A STOP cassette (3x SV40 pol(A) signal sequence) and an FRT site flanked neomycin resistance gene cassette were inserted downstream of Hnf1aos1 and Hnf1aos2 promoter/1st exon (inside Hnf1a intron 1). The neo cassette was removed through subsequent flp-mediated recombination. The insertion prematurely terminates transcription of Hnf1aos1 and Hnf1aos2. (J:332319)