Oracle, a novel PDZ-LIM domain protein expressed in heart and skeletal muscle

In order to identify novel genes enriched in adult heart, we performed a su btractive hybridization for genes expressed in mouse heart but not in skele tal muscle. We identified two alternative splicing variants of a novel PDZ- LIM domain protein, which we named Oracle. Both variants contain a PDZ doma in at the amino-terminus and three LIM domains at the carboxy-terminus. Hig hest homology of Oracle was found with the human and rat enigma proteins in the PDZ domain (62 and 61% respectively) and in the LIM domains (60 and 69 %, respectively). By Northern hybridization analysis, we showed that expres sion is highest in adult mouse heart, low in skeletal muscle and undetectab le in other adult mouse tissues. In situ hybridization in mouse embryos con firmed and extended these data by showing high expression of Oracle mRNA in atrial and ventricular rmyocardial cells from E8.5. From E9.5 low expressi on of Oracle mRNA was detectable in myotomes. These data suggest a role for Oracle in the early development and function of heart and skeletal muscle. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.