Tg(KRT5-cre/ERT)SCmch

This transgene comprises 5.2 kb of 5' flanking and promoter DNA from the bovine keratin 5 gene and a rabbit beta-globin intron followed by the Cre recombinase coding sequence joined in-frame to a mutated estrogen receptor ligand binding domain (ERT), then by an SV40 poly(A) signal and two reversed copies of the ~1.2 kb HS4 5' insulator sequence from the chicken beta-globin gene. Double transgenic mice for cre and the R26-LacZ reporter demonstrate constitive expression (in absence of 4-hydroxy tamoxifen treatment) from about E14.5 in most keratin 5 expressing tissues; the thymic epithelium and the Mullerian vagina show significant expression only after postnatal day 7. Additionally, only this line (in contrast with Tg(KRT5-Cre/ERT)ICmch) exhibits Cre recombinase activity in KRT5-expressing epithelial cells of the mammary gland. (J:143780)