title: Presence of a glycine-cysteine-rich beta-protein in the oberhautchen layer of snake epidermis marks the formation of the shedding layer.
abstract: The complex differentiation of snake epidermis largely depends on the variation in the production of glycine-cysteine-rich versus glycine-rich beta-proteins (beta-keratins) that are deposited on a framework of alpha-keratins. The knowledge of the amino acid sequences of beta-proteins in the snake Pantherophis guttatus has allowed the localization of a glycine-cysteine-rich beta-protein in the spinulated oberhautchen layer of the differentiating shedding complex before molting takes place. This protein decreases in the beta-layer and disappears in mesos and alpha-layers. Conversely, while the mRNA for a glycine-rich beta-protein is highly expressed in differentiating beta-cells, the immunolocalization for this protein is low in these cells. This discrepancy between expression and localization suggests that the epitope in glycine-rich beta-proteins is cleaved or modified by posttranslational processes that take place during the differentiation and maturation of the beta-layer. The present study suggests that among the numerous beta-proteins coded in the snake genome to produce epidermal layers with different textures, the glycine-cysteine-rich beta-protein marks the shedding complex formed between alpha- and beta-layers that allows for molting while its disappearance between the beta- and alpha-layers (mesos region for scale growth) is connected to the formation of the alpha-layers.
authors.affiliation: Comparative Histolab and Dipartimento di Biologia, Geologia e Scienze Ambientali, Università di Bologna, Bologna, Italy, lorenzo.alibardi@unibo.it.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Alibardi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D017812:Colubridae / Q000033:anatomy & histology* / Q000502:physiology*; D004817:Epidermis / Q000378:metabolism* / Q000648:ultrastructure; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation; D017403:In Situ Hybridization; D008954:Models, Biological; D008969:Molecular Sequence Data; D018978:Molting / Q000502:physiology*; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D011506:Proteins; D012333:RNA, Messenger