Regeneration of the dermoepidermal junction in anuran larval skin

Abstract In anuran larval skin, several ultrastructures are formed at the dermoepidermal interface, and these include half‐desmosomes, basal lamina, and anchoring fibrils. Regional differences in the tadpole skin were assessed in terms of the process of regeneration of the junctional structures. The dermoepidermal interface was specifically destroyed by treatment with a neutral protease at pre‐ (stage V), pro‐ (stage XVIII), and climactic metamorphosis (stage XXI). The regeneration of the junctional structures was then compared between the skin of the tail and the back. Regardless of the metamorphic stages, the back skin regenerated complete structures, which contained the same number of half‐desmosomes as in the control, within 3 days after treatment. In the tail skin from tadpoles at premetamorphosis, basal lamina and half‐desmosomes were regenerated 2 days later than was the back skin. The ability of the tail skin to regenerate decreased as metamorphosis proceeded. When the enzymatic treatment was performed on skin removed at the climax of metamorphosis, the tail skin underwent histolysis without completion of junctional repair. In experiments with heterotypically recombined skins, active regeneration similar to that of the back skin was observed in recombinants of tail epidermis and back dermis. However, the recombinants of back dermis with tail dermis produced only basal lamina and amorphous material beneath the epidermis. These results suggest that a regional difference, with respect to the regenerating ability of the dermoepidermal junction, already exists in the skin of the premetamorphic tadpole and that this difference depends on the dermal components of the skin.