Differential expression of the parkin gene in the human brain and peripheral leukocytes

Abstract

Molecular cloning of the responsible gene on chromosome 6q25.2-27 for autosomal recessive juvenile parkinsonism (AR-JP) identified a novel protein of unknown function, named parkin. In patients with AR-JP, deletions most commonly involve exons 3–5 in the parkin gene. For mutation screening we tried to analyze the parkin transcript amplified by RT-PCR. Based on the assumption that illegitimate transcription of the parkin gene may occur in every cell type, we successfully amplified the parkin message from human peripheral leukocytes using RT-PCR. The parkin transcript in leukocytes was smaller in size than the full-length transcript in the brain. DNA sequencing determined that exons 3–5 were spliced out in the normal human leukocyte transcript. Our results demonstrate that alternative splicing produces distinct parkin transcripts in different tissues. Moreover, physiological splicing of deletion-prone exons may provide an important clue to understanding the pathogenesis of AR-JP.