Ears of c-Jun/JunB knockout mice were topically treated with dithranol. Mice carrying floxed alleles for the JunB and c-Jun locus and expressing the K5-CreERT transgene received consecutive i.p. injections of tamoxifen for a period of 5 days, leading to deletion of both genes in the epidermis by inducible Cre-recombinase activity. One week after the last injection, psoriasis-like lesions on the ears were treated daily with vehicle (Vaseline) or dithranol in series of increasing concentrations.