Immunogold Labeling Shows that Glycine-Cysteine-Rich Beta-Proteins are Deposited in the Oberhautchen Layer of Snake Epidermis in Preparation to Shedding

Shedding in snakes is cyclical and derives from the differentiation of an intraepidermal shedding complex made of two different layers, termed clear and Oberhautchen that determine the separation between the outer from the inner epidermal generation that produces a molt. The present comparative immunocytochemical study on the epidermis and molts of different species of snakes shows that a glycine-cysteine-rich corneous beta-protein in a snake is prevalently accumulated in cells of the Oberhautchen layer and decreases in those of the beta-layer. The protein is variably distributed in the mature beta-layer of species representing some snake families when the beta-layer merges with the Oberhautchen but disappears in alpha-layers. Therefore, this protein represents an early marker of the transition between the outer and the inner epidermal generations in the epidermis of snakes in general. It is hypothesized that specific gene activation for glycine-cysteine-rich corneous beta-proteins occurs during the passage from the clear layer of the outer epidermal generation to the Oberhautchen layer of the replacing inner epidermal generation. It is suggested that in the epidermis of most species glycine-cysteine-rich corneous beta-proteins form part of the dense corneous material that rapidly accumulates in the differentiating Oberhautchen cells but decreases in the following beta-layer of the inner epidermal generation destined to be separated from the previous outer generation in the process of shedding. The regulation of the synthesis of these and other proteins is, therefore, crucial in timing the different stages of the shedding cycle in lepidosaurian reptiles. J. Morphol. 276:144-151, 2015. (c) 2014 Wiley Periodicals, Inc.