A hypomorphic allele Ppargtm1Auwwas crossed successively with transgenic C57Bl/6J mice expressing FLP and Cre recombinases to remove the frt flanked neomycin selection cassette and the loxP flanked exon B specific for the Pparg2 isoform. Absence of Pparg2 isoform specific transcripts was confirmed by RTPCR.