Expression of Laminin, Type IV Collagen and Fibronectin Molecules Is Related to Embryonal Skin and Epidermal Appendage Morphogenesis.

The study investigated the expression of laminin, type IV collagen, and fibronectin in the basement membranes of fetal human skin between 12 to 21 weeks of gestational age. It was found that these proteins, which are crucial for cellular processes such as adhesion and differentiation, began to express in the germinative epithelial cells of the skin at the hair follicle bulbs. Fibronectin expression started at the 12th week, while laminin and collagen type IV began at the 19th week. By 20 to 21 weeks, these proteins progressively involved the epithelial epidermal cells and the basement membrane at the dermal-epidermal junction, indicating their role in skin and epidermal appendage morphogenesis.