title: Eph receptors and ephrin class B ligands are expressed at tissue boundaries in Hydra vulgaris.
abstract: Eph receptors and ephrins are important players in axon guidance, cell sorting and boundary formation. Both the receptors and the ligands are integrated transmembrane proteins and signalling is bidirectional. The prevalent outcome of signal transduction is repulsion of adjacent cells or cell populations. Eph/ephrins have been identified in all multicellular animals from human to sponge, their functions however appear to have been altered during evolution. Here we have identified four Eph receptors and three class B ligands in the cnidarian Hydra vulgaris, indicating that those are the evolutionary older ones. In situ hybridisation experiments revealed a striking complementarity of expression of receptors and ligands in tentacles and in developing buds. This suggests that the original function of ephrin signalling may have been in epithelial cell adhesion and the formation of tissue boundaries.
authors.affiliation: Department of Biology 2, Ludwig-Maximilians-Universität München, Germany.
authors.forename: Susanne
authors.initials: S
authors.lastname: Tischer
authors.forename: Mona
authors.initials: M
authors.lastname: Reineck
authors.forename: Johannes
authors.initials: J
authors.lastname: Söding
authors.forename: Sandra
authors.initials: S
authors.lastname: Münder
authors.forename: Angelika
authors.initials: A
authors.lastname: Böttger
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002448:Cell Adhesion / Q000502:physiology*; D036342:Ephrins / Q000096:biosynthesis*; D004847:Epithelial Cells / Q000378:metabolism; D006829:Hydra; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D036081:Receptors, Eph Family / Q000096:biosynthesis*; D016415:Sequence Alignment; D015398:Signal Transduction
chemical_list: D036342:Ephrins; D036081:Receptors, Eph Family