title: The Order and Place of Neuronal Differentiation Establish the Topography of Sensory Projections and the Entry Points within the Hindbrain.
abstract: Establishing topographical maps of the external world is an important but still poorly understood feature of the vertebrate sensory system. To study the selective innervation of hindbrain regions by sensory afferents in the zebrafish embryo, we mapped the fine-grained topographical representation of sensory projections at the central level by specific photoconversion of sensory neurons. Sensory ganglia located anteriorly project more medially than do ganglia located posteriorly, and this relates to the order of sensory ganglion differentiation. By single-plane illumination microscopy (SPIM) in vivo imaging, we show that (1) the sequence of arrival of cranial ganglion inputs predicts the topography of central projections, and (2) delaminated neuroblasts differentiate in close contact with the neural tube, and they never loose contact with the neural ectoderm. Afferent entrance points are established by plasma membrane interactions between primary differentiated peripheral sensory neurons and neural tube border cells with the cooperation of neural crest cells. These first contacts remain during ensuing morphological growth to establish pioneer axons. Neural crest cells and repulsive slit1/robo2 signals then guide axons from later-differentiating neurons toward the neural tube. Thus, this study proposes a new model by which the topographical representation of cranial sensory ganglia is established by entrance order, with the entry points determined by cell contact between the sensory ganglion cell bodies and the hindbrain.
authors.affiliation: Department of Experimental and Health Sciences, Universitat Pompeu Fabra, PRBB (Barcelona Biomedical Research Park), 08003 Barcelona, Spain and.
authors.forename: Andrea
authors.initials: A
authors.lastname: Zecca
authors.affiliation: Department of Experimental and Health Sciences, Universitat Pompeu Fabra, PRBB (Barcelona Biomedical Research Park), 08003 Barcelona, Spain and.
authors.forename: Sylvia
authors.initials: S
authors.lastname: Dyballa
authors.affiliation: Department of Experimental and Health Sciences, Universitat Pompeu Fabra, PRBB (Barcelona Biomedical Research Park), 08003 Barcelona, Spain and.
authors.forename: Adria
authors.initials: A
authors.lastname: Voltes
authors.affiliation: Department of Cell Biology and Neuroscience, Montana State University, Bozeman, Montana 59717.
authors.forename: Roger
authors.identifier: http://orcid.org/0000-0002-1392-6668
authors.initials: R
authors.lastname: Bradley
authors.affiliation: Department of Experimental and Health Sciences, Universitat Pompeu Fabra, PRBB (Barcelona Biomedical Research Park), 08003 Barcelona, Spain and cristina.pujades@upf.edu.
authors.forename: Cristina
authors.identifier: http://orcid.org/0000-0001-6423-7451
authors.initials: C
authors.lastname: Pujades
mesh_terms: D000344:Afferent Pathways / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D030801:Animals, Genetically Modified; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D001931:Brain Mapping; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology*; D054377:Chemokine CXCL12 / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004625:Embryo, Nonmammalian; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D018507:Gene Expression Regulation, Developmental / Q000235:genetics / Q000502:physiology*; D007555:Isoxazoles / Q000494:pharmacology; D060850:LIM-Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D000077339:Leflunomide; D008297:Male; D060172:Morpholinos / Q000494:pharmacology; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D054259:Neural Tube / Q000166:cytology; D012249:Rhombencephalon / Q000033:anatomy & histology* / Q000187:drug effects / Q000196:embryology; D011984:Sensory Receptor Cells / Q000187:drug effects / Q000502:physiology*; D015398:Signal Transduction / Q000235:genetics / Q000502:physiology; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D054377:Chemokine CXCL12; D004268:DNA-Binding Proteins; D004791:Enzyme Inhibitors; D007555:Isoxazoles; D060850:LIM-Homeodomain Proteins; D000077339:Leflunomide; D060172:Morpholinos; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C542436:Gal4 protein, zebrafish; C558563:isl2b protein, zebrafish; C093564:Neurogenic differentiation factor 1
keywords: axon navigation; inner ear; neural crest cells; neuron differentiation; sensory systems; somatotopy