A fragment from serine racemase (Srr) BAC RP23-174M12 (RZPD) containing exons 39 was used as a targeting vector to insert two loxP sites flanking exons 26 followed by a 1.6-kb FRT-PGK-gb2-neo-FRT loxP fragment. After FLP recombination, the FRT-PGK-gb2-neo-FRT cassette is excised, leaving a single FRT and loxP sites. Germline cre recombinase deleted floxed exons 2-6. (J:319913)