GABAA receptor beta 1, beta 2, and beta 3 subunits: comparisons in DBA/2J and C57BL/6J mice

GABAA receptors link binding of GABA (gamma-aminobutyric acid) to inhibitory chloride flux in the brain. They are the site of action of several important classes of drugs, and have been implicated in animal models of epilepsy and in the actions of alcohol. We compare the sequence and expression of the beta 1, beta 2 and beta 3 subunits of GABAA receptors in two inbred strains of mice, DBA/2J and C57BL/6J, which differ markedly in seizure susceptibility and in a variety of behaviors related to alcohol. Only the beta 3 subunit had strain differences in cDNA nucleotide sequence, which did not affect amino acid sequence but which did create restriction fragment length polymorphisms (RFLPs) potentially useful in gene mapping. We have also tested mouse beta 1 and beta 2 subunits for internal alternative splicing, detecting none.