Structure and linkage of the D2 dopamine receptor and neural cell adhesion molecule genes on human chromosome 11q23.

The gene encoding the D2 dopamine receptor (DRD2) is located on human chromosome 11q23 and has been circumstantially associated with a number of human disorders including Parkinson's disease, schizophrenia, and susceptibility to alcoholism. To determine the physical structure of the DRD2 gene, we utilized cosmid cloning, isolation of yeast artificial chromosomes (YACs), and pulsed-field gel electrophoresis to construct a long-range physical map of human chromosome 11q23 linking the genes for the DRD2 and neural cell adhesion molecule (NCAM). The D2 dopamine receptor gene extends over 270 kb and includes an intron of approximately 250 kb separating the putative first exon from the exons encoding the receptor protein. The resulting physical map spans more than 1.5 mb of chromosome band 11q23 and links the DRD2 gene with the gene encoding the NCAM located 150 kb 3' of the DRD2 gene and transcribed from the same DNA strand. We additionally located the sites of at least four hypomethylated HTF islands within the physical map, which potentially indicate the sites of additional genes. High-resolution fluorescent in situ suppression hybridization using cosmid and YAC clones localized this gene cluster between the ApoAI and STMY loci at the interface of bands 11q22.3 and 11q23.1.