ANTIBODIES TO THE RAT BETA(3) SUBUNIT OF THE GAMMA-AMINOBUTYRIC ACID(A) RECEPTORS

Polymerase chain reaction was used to amplify the cDNA region that cod es for the large intracellular loop of the beta(3) subunit of the gamm a-aminobutyric acid(A)/benzodiazepine receptors (GABA(A)R/BZDR) from r at brain. The amplified cDNA was inserted into the prokaryotic express ion vector pGEX-3X and a fusion protein containing glutathione-S-trans ferase and beta(3) intracellular loop moieties was expressed in bacter ia. The fusion protein was affinity-purified and it was used to raise a rabbit anti-beta(3) antiserum. The anti-beta(3) antiserum immunoprec ipitated the gamma-aminobutyric acid(A) receptor from rat and bovine b rain. Immunoblots of the affinity-purified GABA(A)R/BZDR from bovine b rain revealed that the anti-beta(3) antiserum reacted with a 57 kDa pe ptide, whereas the monoclonal antibody 62-3G1 that recognized both bet a(2) and beta(3) reacted with 55 and 57 kDa peptides. The anti-beta(3) antiserum showed specificity for the beta(3) subunit vs beta(2) and b eta(1).