Regional and cellular localisation of Parkin co-regulated gene in developing and adult mouse brain.

Parkin Co-Regulated Gene (PACRG) is a novel gene that is oriented in a head-to-head array with parkin, and expression of the two genes is regulated by a shared bi-directional promoter. Mutations in parkin are the most common cause of early-onset autosomal recessive Parkinson's disease, however the function of PACRG and potential role in the pathogenesis of Parkinson's disease are unclear. We generated polyclonal anti-PACRG antisera and performed immunohistochemical analysis of the regional and temporal distribution of Pacrg in the mouse brain. The protein was heterogeneously expressed in neurons throughout the mouse brain, with highest levels observed in the rhombencephalon and mesencephalon. Expression was detectable at 1 week of age, increased to maximal levels by 4 weeks and subsequently declined after 3 months. Comparison of parkin and Pacrg immunohistochemistry demonstrated a correlation of both staining distribution and intensity for the two proteins. These results suggest that the transcriptional co-regulation of Pacrg and parkin leads to a similar regional protein distribution in mouse brain, which may have functional significance for the two proteins.