In(7Peg3-Usp29)1Jkim

This allele was created by crossing mice carying the Usp29tm2Jkim allele with cre-expressing mice (Tg(Zp3-cre)93Knw). Usp29tm2Jkim was created as follows: a loxP site was inserted into intron 1 of Peg3 upstream of the Peg3-DMR (differentially methylated region). An FRT site flanked neomycin resistance gene cassette (in the same transcriptional direction as the targeted gene) and a second loxP site, in the opposite orientation of the first loxP site, were inserted into intron 1 of downstream neigbor Usp29, with which Peg3 shares a bidirectional promoter. Because of the opposite orientation of the two loxP sites, cre-mediated recombination inverts the ~4 kb Peg3-DMR region including the first exons of Peg3 and Usp29. This creates two fusion genes: one gene with Peg3 exon 1 followed by Usp29 exons 2-9, and the other gene with Usp29 exon 1 followed by Peg3 exons 2-9. Subsequent flp-mediated recombination removed the neo cassette, which would interfere with the transcription of the Usp29-Peg3 fusion gene. (J:245745)