A novel gamma subunit of the GABAA receptor identified using the polymerase chain reaction.

We have utilized a polymerase chain reaction (PCR) strategy to identify a novel subunit, gamma 3, of the GABAA receptor. The gamma 3 cDNA encodes a mature protein of 450 amino acids that contains structural features typically conserved among subunits of the GABAA receptor family. The gamma 3 subunit shares approximately 66% sequence identity with the gamma 2 subunit but only 38% and 29% with alpha 1 and beta 1 subunits, respectively. Localization of the gamma 3 mRNA indicates that it is widely distributed throughout the mouse brain in a pattern similar to that observed for mRNAs encoding the gamma 2 subunits.