Ancient origin of the gene encoding involucrin, a precursor of the cross-linked envelope of epidermis and related epithelia

• Published in: Proceedings of the National Academy of Sciences - PNAS Vol. 105; no. 40; pp. 15481 - 15486
• Main Authors: Vanhoutteghem, Amandine, Djian, Philippe, Green, Howard
• Format: Journal Article
• Language: English
• Published: United States National Academy of Sciences 07.10.2008; National Acad Sciences
• Subjects: Amino Acid Sequence; Amino acids; Animals; Base Sequence; Biochemistry, Molecular Biology; Biological Sciences; Birds; Chickens; Differentiation; Envelopes; Epidermal cells; Epidermis; Epidermis - metabolism; Epithelium - metabolism; Evolution; Evolution, Molecular; Genes; Genetic diversity; Glutamine; Humans; Keratinocytes; Life Sciences; Liver; Mammals; Models, Genetic; Molecular Sequence Data; Monodelphis - genetics; Monodelphis - metabolism; Placenta; Protein precursors; Protein Precursors - genetics; Protein-glutamine g-glutamyltransferase; Proteins; Sequence Alignment
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0807643105

The cross-linked (cornified) envelope is a characteristic product of terminal differentiation in the keratinocyte of the epidermis and related epithelia. This envelope contains many proteins of which involucrin was the first to be discovered and shown to become cross-linked by a cellular transglutaminase. Involucrin has evolved greatly in placental mammals, but retains the glutamine repeats that make it a good substrate for the transglutaminase. Until recently, it has been impossible to detect involucrin outside the placental mammals, but analysis of the GenBank and Ensembl databases that have become available since 2006 reveals the existence of involucrin in marsupials and birds. We describe here the properties of these involucrins and the ancient history of their evolution.