Immunocytochemistry indicates that glycine-rich beta-proteins are present in the beta-layer, while cysteine-rich beta-proteins are present in beta- and alpha-layers of snake epidermis

Abstract

Immunolocalization of glycine-rich and cysteine–glycine-medium-rich beta-proteins (Beta-keratins) in snake epidermis indicates a different distribution between beta- and alpha-layers. Acta Zoologica, Stockholm. The epidermis of snakes consists of hard beta-keratin layers alternated with softer and pliable alpha-keratin layers. Using Western blot, light and ultrastructural immunolocalization, we have analyzed the distribution of two specific beta-proteins (formerly beta-keratins) in the epidermis of snakes. The study indicates that the antibody HgG5, recognizing glycine-rich beta-proteins of 12–15 kDa, is poorly or not reactive with the beta-layer of snake epidermis. This suggests that glycine-rich proteins similar to those present in lizards are altered during maturation of the beta-layer. Conversely, a glycine–cysteine-medium-rich beta-protein (HgGC10) of 10–12 kDa is present in beta- and alpha-layers, but it is reduced or disappears in precorneous and suprabasal cells destined to give rise to beta- and alpha-cells. Together with the previous studies on reptilian epidermis, the present results suggest that beta-proteins rich in glycine mainly accumulate on a scaffold of alpha-keratin producing a resistant and hydrophobic beta-layer. Conversely, beta-proteins lower in glycine but higher in cysteine accumulate on alpha-keratin filaments present in beta- and alpha-layers producing resistant but more pliable layers.