Predominant neuronal expression of the gene responsible for dentatorubral-pallidoluysian atrophy (DRPLA) in rat

Dentatorubral and pallidoluysian atrophy (DRPLA) belongs to a group of trinucleotide diseases in humans associated with an expanded and unstable (CAG) > 49 repeat within a gene of unknown function. Clinically, DRPLA presents with variable combinations of myoclonus, epilepsy, cerebellar ataxia, choreoathetosis and dementia. Hardly anything is known about the physiological function of the DRPLA gene and the pathological mechanisms causing neuronal cell death and leading to these symptoms. To analyze some of these aspects of the DRPLA gene we isolated the complete coding region of the rat DRPLA gene (rdrpla) and investigated its expression in different developmental stages of rodent tissues. The rdrpla gene shows 92% homology in amino acid sequence to the human gene. In rat the length of the (CAG)n repeat is reduced compared to the human (CAG)n block containing 7-34 repeats with an average of 15. Northern blot analysis revealed that in rodents the rdrpla gene is already expressed during embryo development. In addition this transcript is predominantly represented in neuronal tissues throughout all developmental stages investigated.