Monoclonal Antibodies to the Human γ₂ Subunit of the GABAA/Benzodiazepine Receptors

The large intracellular loop (IL) of the gamma 2 subunit of the cloned human gamma-aminobutyric acidA (GABAA) receptor (gamma 2 IL) was expressed in bacteria as glutathione-S-transferase and staphylococcal protein A fusion proteins. Mice were immunized with the fusion proteins (one protein per animal), and monoclonal antibodies were obtained. Six monoclonal antibodies reacted with the gamma 2 IL moiety of the fusion proteins. Three of these monoclonal antibodies also immunoprecipitated a high proportion of the GABAA/benzodiazepine receptors from bovine and rat brain and reacted with a wide 44,000-49,000-M(r) peptide band in immunoblots of affinity-purified GABAA receptors. These monoclonal antibodies are valuable reagents for the molecular characterization of the GABAA receptors in various brain regions.