LOCALIZATION OF TYPE-I HUMAN SKIN COLLAGENASE IN DEVELOPING EMBRYONICAND FETAL SKIN

Type I human skin collagenase (HSC-1) was localized in developing embr yonic and fetal skin ranging from 6 to 20 weeks estimated gestational age using an antigen-specific, affinity-purified, polyclonal antiserum to HSC-1 and an avidin-biotin alkaline phosphatase procedure. Double immunolabeling with monoclonal antibodies for Factor VIII-related anti gen, type IV collagen, and the 68-kilodalton neurofilament subunit was performed using a direct peroxidase procedure. By 8 weeks estimated g estational age, HSC-1 localized to the periderm, the basal cell epider mal keratinocytes, dermal fibroblasts, and surrounding extracellular m atrix. At 12 weeks estimated gestational age, HSC-1 immunolabeling sho wed a continued association with the epidermis and dermis. Dermal and subcutaneous blood vessels and the surrounding extracellular matrix we re positive for HSC-1 labeling. HSC-1 staining was also found around d eveloping nerves and in association with dermal fibroblasts. In the de veloping hair follicle, HSC-1 was present in keratinocytes of the pre- germ, germ, hair peg, and bulbous hair peg. HSC-1 immunoreactivity was also found in association with the hair canal, the bulge, and the der mal papillae, but was absent from the fetal sebaceous gland. These dat a demonstrate the association of HSC-1 with the development of interfo llicular epidermis, the dermal collagenous matrix, the process of angi ogenesis, the development of nerves, and hair follicle morphogenesis.