Transcriptional control of CCAAT/enhancer binding protein zeta gene in chicken adipose tissue

CCAAT/enhancer binding protein zeta (C/EBPZ) was differentially expressed in abdominal adipose tissues of fat and lean broilers and regulated adipogenesis in chicken. The objective of this study was to elucidate the transcriptional regulation of C/EBPZ gene in chicken adipose tissue. A 2031-base pair (bp) chicken C/EBPZ sequence (2025 nucleotides upstream to 6 nucleotides downstream from the initiator codon, -2025/+6) was studied. The sequence exhibited a significant promoter activity (P <0.05) and had some cis-acting elements, notably, a core promoter was identified in nucleotides −94 to +6. Additionally, DNA pull-down assay showed that proteins interacted with chicken C/EBPZ promoter (−173/+6) in preadipocytes were implicated in transcription, post-transcriptional regulation and translation. In addition, KLF2 facilitated the activities of chicken C/EBPZ promoter (−2025/+6, −1409/+6, −793/+6, −485/+6, −173/+6, and −94/+6) in preadipocytes (P <0.05). The expression levels of KLF2 and C/EBPZ in chicken abdominal adipose tissue were substantially associated (r=0.5978278, P <0.0001), and KLF2 increased C/EBPZ expression in vitro (P <0.05). Additionally, chromatin immunoprecipitation (ChIP)-PCR analysis revealed that KLF2 has the ability to interact with the chicken C/EBPZ promoter regions at least at the positions −1245/−1048 and −571/−397. Mutation analysis showed that the CGCAGCGCCCG motif located in the chicken C/EBPZ promoter at positions -45 to -35 is involved in regulating transcription and facilitates trans activation by KLF2. These results provided some information of transcription control of C/EBPZ in chicken adipose tissue.