Fig. 5.

Generation of mice with inducible GR loss-of-function restricted to adult keratinocytes (K14-cre-ER^T2//GR^loxP/loxP mice). A, Scheme depicting the structure of K14-Cre-ERT2 and GR^loxP/loxP transgenic lines. The K14-Cre-ERT2 transgene contains the human K14 promoter, the rabbit β-globin intron, the Cre-ERT2 coding sequence, and the SV40 polyadenylation (polyA) signal. The GR^loxP allele was generated by introducing two loxP sequences in the second and third introns. In the double transgenic K14-cre-ER^T2//GR^loxP/loxP mice treated with TAM, the recombinase under the control of the K14 promoter deletes the DNA fragment flanked by the loxP sites, rendering a GR^null allele exclusively in keratinocytes. The size of the PCR products corresponding to the GR^wt (225 bp), GR^loxP (275 bp), and GR^null (390 bp) alleles is indicated at the right. B, K14-cre-ER^T2//GR^loxP/loxP and 0-cre-ER^T2//GR^loxP/loxP adult mouse littermates were treated with TAM, and keratinocyte-specific recombination was assessed in epidermis (E) and dermis (D) from tail biopsies. Recombination was exclusively detected in the epidermis of TAM-treated K14-cre-ER^T2//GR^loxP/loxP and not 0-cre-ER^T2//GR^loxP/loxP mice. C, Immunoblotting using specific anti-GR antibody demonstrates the absence of GR protein specifically in the epidermis of K14-cre-ER^T2//GR^loxP/loxP mice. Actin was used as a loading control.