The targeting vector was constructed containing a floxed exon 3 of the Lhx4 gene, an FRT-flanked En2 splicing acceptor-IRES-tdTomatopGK-Neo (tdT-Neo) cassette into the intron upstream of the exon 3 of the Lhx4. LoxP flanked exon 3 and the neo cassette was removed by cre recombinase leaving tdT reporter intact. (J:303030)