Localization of transglutaminase 1 mRNA in normal and psoriatic epidermis by non-radioactive in situ hybridization.

We examined the expression of the transglutaminase 1 (TGase 1) gene in frozen sections of normal and psoriatic epidermis by means of non-radioactive in situ hybridization with digoxigenin-labelled cRNA probes. TGase 1 mRNA was expressed in the granular layer of normal epidermis, regardless of ortho- or hyperkeratosis. However, in psoriatic epidermis, TGase 1 mRNA was detected in the suprabasal spinous layer, but not in the subcorneal layer. These results indicate that TGase 1 gene expression is limited to the last stage of keratinization in normal epidermis and this regulation is disturbed in psoriasis.