title: Characterization of beta-keratins in lizard epidermis: electrophoresis, immunocytochemical and in situ-hybridization study.
abstract: Lizard scales are composed of alpha-(cyto-) keratins and beta-keratins. The characterization of the molecular weight and isoelectric point (pI) of alpha- and beta-keratins of lizard epidermis (Podarcis sicula) has been done by using two-dimensional electrophoresis, immunoblotting, and immunocytochemistry. Antibodies against cytokeratins, against a chicken scale beta-keratin or against lizard beta-keratin bands of 15-16kDa, have been used to recognize alpha- and beta-keratins. Acid and basic cytokeratins of 42-67kDa show a pI from 5.0 to 8.9. This indicates the presence of specific keratins for the formation of the stratum corneum. Main protein spots of beta-keratin at 15-17kDa, and pI at 8.5, 8.2, and 6.7, and one spot at 10kDa and pI at 7.3 were recognized. Therefore, beta-keratins are mainly basic proteins, and are used for the formation of the hard corneous layer of the epidermis. Ultrastructural immunocytochemistry confirms that beta-keratin is packed into large and dense bundles of beta-keratin cells of lizard epidermis. The use of a probe against a lizard beta-keratin in situ-hybridization studies confirms that the mRNA for beta-keratins is present in beta-cells and is localized around or even associated with beta-keratin filaments.
authors.affiliation: Dipartimento di Biologia Evoluzionistica Sperimentale, University of Bologna, via Selmi 3, 40126 Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Toni
authors.forename: L
authors.initials: L
authors.lastname: Alibardi
mesh_terms: D008841:Actin Cytoskeleton / Q000378:metabolism / Q000648:ultrastructure; D000818:Animals; D000918:Antibody Specificity / Q000276:immunology; D015180:Electrophoresis, Gel, Two-Dimensional; D004817:Epidermis / Q000378:metabolism* / Q000648:ultrastructure; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D007526:Isoelectric Point; D015603:Keratinocytes / Q000378:metabolism* / Q000648:ultrastructure; D007633:Keratins / Q000737:chemistry / Q000276:immunology; D008116:Lizards / Q000033:anatomy & histology / Q000378:metabolism*; D046529:Microscopy, Electron, Transmission; D008970:Molecular Weight; D012333:RNA, Messenger / Q000378:metabolism; D053800:beta-Keratins / Q000737:chemistry* / Q000235:genetics / Q000276:immunology
chemical_list: D012333:RNA, Messenger; D053800:beta-Keratins; D007633:Keratins