Transglutaminase 3 expression in C57BL/6J mouse embryo epidermis and the correlation with its differentiation.

Epidermal-type transglutaminase 3 (TGM3) is involved in the cross-linking of structural proteins to form the cornified envelope in the epidermis. In the present study, we detected the expression of TGM3 in the mouse embryo using RT-PCR. TGM3 mRNA is weakly presented from E11.5 to E14.5 and increases significantly from E15.5 to birth. Then we determined the spatial and temporal expression pattern of TGM3 in the skin and other organs by in situ hybridization. We found a deprivation of TGM3 in skin at E11.5, while a rich supply in periderm cells and a weak expression in basal cells from E12.5 to E14.5. From the period of E15.5 to E16.5, after keratinization in the epidermis, TGM3 was expressed in the granular and cornified layers. The electron microscopic observation of the C57BL/6J mouse limb bud skin development provided several morphological evidences for the epidermal differentiation. The above findings suggest that the expression of TGM3 plays a important role in the epidermis differentiation in embryogenesis.