LOCALIZATION OF ANNEXIN-I (LIPOCORTIN-I, P35) MESSENGER-RNA IN NORMALAND DISEASED HUMAN SKIN BY IN-SITU HYBRIDIZATION

Annexin I is a calcium- and phospholipid-binding protein that is invol ved in the regulation of cellular differentiation. The aim of the pres ent study was to determine the localization of annexin I mRNA expressi on in normal and diseased human skin, In situ hybridization with a spe cific digoxigenin-labelled RNA probe was used throughout, We detected no annexin I mRNA signals in basal and suprabasal cells of normal epid ermis, but positive signals were evident in the sudoriferous ducts, An nexin I mRNA expression was detected in the keratinizing squamous cell s in keratotic type seborrhoeic keratosis and in keratinocytes at the periphery of the horn pearl in well-differentiated squamous cell carci noma, Positive signals were also seen at the border between involved a nd noninvolved skin in psoriasis vulgaris and in dyskeratotic epiderma l keratinocytes in keratosis follicularis Darier. By contrast, no anne xin I mRNA signals were detected in tumour cells in basal cell carcino ma. The present results suggest that annexin I expression is related t o, and may play a role in, keratinization disorders.