Koebernick, Katja

[["dc.bibliographiccitation.firstpage","325"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Developmental Biology"],["dc.bibliographiccitation.lastpage","338"],["dc.bibliographiccitation.volume","260"],["dc.contributor.author","Koebernick, K."],["dc.contributor.author","Hollemann, T."],["dc.contributor.author","Pieler, T."],["dc.date.accessioned","2018-11-07T10:36:57Z"],["dc.date.available","2018-11-07T10:36:57Z"],["dc.date.issued","2003"],["dc.description.abstract","Vertebrate inner ear development is initiated by the specification of the otic placode, an ectodermal structure induced by signals from neighboring tissue. Although several signaling molecules have been identified as candidate otic inducers, many details of the process of inner ear induction remain elusive. Here, we report that otic induction is responsive to the level of Hedgehog (Hh) signaling activity in Xenopus, making use of both gain- and loss-of-function approaches. Ectopic activation of Hedgehog signaling resulted in the development of ectopic vesicular structures expressing the otic marker genes XPax-2, Xdll-3, and Xwnt-3A, thus revealing otic identity. Induction of ectopic otic vesicles was also achieved by misexpression of two different inhibitors of Hh signaling: the putative Hh antagonist mHIP and XPtc lDeltaLoop2, a dominant-negative form of the Hh receptor Patched. In addition, misexpression of XPtc I DeltaLoop2 as well as treatment of Xenopus embryos with the specific Hh signaling antagonist cyclopamine resulted in the formation of enlarged otic vesicles. In summary, our observations suggest that a defined level of Hh signaling provides a restrictive environment for otic fate in Xenopus embryos. (C) 2003 Elsevier Science (USA). All rights reserved."],["dc.identifier.doi","10.1016/S0012-1606(03)00242-2"],["dc.identifier.isi","000184946000004"],["dc.identifier.pmid","12921735"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/45447"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Academic Press Inc Elsevier Science"],["dc.relation.issn","0012-1606"],["dc.title","A restrictive role for Hedgehog signalling during otic specification in Xenopus"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","303"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Mechanisms of Development"],["dc.bibliographiccitation.lastpage","308"],["dc.bibliographiccitation.volume","100"],["dc.contributor.author","Koebernick, K."],["dc.contributor.author","Hollemann, T."],["dc.contributor.author","Pieler, T."],["dc.date.accessioned","2018-11-07T09:25:21Z"],["dc.date.available","2018-11-07T09:25:21Z"],["dc.date.issued","2001"],["dc.description.abstract","Inductive signaling mediated by secreted factors of the Hedgehog (Hh) gene family regulates cellular proliferation and differentiation in many embryonic tissues. Two transmembrane proteins associated in a complex, Patched (Ptc) and Smoothened (Smo), are indispensable for the reception of Hh signals (Cell 86 (1996) 221; Nature 382 (1996) 547; Nature 384 (1996) 176; Nature 384 (1996) 129). Here, we report on the identification of Pre and Smo homologues from Xenopus and analyze their spatio-temporal expression during embryogenesis. The intracellular response to Hh signals involves upregulation of Ptc transcription (Genes Dev. 10 (1996) 301; J. Biol. Chem. 271 (1996) 12125). In accordance with its putative function as Shh target gene, XPtc1 expression during early stages of Xenopus embryogenesis is detected in mesodermal and neuroectodermal tissues proximal to the notochord, a known expression domain of Shh. Although the expression pattern of XPtc1 was similar to that of other vertebrates, expression domains specific to Xenopus could be detected in the hypochord, dorsal mesencephalon, otic vesicles and pituitary anlage. Unlike other vertebrate Ptc1 homologues, semitic expression of XPtc1 is confined to a central cell layer. In contrast to the tissue-specific expression characteristics of XPtc1, XSmo expression appears to be ubiquitously activated in early embryonic stages but condenses in the terminal regions of the embryo at tailbud stage. In many tissues and organs of the adult, XPtc1 and XSmo are found to display similar expression levels. (C) 2001 Elsevier Science Ireland Ltd. All rights reserved."],["dc.identifier.doi","10.1016/S0925-4773(00)00526-8"],["dc.identifier.isi","000166837600013"],["dc.identifier.pmid","11165486"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30042"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1872-6356"],["dc.relation.issn","0925-4773"],["dc.title","Molecular cloning and expression analysis of the Hedgehog receptors XPtc1 and XSmo in Xenopus laevis"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]