Tsikolia, Nikoloz

[["dc.bibliographiccitation.artnumber","4"],["dc.bibliographiccitation.issue","1"],["dc.bibliographiccitation.journal","EvoDevo"],["dc.bibliographiccitation.volume","9"],["dc.contributor.author","Kremnyov, Stanislav"],["dc.contributor.author","Viebahn, Christoph"],["dc.contributor.author","Tsikolia, Nikoloz"],["dc.contributor.author","Henningfeld, Kristine A."],["dc.date.accessioned","2018-04-18T14:43:20Z"],["dc.date.accessioned","2021-10-27T13:21:04Z"],["dc.date.available","2018-04-18T14:43:20Z"],["dc.date.available","2021-10-27T13:21:04Z"],["dc.date.issued","2018-01-31"],["dc.date.updated","2018-04-18T14:43:20Z"],["dc.description.abstract","Abstract Background The notochord has organizer properties and is required for floor plate induction and dorsoventral patterning of the neural tube. This activity has been attributed to sonic hedgehog (shh) signaling, which originates in the notochord, forms a gradient, and autoinduces shh expression in the floor plate. However, reported data are inconsistent and the spatiotemporal development of the relevant shh expression domains has not been studied in detail. We therefore studied the expression dynamics of shh in rabbit, chicken and Xenopus laevis embryos (as well as indian hedgehog and desert hedgehog as possible alternative functional candidates in the chicken). Results Our analysis reveals a markedly divergent pattern within these vertebrates: whereas in the rabbit shh is first expressed in the notochord and its floor plate domain is then induced during subsequent somitogenesis stages, in the chick embryo shh is expressed in the prospective neuroectoderm prior to the notochord formation and, interestingly, prior to mesoderm immigration. Neither indian hedgehog nor desert hedgehog are expressed in these midline structures although mRNA of both genes was detected in other structures of the early chick embryo. In X. laevis, shh is expressed at the beginning of gastrulation in a distinct area dorsal to the dorsal blastopore lip and adjacent to the prospective neuroectoderm, whereas the floor plate expresses shh at the end of gastrulation. Conclusions While shh expression patterns in rabbit and X. laevis embryos are roughly compatible with the classical view of “ventral to dorsal induction” of the floor plate, the early shh expression in the chick floor plate challenges this model. Intriguingly, this alternative sequence of domain induction is related to the asymmetrical morphogenesis of the primitive node and other axial organs in the chick. Our results indicate that the floor plate in X. laevis and chick embryos may be initially induced by planar interaction within the ectoderm or epiblast. Furthermore, we propose that the mode of the floor plate induction adapts to the variant topography of interacting tissues during gastrulation and notochord formation and thereby reveals evolutionary plasticity of early embryonic induction."],["dc.identifier.doi","10.1186/s13227-017-0090-x"],["dc.identifier.pmid","29423139"],["dc.identifier.purl","https://resolver.sub.uni-goettingen.de/purl?gs-1/15170"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/91992"],["dc.language.iso","en"],["dc.language.rfc3066","en"],["dc.notes.intern","Migrated from goescholar"],["dc.relation.issn","2041-9139"],["dc.relation.orgunit","Universitätsmedizin Göttingen"],["dc.rights","CC BY 4.0"],["dc.rights.holder","The Author(s)"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0"],["dc.subject.ddc","610"],["dc.title","Divergent axial morphogenesis and early shh expression in vertebrate prospective floor plate"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.version","published_version"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","957211"],["dc.bibliographiccitation.journal","Frontiers in Cell and Developmental Biology"],["dc.bibliographiccitation.volume","10"],["dc.contributor.affiliation","Negretti, Maria Isabella; \r\n1\r\nAnatomy and Embryology, University Medical Center Göttingen, Göttingen, Germany"],["dc.contributor.affiliation","Böse, Nina; \r\n1\r\nAnatomy and Embryology, University Medical Center Göttingen, Göttingen, Germany"],["dc.contributor.affiliation","Petri, Natalia; \r\n2\r\nDepartment of Embryology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia"],["dc.contributor.affiliation","Kremnyov, Stanislav; \r\n2\r\nDepartment of Embryology, Faculty of Biology, Lomonosov Moscow State University, Moscow, Russia"],["dc.contributor.affiliation","Tsikolia, Nikoloz; \r\n1\r\nAnatomy and Embryology, University Medical Center Göttingen, Göttingen, Germany"],["dc.contributor.author","Negretti, Maria Isabella"],["dc.contributor.author","Böse, Nina"],["dc.contributor.author","Petri, Natalia"],["dc.contributor.author","Kremnyov, Stanislav"],["dc.contributor.author","Tsikolia, Nikoloz"],["dc.date.accessioned","2022-10-04T10:21:48Z"],["dc.date.available","2022-10-04T10:21:48Z"],["dc.date.issued","2022"],["dc.date.updated","2022-11-11T13:13:24Z"],["dc.description.abstract","Development of visceral left–right asymmetry in bilateria is based on initial symmetry breaking followed by subsequent asymmetric molecular patterning. An important step is the left-sided expression of transcription factor\r\n pitx2\r\n which is mediated by asymmetric expression of the\r\n nodal\r\n morphogen in the left lateral plate mesoderm of vertebrates. Processes leading to emergence of the asymmetric\r\n nodal\r\n domain differ depending on the mode of symmetry breaking. In\r\n Xenopus laevis\r\n and mouse embryos, the leftward fluid flow on the ventral surface of the left–right organizer leads through intermediate steps to enhanced activity of the nodal protein on the left side of the organizer and subsequent asymmetric\r\n nodal\r\n induction in the lateral plate mesoderm. In the chick embryo, asymmetric morphogenesis of axial organs leads to paraxial\r\n nodal\r\n asymmetry during the late gastrulation stage. Although it was shown that hedgehog signaling is required for initiation of the\r\n nodal\r\n expression, the mechanism of its asymmetry remains to be clarified. In this study, we established the activation of hedgehog signaling in early chick embryos to further study its role in the initiation of asymmetric\r\n nodal\r\n expression. Our data reveal that hedgehog signaling is sufficient to induce the\r\n nodal\r\n expression in competent domains of the chick embryo, while treatment of\r\n Xenopus\r\n embryos led to moderate\r\n nodal\r\n inhibition. We discuss the role of symmetry breaking and competence in the initiation of asymmetric gene expression."],["dc.description.sponsorship","Open-Access-Publikationsfonds 2022"],["dc.identifier.doi","10.3389/fcell.2022.957211"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/114505"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-600"],["dc.publisher","Frontiers Media S.A."],["dc.relation.eissn","2296-634X"],["dc.rights","CC BY 4.0"],["dc.rights.uri","https://creativecommons.org/licenses/by/4.0/"],["dc.title","Nodal asymmetry and hedgehog signaling during vertebrate left–right symmetry breaking"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]