title: Formation of adherens and communicating junctions coordinate the differentiation of the shedding-layer and beta-epidermal generation in regenerating lizard epidermis.
abstract: In the lizard epidermis, the formation of a stratified alpha- and beta-layer, separated by a shedding complex for molting, suggests that keratinocytes communicate in a coordinated manner after they leave the basal layers during the shedding cycle. I have therefore studied the localization of cell junctional proteins such as beta-catenin and connexins 43 and 26 during scale regeneration in lizard using immunocytochemistry. Beta-catenin is also detected in nuclei of basal cells destined to give rise to the Oberhäutchen and beta-cells suggesting activation of the Wnt-pathway during beta-cell differentiation. The observations show that cells of the entire shedding layer (clear and Oberhäutchen) and beta-layer are connected by beta-catenin (adherens junctions) and connexins (communicating junctions) during their differentiation. This likely cell coupling determines the formation of a distinct shedding and beta-layer within the regenerating epidermis. The observed pattern of cell junctional stratification suggests that after departing from the basal layer Oberhäutchen and beta-cells form a continuous communicating compartment that coordinates the contemporaneous differentiation along the entire scale. While the beta-layer matures the junctions are lost while other cell junctions are formed in the following mesos- and alpha-cell layers. This process determines the formation of layers with different texture (harder or softer) and the precise localization of the shedding layer within lizard epidermis.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Alibardi
mesh_terms: D000818:Animals; D002454:Cell Differentiation; D000072259:Connexin 26; D018031:Connexin 43 / Q000378:metabolism; D017630:Connexins / Q000378:metabolism; D000078404:Epidermal Cells; D004817:Epidermis / Q000502:physiology; D005260:Female; D007365:Intercellular Junctions; D008116:Lizards / Q000502:physiology*; D008297:Male; D012038:Regeneration; D030162:Reptilian Proteins / Q000378:metabolism; D013623:Tail / Q000166:cytology / Q000502:physiology*; D051176:beta Catenin / Q000378:metabolism
chemical_list: D018031:Connexin 43; D017630:Connexins; D030162:Reptilian Proteins; D051176:beta Catenin; D000072259:Connexin 26