A targeting vector was constructed to insert a cre/ERT2-Frt-neo-Frt cassette into the Sohlh1 gene by homologous recombination. The cre cassette was inserted at the ATG start codon, replacing exons 1-8. Chimeras were bred to C57BL/6 mice, and F1 animals were crossed to flp-expressing mice to remove the neo marker. (J:206011)