CCAAT/Enhancer binding protein element (C/EBPα) (-119/-107) ,and HNF-1 (-67/-57) .Site-directed mutagenesis of HNF-1 and C/EBPα binding sites resulted in a significant reduction in duALB promoter activity.Two potential cis-regulatory elements (C/EBPα and HNF-1) were responsible for its transcriptional activity in liver-derived cells.Because the liver-specific expression of duALB is functionally conserved in avian species,our findings contribute to the understanding of the fundamental mechanisms of ALB regulation in birds.