title: Shroom3 is required downstream of FGF signalling to mediate proneuromast assembly in zebrafish.
abstract: During development, morphogenetic processes require a precise coordination of cell differentiation, cell shape changes and, often, cell migration. Yet, how pattern information is used to orchestrate these different processes is still unclear. During lateral line (LL) morphogenesis, a group of cells simultaneously migrate and assemble radially organized cell clusters, termed rosettes, that prefigure LL sensory organs. This process is controlled by Fibroblast growth factor (FGF) signalling, which induces cell fate changes, cell migration and cell shape changes. However, the exact molecular mechanisms induced by FGF activation that mediate these changes on a cellular level are not known. Here, we focus on the mechanisms by which FGFs control apical constriction and rosette assembly. We show that apical constriction in the LL primordium requires the activity of non-muscle myosin. We demonstrate further that shroom3, a well-known regulator of non-muscle myosin activity, is expressed in the LL primordium and that its expression requires FGF signalling. Using gain- and loss-of-function experiments, we demonstrate that Shroom3 is the main organizer of cell shape changes during rosette assembly, probably by coordinating Rho kinase recruitment and non-muscle myosin activation. In order to quantify morphogenesis in the LL primordium in an unbiased manner, we developed a unique trainable 'rosette detector'. We thus propose a model in which Shroom3 drives rosette assembly in the LL downstream of FGF in a Rho kinase- and non-muscle myosin-dependent manner. In conclusion, we uncovered the first mechanistic link between patterning and morphogenesis during LL sensory organ formation.
authors.affiliation: Centre for Biological Signalling Studies, University of Freiburg, Schänzlestrasse 18, D-79104 Freiburg, Germany.
authors.forename: Sandra
authors.initials: S
authors.lastname: Ernst
authors.forename: Kun
authors.initials: K
authors.lastname: Liu
authors.forename: Sobhika
authors.initials: S
authors.lastname: Agarwala
authors.forename: Nicola
authors.initials: N
authors.lastname: Moratscheck
authors.forename: Mehmet Ender
authors.initials: ME
authors.lastname: Avci
authors.forename: Damian
authors.initials: D
authors.lastname: Dalle Nogare
authors.forename: Ajay B
authors.initials: AB
authors.lastname: Chitnis
authors.forename: Olaf
authors.initials: O
authors.lastname: Ronneberger
authors.forename: Virginie
authors.initials: V
authors.lastname: Lecaudey
mesh_terms: D000818:Animals; D030801:Animals, Genetically Modified; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002465:Cell Movement / Q000235:genetics / Q000502:physiology; D016764:Cell Polarity / Q000235:genetics; D004625:Embryo, Nonmammalian; D005346:Fibroblast Growth Factors / Q000378:metabolism* / Q000502:physiology; D053403:Lateral Line System / Q000196:embryology* / Q000378:metabolism / Q000502:physiology; D008465:Mechanoreceptors / Q000166:cytology / Q000378:metabolism / Q000502:physiology*; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009024:Morphogenesis / Q000235:genetics* / Q000502:physiology; D009218:Myosins / Q000378:metabolism; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014018:Tissue Distribution / Q000235:genetics; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*
chemical_list: D008840:Microfilament Proteins; C577864:Shroom3 protein, zebrafish; D029961:Zebrafish Proteins; D005346:Fibroblast Growth Factors; D009218:Myosins