Genomic organization and promoter analysis of the bovine ADAM12 gene

A disintegrin and metalloprotease (ADAM) 12 is a member of the ADAM family possessing a putative role in a variety of biological processes such as modulation of proteolytic processing, cell adhesion, cell fusion, and signaling. Recently, it has been suggested that ADAM12 is involved in regulation of adipogenesis as well as myogenesis. In this study, we have determined the genomic structure of 5'- and 3'-regions in the bovine ADAM12 gene. We could obtain characteristics of lower homology of its exon 2 with human counterpart. Human exon S19 encodes for the sequence specific to a shorter secreted form of ADAM12S. The bovine ADAM12 gene had no canonical 3'-splice acceptor site at 5'-side of the putative exon S19, suggesting that the cattle could not produce a ADAM12S counterpart. To identify the regulatory elements, a 12 kb 5'-flanking region of the gene was cloned and luciferase reporter assay was carried out. Reporter plasmids with different length of proximal promoter region indicated the similar patterns of promoter activities between 3T3-L1 preadipose and Cos-1 nonadipose cells. However, 2.0 and 0.2 kb fragments located at - 8 and - 4.5 kb upstream of the putative transcription start site, respectively, increased the ADAM12 promoter activity about 1.5- to 2-fold in 3T3-L1, but not in Cos-1. These results suggested that the two distal regions might contribute to the preadipocyte-specific expression of ADAM12 gene.