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1.
Evol Dev ; 26(2): e12474, 2024 Mar.
Article in English | MEDLINE | ID: mdl-38425004

ABSTRACT

The telencephalon of ray-finned fishes undergoes eversion, which is very different to the evagination that occurs in most other vertebrates. Ventricle morphogenesis is key to build an everted telencephalon. Thus, here we use the apical marker zona occludens 1 to understand ventricle morphology, extension of the tela choroidea and the eversion process during early telencephalon development of four teleost species: giant danio (Devario aequipinnatus), blind cavefish (Astyanax mexicanus), medaka (Oryzias latipes), and paradise fish (Macroposus opercularis). In addition, by using immunohistochemistry against tubulin and calcium-binding proteins, we analyze the general morphology of the telencephalon, showing changes in the location and extension of the olfactory bulb and other telencephalic regions from 2 to 5 days of development. We also analyze the impact of abnormal eye and telencephalon morphogenesis on eversion, showing that cyclops mutants do undergo eversion despite very dramatic abnormal eye morphology. We discuss how the formation of the telencephalic ventricle in teleost fish, with its characteristic shape, is a crucial event during eversion.


Subject(s)
Fishes , Telencephalon , Animals , Larva , Telencephalon/anatomy & histology , Vertebrates , Morphogenesis
2.
EMBO Rep ; 23(11): e52493, 2022 11 07.
Article in English | MEDLINE | ID: mdl-36194673

ABSTRACT

Our understanding of the cell behaviours and cytoskeletal requirements of axon formation is largely derived from in vitro models but how these relate to axon formation in vivo is not clear. In vitro, neurons progress through a well-defined multineurite stage to form an axon and both actin and microtubules cooperate to drive the first steps in neurite and axon morphogenesis. However, these steps are not recapitulated in vivo, and it is not clear whether the underlying cell biological mechanisms may differ also. Here, we investigate the mechanisms that regulate axon formation in embryonic zebrafish spinal neurons in vivo. We find microtubule organising centres are located distant from the site of axon initiation, and microtubule plus-ends are not enriched in the axon during axon initiation. Focal F-actin accumulation precedes axon formation, and we find that nocodazole-treated neurons with no detectable microtubules are still able to form nascent axonal protrusions that are approximately 10-µm long, dilated and relatively long-lived. We suggest spinal axon formation in vivo is fundamentally different from axon formation in in vitro models.


Subject(s)
Microtubules , Zebrafish , Animals , Axons/physiology , Neurons , Neurites , Actins
3.
Development ; 147(24)2020 12 23.
Article in English | MEDLINE | ID: mdl-33361092

ABSTRACT

Using the zebrafish neural tube as a model, we uncover the in vivo mechanisms allowing the generation of two opposing apical epithelial surfaces within the centre of an initially unpolarised, solid organ. We show that Mpp5a and Rab11a play a dual role in coordinating the generation of ipsilateral junctional belts whilst simultaneously releasing contralateral adhesions across the centre of the tissue. We show that Mpp5a- and Rab11a-mediated resolution of cell-cell adhesions are both necessary for midline lumen opening and contribute to later maintenance of epithelial organisation. We propose that these roles for both Mpp5a and Rab11a operate through the transmembrane protein Crumbs. In light of a recent conflicting publication, we also clarify that the junction-remodelling role of Mpp5a is not specific to dividing cells.


Subject(s)
Guanylate Cyclase/genetics , Morphogenesis/genetics , Zebrafish Proteins/genetics , Zebrafish/growth & development , rab GTP-Binding Proteins/genetics , Animals , Cell Polarity/genetics , Epithelial Cells/metabolism , Gene Expression Regulation, Developmental/genetics , Intercellular Junctions/genetics , Membrane Proteins , Neural Tube/growth & development , Zebrafish/genetics
4.
Dev Cell ; 49(6): 907-919.e10, 2019 06 17.
Article in English | MEDLINE | ID: mdl-31211994

ABSTRACT

During early spinal cord development, neurons of particular subtypes differentiate with a sparse periodic pattern while later neurons differentiate in the intervening space to eventually produce continuous columns of similar neurons. The mechanisms that regulate this spatiotemporal pattern are unknown. In vivo imaging in zebrafish reveals that differentiating spinal neurons transiently extend two long protrusions along the basal surface of the spinal cord before axon initiation. These protrusions express Delta protein, consistent with the hypothesis they influence Notch signaling at a distance of several cell diameters. Experimental reduction of Laminin expression leads to smaller protrusions and shorter distances between differentiating neurons. The experimental data and a theoretical model support the proposal that neuronal differentiation pattern is regulated by transient basal protrusions that deliver temporally controlled lateral inhibition mediated at a distance. This work uncovers a stereotyped protrusive activity of newborn neurons that organize long-distance spatiotemporal patterning of differentiation.


Subject(s)
Body Patterning , Cell Differentiation , Embryo, Nonmammalian/cytology , Laminin/metabolism , Motor Neurons/cytology , Spinal Cord/cytology , Zebrafish/embryology , Animals , Cell Communication , Embryo, Nonmammalian/metabolism , Gene Expression Regulation, Developmental , Intracellular Signaling Peptides and Proteins/genetics , Intracellular Signaling Peptides and Proteins/metabolism , Laminin/genetics , Membrane Proteins/genetics , Membrane Proteins/metabolism , Motor Neurons/metabolism , Neurogenesis , Signal Transduction , Spatio-Temporal Analysis , Spinal Cord/metabolism , Zebrafish/metabolism , Zebrafish Proteins/genetics , Zebrafish Proteins/metabolism
5.
Sci Rep ; 9(1): 7699, 2019 May 17.
Article in English | MEDLINE | ID: mdl-31097745

ABSTRACT

A correction to this article has been published and is linked from the HTML and PDF versions of this paper. The error has been fixed in the paper.

6.
Sci Rep ; 9(1): 1835, 2019 02 12.
Article in English | MEDLINE | ID: mdl-30755665

ABSTRACT

Tissue internalisation is a key morphogenetic mechanism by which embryonic tissues generate complex internal organs and a number of studies of epithelia have outlined a general view of tissue internalisation. Here we have used quantitative live imaging and mutant analysis to determine whether similar mechanisms are responsible for internalisation in a tissue that apparently does not have a typical epithelial organisation - the zebrafish neural plate. We found that although zebrafish embryos begin neurulation without a conventional epithelium, medially located neural plate cells adopt strategies typical of epithelia in order to constrict their dorsal surface membrane during cell internalisation. Furthermore, we show that Myosin-II activity is a significant driver of this transient cell remodeling which also depends on Cdh2 (N-cadherin). Abrogation of Cdh2 results in defective Myosin-II distribution, mislocalised internalisation events and defective neural plate morphogenesis. Our work suggests Cdh2 coordinates Myosin-II dependent internalisation of the zebrafish neural plate.


Subject(s)
Cadherins/metabolism , Gene Expression Regulation , Myosin Type II/metabolism , Neural Crest/embryology , Zebrafish Proteins/metabolism , Actins/metabolism , Animals , Animals, Genetically Modified , Body Patterning , Cell Membrane/metabolism , Cell Movement , Epithelium/embryology , Gene Expression Regulation, Developmental , Green Fluorescent Proteins/metabolism , Heterocyclic Compounds, 4 or More Rings/pharmacology , Microscopy, Confocal , Morphogenesis , Myosins/metabolism , Neural Plate/embryology , Oligonucleotides/pharmacology , Prospective Studies , Zebrafish/embryology
7.
Sci Rep ; 8(1): 17460, 2018 11 29.
Article in English | MEDLINE | ID: mdl-30498245

ABSTRACT

Carbonate depositional systems related to groundwater upwelling are ubiquitous around the world and form ecologically and culturally important features of many landscapes. Spring carbonate deposits record past climatic and hydrological conditions. The reconstruction of past processes using spring carbonate proxies requires fundamental understanding of the factors that control their geometry. In this work, we show that the spatial extent of spring carbonate platforms is amenable to quantitative prediction by simulating the early growth stage of their formation for the iconic mound springs in the central Australian outback. We exploit their well-defined, circular geometry to demonstrate the existence of two size-limiting regimes: one controlled by the spring flow rate and the other by the concentration of lattice ions. Deviations between modelled and observed size metrics are attributable to diminishing spring flow rates since formation, enabling assessment of the relative vulnerability of springs to further hydrological change.

8.
Dev Dyn ; 245(5): 580-9, 2016 05.
Article in English | MEDLINE | ID: mdl-26933766

ABSTRACT

BACKGROUND: During the initial stages zebrafish neurulation, neural plate cells undergo highly coordinated movements before they assemble into a multicellular solid neural rod. We have previously identified that the underlying mesoderm is critical to ensure such coordination and generate correct neural tube organization. However, how intertissue coordination is achieved in vivo during zebrafish neural tube morphogenesis is unknown. RESULTS: In this work, we use quantitative live imaging to study the coordinated movements of neural ectoderm and mesoderm during dorsal tissue convergence. We show the extracellular matrix components laminin and fibronectin that lie between mesoderm and neural plate act to couple the movements of neural plate and mesoderm during early stages of neurulation and to maintain the close apposition of these two tissues. CONCLUSIONS: Our study highlights the importance of the extracellular matrix proteins laminin and libronectin in coupling the movements and spatial proximity of mesoderm and neuroectoderm during the morphogenetic movements of neurulation. Developmental Dynamics 245:580-589, 2016. © 2016 Wiley Periodicals, Inc.


Subject(s)
Extracellular Matrix/physiology , Mesoderm/metabolism , Neural Plate/metabolism , Neurulation , Animals , Embryo, Nonmammalian , Fibronectins/physiology , Laminin/physiology , Morphogenesis , Neural Tube , Zebrafish
9.
Dev Cell ; 36(1): 117-126, 2016 Jan 11.
Article in English | MEDLINE | ID: mdl-26766447

ABSTRACT

We demonstrate the utility of the phytochrome system to rapidly and reversibly recruit proteins to specific subcellular regions within specific cells in a living vertebrate embryo. Light-induced heterodimerization using the phytochrome system has previously been used as a powerful tool to dissect signaling pathways for single cells in culture but has not previously been used to reversibly manipulate the precise subcellular location of proteins in multicellular organisms. Here we report the experimental conditions necessary to use this system to manipulate proteins in vivo. As proof of principle, we demonstrate that we can manipulate the localization of the apical polarity protein Pard3 with high temporal and spatial precision in both the neural tube and the embryo's enveloping layer epithelium. Our optimizations of optogenetic component expression and chromophore purification and delivery should significantly lower the barrier for establishing this powerful optogenetic system in other multicellular organisms.


Subject(s)
Optogenetics , Signal Transduction/physiology , Zebrafish/metabolism , Animals , Light , Protein Transport , Zebrafish/embryology , Zebrafish/genetics
10.
Neural Dev ; 8: 5, 2013 Mar 24.
Article in English | MEDLINE | ID: mdl-23521850

ABSTRACT

BACKGROUND: Morphogenesis requires developmental processes to occur both at the right time and in the right place. During neural tube formation in the zebrafish embryo, the generation of the apical specializations of the lumen must occur in the center of the neural rod after the neural cells have undergone convergence, invagination and interdigitation across the midline. How this coordination is achieved is uncertain. One possibility is that environmental signaling at the midline of the neural rod controls the schedule of apical polarization. Alternatively, polarization could be regulated by a timing mechanism and then independent morphogenetic processes ensure the cells are in the correct spatial location. RESULTS: Ectopic transplantation demonstrates the local environment of the neural midline is not required for neural cell polarization. Neural cells can self-organize into epithelial cysts in ectopic locations in the embryo and also in three-dimensional gel cultures. Heterochronic transplants demonstrate that the schedule of polarization and the specialized cell divisions characteristic of the neural rod are more strongly regulated by time than local environmental signals. The cells' schedule for polarization is set prior to gastrulation, is stable through several rounds of cell division and appears independent of the morphogenetic movements of gastrulation and neurulation. CONCLUSIONS: Time rather than local environment regulates the schedule of epithelial polarization in zebrafish neural rod.


Subject(s)
Body Patterning/physiology , Neural Stem Cells/cytology , Neural Tube/embryology , Neurogenesis/physiology , Zebrafish/embryology , Animals , Immunohistochemistry , Microscopy, Confocal
11.
Acta Otolaryngol ; 133(6): 590-3, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23379759

ABSTRACT

CONCLUSIONS: Combined approach tympanoplasty (CAT) allows for successful treatment of cholesteatoma with rates of recurrent and residual disease comparable to open mastoid surgery. Early timing of second-look procedures allows easier removal of any recurrent or residual disease, which reduces the conversion rate to open mastoidectomy. OBJECTIVES: The aims of the study were to report the rates of recurrent and residual cholesteatoma following primary CAT surgery and to report the rate of conversion to a modified radical mastoidectomy. METHODS: This was a retrospective review of a single surgeon series between 2006 and 2012. RESULTS: In total 132 second-look operations were undertaken, with a mean interval between primary surgery and second-look procedures of 6 months. The rate of cholesteatoma at second-look surgery was 19.7%, which was split into residual disease (10.6%) and recurrent disease (9.09%). New tympanic membrane defects with cholesteatoma were considered as recurrent disease. Residual disease was defined as cholesteatoma present behind an intact tympanic membrane. The majority of recurrent and residual disease was easily removed at second look (73.1%). Only four cases were converted to a modified radical mastoidectomy (3%) and three cases required a third-look procedure.


Subject(s)
Cholesteatoma, Middle Ear/surgery , Tympanoplasty , Adolescent , Adult , Child , Child, Preschool , Cholesteatoma, Middle Ear/diagnosis , Humans , Middle Aged , Recurrence , Retrospective Studies , Second-Look Surgery , Treatment Outcome , Young Adult
12.
EMBO J ; 32(1): 30-44, 2013 Jan 09.
Article in English | MEDLINE | ID: mdl-23202854

ABSTRACT

By analysing the cellular and subcellular events that occur in the centre of the developing zebrafish neural rod, we have uncovered a novel mechanism of cell polarisation during lumen formation. Cells from each side of the neural rod interdigitate across the tissue midline. This is necessary for localisation of apical junctional proteins to the region where cells intersect the tissue midline. Cells assemble a mirror-symmetric microtubule cytoskeleton around the tissue midline, which is necessary for the trafficking of proteins required for normal lumen formation, such as partitioning defective 3 and Rab11a to this point. This occurs in advance and is independent of the midline cell division that has been shown to have a powerful role in lumen organisation. To our knowledge, this is the first example of the initiation of apical polarisation part way along the length of a cell, rather than at a cell extremity. Although the midline division is not necessary for apical polarisation, it confers a morphogenetic advantage by efficiently eliminating cellular processes that would otherwise bridge the developing lumen.


Subject(s)
Cell Communication , Microtubules/metabolism , Neural Tube/embryology , Neurulation , Zebrafish Proteins/metabolism , Zebrafish/embryology , Animals , Body Patterning , Carrier Proteins/genetics , Carrier Proteins/metabolism , Cell Division , Cell Movement , Cell Polarity , Embryo, Nonmammalian/cytology , Embryo, Nonmammalian/embryology , Green Fluorescent Proteins/chemistry , Luminescent Agents/chemistry , Microtubules/genetics , Mutation , Neural Tube/cytology , Nocodazole/pharmacology , Protein Transport/drug effects , Recombinant Fusion Proteins , Tubulin Modulators/pharmacology , Zebrafish/anatomy & histology , Zebrafish/genetics , Zebrafish/metabolism , Zebrafish Proteins/genetics , rab GTP-Binding Proteins/genetics , rab GTP-Binding Proteins/metabolism
13.
Neural Dev ; 7: 32, 2012 Sep 18.
Article in English | MEDLINE | ID: mdl-22989074

ABSTRACT

BACKGROUND: Although the mechanisms underlying brain patterning and regionalization are very much conserved, the morphology of different brain regions is extraordinarily variable across vertebrate phylogeny. This is especially manifest in the telencephalon, where the most dramatic variation is seen between ray-finned fish, which have an everted telencephalon, and all other vertebrates, which have an evaginated telencephalon. The mechanisms that generate these distinct morphologies are not well understood. RESULTS: Here we study the morphogenesis of the zebrafish telencephalon from 12 hours post fertilization (hpf) to 5 days post fertilization (dpf) by analyzing forebrain ventricle formation, evolving patterns of gene and transgene expression, neuronal organization, and fate mapping. Our results highlight two key events in telencephalon morphogenesis. First, the formation of a deep ventricular recess between telencephalon and diencephalon, the anterior intraencephalic sulcus (AIS), effectively creates a posterior ventricular wall to the telencephalic lobes. This process displaces the most posterior neuroepithelial territory of the telencephalon laterally. Second, as telencephalic growth and neurogenesis proceed between days 2 and 5 of development, the pallial region of the posterior ventricular wall of the telencephalon bulges into the dorsal aspect of the AIS. This brings the ventricular zone (VZ) into close apposition with the roof of the AIS to generate a narrow ventricular space and the thin tela choroidea (tc). As the pallial VZ expands, the tc also expands over the upper surface of the telencephalon. During this period, the major axis of growth and extension of the pallial VZ is along the anteroposterior axis. This second step effectively generates an everted telencephalon by 5 dpf. CONCLUSION: Our description of telencephalic morphogenesis challenges the conventional model that eversion is simply due to a laterally directed outfolding of the telencephalic neuroepithelium. This may have significant bearing on understanding the eventual organization of the adult fish telencephalon.


Subject(s)
Morphogenesis/physiology , Neurons/physiology , Telencephalon , Zebrafish/anatomy & histology , Animals , Animals, Genetically Modified , Body Patterning/genetics , Body Patterning/physiology , Brain Mapping , Bromodeoxyuridine/metabolism , Embryo, Nonmammalian , Green Fluorescent Proteins/genetics , Microscopy, Confocal , Morphogenesis/genetics , Neural Pathways/embryology , Neural Pathways/growth & development , Neural Pathways/metabolism , Neuropil/physiology , RNA, Messenger/administration & dosage , Telencephalon/cytology , Telencephalon/embryology , Telencephalon/growth & development , Time Factors , Zebrafish/embryology , Zebrafish/growth & development , Zebrafish Proteins/genetics
14.
Astrobiology ; 11(10): 1017-33, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22149914

ABSTRACT

We present a comprehensive model of martian pressure-temperature (P-T) phase space and compare it with that of Earth. Martian P-T conditions compatible with liquid water extend to a depth of ∼310 km. We use our phase space model of Mars and of terrestrial life to estimate the depths and extent of the water on Mars that is habitable for terrestrial life. We find an extensive overlap between inhabited terrestrial phase space and martian phase space. The lower martian surface temperatures and shallower martian geotherm suggest that, if there is a hot deep biosphere on Mars, it could extend 7 times deeper than the ∼5 km depth of the hot deep terrestrial biosphere in the crust inhabited by hyperthermophilic chemolithotrophs. This corresponds to ∼3.2% of the volume of present-day Mars being potentially habitable for terrestrial-like life.


Subject(s)
Mars , Models, Theoretical , Pressure , Temperature , Water , Soil
15.
Nat Neurosci ; 13(6): 673-9, 2010 Jun.
Article in English | MEDLINE | ID: mdl-20453852

ABSTRACT

In the developing CNS, asymmetric cell division is critical for maintaining the balanced production of differentiating neurons while renewing the population of neural progenitors. In invertebrates, this process depends on asymmetric inheritance of fate determinants during progenitor divisions. A similar mechanism is widely believed to underlie asymmetrically fated divisions in vertebrates, but compelling evidence for this is missing. We used live imaging of individual progenitors in the intact zebrafish embryo CNS to test this hypothesis. We found that asymmetric inheritance of a subcellular domain is strongly correlated with asymmetric daughter fates and our results reveal an unexpected feature of this process. The daughter cell destined to become a neuron was derived from the more apical of the two daughters, whereas the more basal daughter inherited the basal process and replenished the apical progenitor pool.


Subject(s)
Neural Tube/embryology , Neural Tube/physiology , Neurogenesis/physiology , Neurons/physiology , Stem Cells/physiology , Animals , Cell Division/physiology , Immunohistochemistry , Microscopy, Confocal/methods , Neural Tube/anatomy & histology , Protein Kinase C/metabolism , Rhombencephalon/anatomy & histology , Rhombencephalon/embryology , Rhombencephalon/physiology , Time Factors , Video Recording , Zebrafish
16.
Methods Mol Biol ; 546: 145-51, 2009.
Article in English | MEDLINE | ID: mdl-19378103

ABSTRACT

A method is described that allows the introduction by electroporation of either small dyes or larger RNA, DNA, or morpholino constructs into single cells or small groups of cells in zebrafish embryos or larvae. The dye or construct is delivered to cells via a patch-like microelectrode that also delivers the electroporation stimulus train. This technique allows the experimenter to target cells of their choice at a particular time of development and at a particular location in the embryo, and is useful for fate mapping, analysing neuronal organisation, ectopic expression and gene knockdown experiments.


Subject(s)
Developmental Biology/methods , Electroporation/methods , Zebrafish/embryology , Zebrafish/genetics , Animals , Animals, Genetically Modified/embryology , Animals, Genetically Modified/genetics , Animals, Genetically Modified/metabolism , DNA/genetics , DNA/metabolism , Embryo, Nonmammalian/cytology , Embryo, Nonmammalian/drug effects , Fluorescent Dyes/pharmacology , Larva/cytology , Larva/drug effects , Microscopy , RNA/genetics , RNA/metabolism , Rhodamines/pharmacology , Time Factors , Zebrafish/metabolism
18.
Biomed Mater ; 3(1): 011001, 2008 Mar.
Article in English | MEDLINE | ID: mdl-18458487

ABSTRACT

Bio-electrosprays are rapidly emerging as a viable protocol for directly engineering living cells. This communication reports the bio-electrospraying of multicellular organisms, namely zebrafish embryos. The results demonstrate that the bio-electrospray protocol fails to induce any embryological perturbations. In addition to analysing overall embryo morphology, we use transgenic embryos that express green fluorescent protein in specific brain neurons to determine that neuronal numbers and organization are completely normal. These results demonstrate that the bio-electrospraying protocol does not interfere with the complex gene regulation and cell movements required for the development of a multicellular organism.


Subject(s)
Electrochemistry/methods , Embryo, Nonmammalian/physiology , Embryonic Development/physiology , Microfluidics/methods , Organ Culture Techniques/methods , Zebrafish/embryology , Zebrafish/physiology , Animals , Cell Survival , Embryo, Nonmammalian/cytology , Fetal Viability/physiology , Pressure , Tissue Engineering/methods , Zebrafish/anatomy & histology
19.
Neural Dev ; 3: 9, 2008 Mar 31.
Article in English | MEDLINE | ID: mdl-18377638

ABSTRACT

BACKGROUND: Functional lateralization is a conserved feature of the central nervous system (CNS). However, underlying left-right asymmetries within neural circuitry and the mechanisms by which they develop are poorly described. RESULTS: In this study, we use focal electroporation to examine the morphology and connectivity of individual neurons of the lateralized habenular nuclei. Habenular projection neurons on both sides of the brain share a stereotypical unipolar morphology and elaborate remarkable spiraling terminal arbors in their target interpeduncular nucleus, a morphology unlike that of any other class of neuron described to date. There are two quite distinct sub-types of axon arbor that differ both in branching morphology and in their localization within the target nucleus. Critically, both arbor morphologies are elaborated by both left and right-sided neurons, but at greatly differing frequencies. We show that these differences in cell type composition account for the gross connectional asymmetry displayed by the left and right habenulae. Analysis of the morphology and projections of individual post-synaptic neurons suggests that the target nucleus has the capacity to either integrate left and right inputs or to handle them independently, potentially relaying information from the left and right habenulae within distinct downstream pathways, thus preserving left-right coding. Furthermore, we find that signaling from the unilateral, left-sided parapineal nucleus is necessary for both left and right axons to develop arbors with appropriate morphology and targeting. However, following parapineal ablation, left and right habenular neurons continue to elaborate arbors with distinct, lateralized morphologies. CONCLUSION: By taking the analysis of asymmetric neural circuitry to the level of single cells, we have resolved left-right differences in circuit microarchitecture and show that lateralization can be recognized at the level of the morphology and connectivity of single projection neuron axons. Crucially, the same circuitry components are specified on both sides of the brain, but differences in the ratios of different neuronal sub-types results in a lateralized neural architecture and gross connectional asymmetry. Although signaling from the parapineal is essential for the development of normal lateralization, additional factors clearly act during development to confer left-right identity upon neurons in this highly conserved circuit.


Subject(s)
Functional Laterality/physiology , Habenula/cytology , Habenula/embryology , Presynaptic Terminals/physiology , Zebrafish/embryology , Animals , Axons/physiology , Green Fluorescent Proteins/genetics , Neural Pathways/cytology , Neural Pathways/embryology
20.
Nature ; 446(7137): 797-800, 2007 Apr 12.
Article in English | MEDLINE | ID: mdl-17392791

ABSTRACT

The development of cell polarity is an essential prerequisite for tissue morphogenesis during embryogenesis, particularly in the development of epithelia. In addition, oriented cell division can have a powerful influence on tissue morphogenesis. Here we identify a novel mode of polarized cell division that generates pairs of neural progenitors with mirror-symmetric polarity in the developing zebrafish neural tube and has dramatic consequences for the organization of embryonic tissue. We show that during neural rod formation the polarity protein Pard3 is localized to the cleavage furrow of dividing progenitors, and then mirror-symmetrically inherited by the two daughter cells. This allows the daughter cells to integrate into opposite sides of the developing neural tube. Furthermore, these mirror-symmetric divisions have powerful morphogenetic influence: when forced to occur in ectopic locations during neurulation, they orchestrate the development of mirror-image pattern formation and the consequent generation of ectopic neural tubes.


Subject(s)
Body Patterning , Cell Polarity , Epithelial Cells/cytology , Nervous System/cytology , Nervous System/embryology , Neurons/cytology , Zebrafish/embryology , Animals , Carrier Proteins/metabolism , Cell Division , Embryo, Nonmammalian/cytology , Embryo, Nonmammalian/embryology , Zebrafish Proteins/metabolism
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