This transgenic cre-lox approach thus allowed to describe some of the fundamental roles of Jun proteins in several pathological conditions, as in psoriatic skin lesions in which epidermal keratinocytes show decreased expression of JunB, and inducible epidermal deletion of JunB and c-Jun causes a fulminant psoriasis-like skin disease and arthritis in mice [11]. The gene discussed is JUNB; the disease is Arthritis.