Abstract
Fatty acid binding protein 4 (FABP4) was crucial to fatty acid uptake and intracellular transport. However, the mechanisms regulating yak (Bos grunniens) FABP4 transcription were not determined. In the current study, predominant expression levels of yak FABP4 were identified in subcutaneous fat and longissimus dorsi muscles by quantitative real-time polymerase chain reactions (qPCR). The CCAAT/enhancer binding protein alpha (CEBP alpha) and myocyte enhancer factor 2A (MEF2A), as transcriptional activator or repressor in the promoter region of FABP4, were confirmed by both site-directed mutagenesis experiment and chromatin immunoprecipitation assay. Additionally, molecular mechanisms of CEBPalpha regulation were analyzed to explore the transcriptional regulatory property of FABP4, which indicated that transcriptional activity of CEBPalpha depended on CCAAT/ enhancer binding protein beta (CEBP beta) transcription factor. Our results demonstrated that CEBP beta binding directly to the promoter region drove CEBPalpha transcription, improving yak FABP4 transcriptional activity in adipocytes. This mechanism expanded the information on the transcriptional regulatory network of adipogenesis.