title: Identification and comparative analysis of the epidermal differentiation complex in snakes.
abstract: The epidermis of snakes efficiently protects against dehydration and mechanical stress. However, only few proteins of the epidermal barrier to the environment have so far been identified in snakes. Here, we determined the organization of the Epidermal Differentiation Complex (EDC), a cluster of genes encoding protein constituents of cornified epidermal structures, in snakes and compared it to the EDCs of other squamates and non-squamate reptiles. The EDC of snakes displays shared synteny with that of the green anole lizard, including the presence of a cluster of corneous beta-protein (CBP)/beta-keratin genes. We found that a unique CBP comprising 4 putative beta-sheets and multiple cysteine-rich EDC proteins are conserved in all snakes and other squamates investigated. Comparative genomics of squamates suggests that the evolution of snakes was associated with a gene duplication generating two isoforms of the S100 fused-type protein, scaffoldin, the origin of distinct snake-specific EDC genes, and the loss of other genes that were present in the EDC of the last common ancestor of snakes and lizards. Taken together, our results provide new insights into the evolution of the skin in squamates and a basis for the characterization of the molecular composition of the epidermis in snakes.
authors.affiliation: Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria.|Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA), University of Bologna, Bologna, Italy.
authors.forename: Karin Brigit
authors.initials: KB
authors.lastname: Holthaus
authors.affiliation: Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Veronika
authors.initials: V
authors.lastname: Mlitz
authors.affiliation: Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Bettina
authors.initials: B
authors.lastname: Strasser
authors.affiliation: Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Erwin
authors.initials: E
authors.lastname: Tschachler
authors.affiliation: Dipartimento di Scienze Biologiche, Geologiche ed Ambientali (BiGeA), University of Bologna, Bologna, Italy.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Alibardi
authors.affiliation: Research Division of Biology and Pathobiology of the Skin, Department of Dermatology, Medical University of Vienna, Vienna, Austria.
authors.forename: Leopold
authors.initials: L
authors.lastname: Eckhart
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002454:Cell Differentiation / Q000235:genetics*; D004817:Epidermis / Q000378:metabolism*; D020440:Gene Duplication / Q000235:genetics; D023281:Genomics / Q000379:methods; D007633:Keratins / Q000235:genetics / Q000378:metabolism; D008116:Lizards / Q000235:genetics / Q000378:metabolism; D030162:Reptilian Proteins / Q000235:genetics / Q000378:metabolism; D012911:Snakes / Q000235:genetics / Q000378:metabolism*
chemical_list: D030162:Reptilian Proteins; D007633:Keratins