Characterization of the mouse A3 adenosine receptor gene: Exon/intron organization and promoter activity

In a previous study, we reported the expression of A3 adenosine receptor mR NA in rat vascular smooth muscle cells (VSMC) and demonstrated that its lev els affect the intracellular concentration of cAMP. In the current study, w e isolated the mouse A3 adenosine receptor (A3AR) gene, characterized its s tructure, and defined its promoter activity in VSMC. The mouse A3AR gene fr agment available to us has 3 kb of coding sequences, composed of two exons separated by a single intron, and 2.3 kb of 5' noncoding region. The promot er region lacks "TATA" and "CAAT" boxes, but contains an initiator consensu s sequence. In accordance with Northern blot analysis of A3AR mRNA, transie nt transfection experiments showed that the promoter activity of this fragm ent was significant in VSMC and astrocytes and high in mast cells. The char acterization of the mouse A3 adenosine receptor gene and insight into its p romoter region will allow further studies to determine the physiological im portance of its transcriptional regulation in different tissues. (C) 1999 A cademic Press.