Molecular cloning, gene expression, and identification of a splicing variant of the mouse parkin gene

We have isolated mouse cDNA clones that are homologous to human Parkin gene, which was recently found to be responsible for the pathogenesis of autosomal recessive juvenile parkinsonism (AR-JP). One of these cDNA clones had the 1,392-bp open reading frame encoding a protein of 464 amino acids with presumed molecular weight of 51,615. The amino acid sequence of mouse parkin protein exhibits 83.2% identity to human Parkin protein, including the ubiquitin-like domain at the N-terminus (identity = 89.5%) and the RING finger-like domain at the C-terminus (identity = 90.6%). Two other clones had the 783-bp open reading frame encoding a truncated protein of 261 amino acids without RING finger-like domain. It was proved to be a novel splicing variant by 3'-RACE method. Northern blot analysis revealed that mouse parkin gene is expressed in various tissues including brain, heart, liver, skeletal muscle, kidney, and testis. It is notable that mouse parkin gene expression appears evident in 15th day mouse embryo and increases toward the later stage of development. These mouse parkin cDNA clones will be useful for elucidating the essential physiological function of parkin protein in mammals.