SUPRABASAL INTEGRIN EXPRESSION IN THE EPIDERMIS OF TRANSGENIC MICE RESULTS IN DEVELOPMENTAL DEFECTS AND A PHENOTYPE RESEMBLING PSORIASIS

Integrin expression is normally confined to the basal layer of the epi dermis, but when epidermal homeostasis is perturbed, the receptors are also expressed by suprabasal, differentiating keratinocytes. We have used the involucrin promoter to express functional human integrin subu nits alpha(2), alpha(5), and beta(1) in the suprabasal epidermal layer s of transgenic mice. In mice expressing alpha(5) or beta(1) alone or alpha(2) beta(1) or alpha(5) beta(1) heterodimers, there were hair and whisker abnormalities and a failure of eyelid fusion. In addition, mi ce expressing beta(1) alone or in combination with an or as exhibited epidermal hyperproliferation, perturbed keratinocyte differentiation, and skin inflammation, all of which are features of a common human ski n disease, psoriasis.