The coding region was replaced with a coding region containing substitution that results in an amino acid substution of a glutamine for an arginine at position 43 (R43Q), 4 aditional silent mutations (not identified) and a floxed neo cassette that was subsequently removed by cre-mediated recombination. Expression levels were confirmed to be normal by RT-PCR analysis on total brain extracts. Reduction in protein product was confirmed by wesrtern blot analysis on extracts from E16 forebrains. This allele was generated from Gabrg2tm2Spet.