title: Cuticle differentiation in the embryo of the amphipod crustacean Parhyale hawaiensis.
abstract: The arthropod cuticle is a multilayered extracellular matrix produced by the epidermis during embryogenesis and moulting. Molecularly and histologically, cuticle differentiation has been extensively investigated in the embryo of the insect Drosophila melanogaster. To learn about the evolution of cuticle differentiation, we have studied the histology of cuticle differentiation during embryogenesis of the amphipod crustacean Parhyale hawaiensis, which had a common ancestor with Drosophila about 510 million years ago. The establishment of the layers of the Parhyale juvenile cuticle is largely governed by mechanisms observed in Drosophila, e.g. as in Drosophila, the synthesis and arrangement of chitin in the inner procuticle are separate processes. A major difference between the cuticle of Parhyale and Drosophila concerns the restructuring of the Parhyale dorsal epicuticle after deposition. In contrast to the uniform cuticle of the Drosophila larva, the Parhyale cuticle is subdivided into two regions, the ventral and the dorsal cuticles. Remarkably, the boundary between the ventral and dorsal cuticles is sharp suggesting active extracellular regionalisation. The present analysis of Parhyale cuticle differentiation should allow the characterisation of the cuticle-producing and -organising factors of Parhyale (by comparison with the branchiopod crustacean Daphnia pulex) in order to contribute to the elucidation of fundamental questions relevant to extracellular matrix organisation and differentiation.
authors.affiliation: Max-Planck-Institut für Entwicklungsbiologie, Spemannstrasse 35, 72076 Tübingen, Germany.
authors.forename: Johanna
authors.initials: J
authors.lastname: Havemann
authors.forename: Ursula
authors.initials: U
authors.lastname: Müller
authors.forename: Jürgen
authors.initials: J
authors.lastname: Berger
authors.forename: Heinz
authors.initials: H
authors.lastname: Schwarz
authors.forename: Matthias
authors.initials: M
authors.lastname: Gerberding
authors.forename: Bernard
authors.initials: B
authors.lastname: Moussian
mesh_terms: D000595:Amino Acid Sequence; D033304:Amphipoda / Q000196:embryology* / Q000648:ultrastructure; D000818:Animals; D005075:Biological Evolution; D002454:Cell Differentiation; D002686:Chitin / Q000737:chemistry; D004330:Drosophila / Q000737:chemistry; D004625:Embryo, Nonmammalian / Q000648:ultrastructure*; D047108:Embryonic Development; D005109:Extracellular Matrix / Q000648:ultrastructure*; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D008969:Molecular Sequence Data; D016415:Sequence Alignment
chemical_list: D002686:Chitin