Differential expression and tissue distribution of parkin isoforms during mouse development

Mutations of the park-in gene are a cause of autosomal recessive juvenile p arkinsonism. Although the parkin gene has been isolated from mouse, rat, an d human, little is known about its expression in neural and nonneural tissu es during development. In this study, we used a polyclonal antibody to a pe ptide downstream of the park-in ubiquitin domain to investigate (1) the dif ferential expression of parkin isoforms in protein extracts from fetal and adult mouse tissues, and (2) the distribution of parkin in mouse fetal tiss ues at different developmental stages and in adult CNS tissues. By Western blot analyses, at least three isoforms of parkin of 22, 50, and 55 kDa were differentially expressed in mouse tissues. The p22 and p50 isoforms were f ound in fetal and adult mouse CNS tissues, while the p55 isoform was found only in adult tissues. The p50 isoform is the predominant form in both feta l and adult tissues. Immunolocalization in mouse fetuses showed that parkin was expressed only after neuronal differentiation. Although parkin was loc alized throughout the cytoplasm, the highest level of parkin was found in t he neurites of both fetal and adult neurons. (C) 2001 Elsevier Science B.V. All rights reserved.