Genetic mapping of three GABAA receptor-subunit genes in the mouse.

GABAA receptors are a heterogeneous group of heterooligomeric ligand-gated anion channels that represent the main means of synaptic inhibition in neuronal tissue. At least 14 distinct GABAA subunit proteins representing 5 different classes have been identified. Using rat brain cDNAs for the GABAA receptor beta 1-, alpha 2-, and alpha 4-subunits, we have assigned the corresponding murine genes Gabrb-1, Gabra-2, and Gabra-4 to specific chromosomes with somatic cell hybrids, and we have positioned these genes by analysis of the progeny of three genetic crosses. Gabrb-1 and Gabra-2 are tightly linked on mouse Chromosome 5 between the markers Pgm-1 and Kit, and Gabra-4 maps to proximal mouse Chromosome 7 in apparent proximity to the previously mapped Gabrb-3. The Gabrb-1, Gabra-2 pair of genes on Chr 5 maps near the mouse "circling mutation" pi (pirouette).