Identifying polymorphisms in the Rattus norvegicus D3 dopamine receptor gene and regulatory region

The D₃ dopamine receptor has been implicated in several neuropsychiatric disorders, including schizophrenia, Parkinson's disease and addiction. Sequence variation in the D₃ gene can lead to subtle alteration in receptor structure or gene expression and thus to a different phenotype. In this study we examine the sequence variation in the D₃ gene in 96 rat strains and substrains. Interestingly, the analyses revealed 10 polymorphisms in the 5′flanking region and four polymorphisms in intronic regions of the gene. Moreover, two single nucleotide polymorphisms (SNPs) that result in amino acid changes were found in the last exon of the D₃ gene in the RNU/Mol strain. Additionally, bioinformatic analysis of the 5′flanking region and first intron of the gene revealed putative transcription factor binding sites that are conserved between mouse and human and are affected by the SNPs, possibly resulting in altered regulation of the subsequent transcription factor.