Characterization of the fatty acid binding protein 3 (FABP3) promoter and its transcriptional regulation by cAMP response element binding protein 1 (CREB1) in goat mammary epithelial cells

Fatty acid binding protein 3 (FABP3) is involved in signal transduction pathways, and in the uptake and utilization of long-chain fatty acids. However, the transcriptional regulation of <i>FABP3</i> in goat is unclear. In this study, the <i>FABP3</i> 5′ flanking region was amplified from goat (<i>Capra hircus</i>) genomic DNA. Luciferase reporter vectors containing promoter fragments of five different lengths were constructed and transfected into dairy goat mammary epithelial cells. The region of the promoter located between −1801 and −166 bp upstream of the transcription start site (TSS) exhibited the highest luciferase activity, and contained two cAMP response elements (CREs) located at −1632 bp and −189 bp. Interference with <i>CREB1</i> significantly downregulated <i>FABP3</i> promoter activity. In addition, <i>FABP3</i> promoter activity was significantly reduced after mutation of the CRE1 (−1632 bp) and CRE2 (−189 bp) sites. Further analysis indicated that the CRE2 site was essential for the transcriptional activity induced by <i>CREB1</i>. These results demonstrated that CREB1 is involved in the transcriptional regulation of <i>FABP3</i> expression in the goat mammary gland via a direct mechanism, thus revealing a novel signaling pathway involved in fatty acid metabolism in goat.