During Drosophila embryogenesis the process of dorsal closure (DC) results in continuity of the embryonic epidermis, and DC is well recognized as a model system for the analysis of epithelial morphogenesis as well as wound healing. During DC the flanking lateral epidermal sheets stretch, align, and fuse along the dorsal midline, thereby sealing a hole in the epidermis occupied by an extra-embry...

The thin skin of the left upper quadrant of the human abdomen has been studied by electron microscopy. Tissue removed with a high speed rotary punch was fixed in osmium tetroxide or potassium permanganate. The latter fixative in our preparations is superior to osmium for the demonstration of epidermal cell membranes and certain other membranous structures of the epidermis. The cytoplasmic membr...

This study investigated the phenotype and function of different antigen-presenting cells (APC) present within the epidermis of patients with cutaneous T-cell lymphoma (CTCL). Involved epidermis of CTCL compared with uninvolved was found to contain increased numbers of CD1+DR+ APC. This population was heterogeneous and comprised both leucocytes of a novel CD1+DR+CD36 (OKM5)+ phenotype and CD1+DR...

Keratinocyte growth factor (KGF) is a paracrine mediator of epithelial cell growth. To examine the direct effects of KGF on the morphogenesis of the epidermis, we generated skin equivalents in vitro by seeding human keratinocytes on the papillary surface of acellular dermis and raising them up to the air-liquid interface. KGF was either added exogenously or expressed by keratinocytes via a reco...

Notch signaling is involved in the cell fate determination of various cell lineages. Notch interaction with its ligand induces the cleavage of its intracellular domain (IC), and the Notch IC translocates to the nucleus and binds to RBP-J to transactivate transcription of target genes. All four Notches in mammals bind to RBP-J to exert their transactivation activities. Notch is expressed in deve...

To establish the animal body plan, embryos link the external epidermis to the internal digestive tract. In Caenorhabditis elegans, this linkage is achieved by the arcade cells, which form an epithelial bridge between the foregut and epidermis, but little is known about how development of these three epithelia is coordinated temporally. The arcade cell epithelium is generated after the epidermis...

Multiple small molecule hormones contribute to growth promotion or restriction in plants. Brassinosteroids (BRs), acting specifically in the epidermis, can both drive and restrict shoot growth. However, our knowledge of how BRs affect meristem size is scant. Here, we study the root meristem and show that BRs are required to maintain normal cell cycle activity and cell expansion. These two proce...

Owing to several recent developments, the cultivability of epidermal keratinocytes, particularly those of the human, has been greatly improved. Under the conditions used, single cultured cells generate stratified colonies that ultimately fuse and form an epithelium that is reasonable approximation of the epidermis. It will be shown here that large amounts of cultured epithelium can be generated...