Tsikolia, Nikoloz

[["dc.bibliographiccitation.artnumber","e0275164"],["dc.bibliographiccitation.issue","11"],["dc.bibliographiccitation.journal","PLOS ONE"],["dc.bibliographiccitation.volume","17"],["dc.contributor.author","Petri, Natalia"],["dc.contributor.author","Nordbrink, Rhea"],["dc.contributor.author","Tsikolia, Nikoloz"],["dc.contributor.author","Kremnyov, Stanislav"],["dc.contributor.editor","Brand, Thomas"],["dc.date.accessioned","2022-12-01T08:31:27Z"],["dc.date.available","2022-12-01T08:31:27Z"],["dc.date.issued","2022"],["dc.description.abstract","Left-right symmetry breaking in most studied vertebrates makes use of so-called leftward flow, a mechanism which was studied in detail especially in mouse and\r\n Xenopus laevis\r\n embryos and is based on rotation of monocilia on specialized epithelial surface designated as left-right organizer or laterality coordinator. However, it has been argued that prior to emergence of leftward flow an additional mechanism operates during early cleavage stages in\r\n Xenopus\r\n embryo which is based on cytoskeletal processes. Evidence in favour of this early mechanism was supported by left-right abnormalities after chemical inhibition of cytoskeletal protein formin. Here we analyzed temporal dimension of this effect in detail and found that reported abnormalities arise only after treatment at gastrula-neurula stages, i.e. just prior to and during the operation of left-right organizer. Moreover, molecular and morphological analysis of the left-right organizer reveals its abnormal development. Our results strongly indicate that left-right abnormalities reported after formin inhibition cannot serve as support of models based on early symmetry breaking event in\r\n Xenopus\r\n embryo."],["dc.description.sponsorship"," Lomonosov Moscow State University http://dx.doi.org/10.13039/501100016971"],["dc.description.sponsorship"," Koltzov Institute of Developmental Biology, Russian Academy of Sciences http://dx.doi.org/10.13039/501100014785"],["dc.description.sponsorship","Göttingen University"],["dc.identifier.doi","10.1371/journal.pone.0275164"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/118169"],["dc.language.iso","en"],["dc.notes.intern","DOI-Import GROB-621"],["dc.relation.eissn","1932-6203"],["dc.rights.uri","http://creativecommons.org/licenses/by/4.0/"],["dc.title","Abnormal left-right organizer and laterality defects in Xenopus embryos after formin inhibitor SMIFH2 treatment"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["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"]]