THE GABA-A RECEPTOR BETA-3 SUBUNIT GENE - CHARACTERIZATION OF A HUMAN CDNA FROM CHROMOSOME 15Q11Q13 AND MAPPING TO A REGION OF CONSERVED SYNTENY ON MOUSE CHROMOSOME-7

A cDNA encoding the human GABAA receptor β3 subunit has been isolated from a brain cDNA library and its nucleotide sequence has been determined. This gene, GABRB3, has recently been mapped to human chromosome 15q11q13, the region deleted in Angelman and Prader-Willi syndromes. The association of distinct phenotypes with maternal versus paternal deletions of this region suggests that one or more genes in this region show parental-origin-dependent expression (genetic imprinting). Comparison of the inferred human β3 subunit amino acid sequence with β3 subunit sequences from rat, cow, and chicken shows a very high degree of evolutionary conservation. We have used this cDNA to map the mouse β3 subunit gene, Gabrb-3, in recombinant inbred strains. The gene is located on mouse chromosome 7, very closely linked to Xmv-33 between Tam-1 and Mtv-1, where two other genes from human 15q11q13 have also been mapped. This provides further evidence for a region of conserved synteny between human chromosome 15q11q13 and mouse chromosome 7. Proximal and distal regions of mouse chromosome 7 show genetic imprinting effects; however, the region of homology with human chromosome 15q11q13 has not yet been associated with these effects. © 1991.