Abstract
Oriented mitosis is essential during tissue morphogenesis. The Wnt/planar cell polarity (Wnt/PCP) pathway orients mitosis in a number of developmental systems, including dorsal epiblast cell divisions along the animal-vegetal (A-V) axis during zebrafish gastrulation. How Wnt signalling orients the mitotic plane is, however, unknown. Here we show that, in dorsal epiblast cells, anthrax toxin receptor 2a (Antxr2a) accumulates in a polarized cortical cap, which is aligned with the embryonic A-V axis and forecasts the division plane. Filamentous actin (F-actin) also forms an A-V polarized cap, which depends on Wnt/PCP and its effectors RhoA and Rock2. Antxr2a is recruited to the cap by interacting with actin. Antxr2a also interacts with RhoA and together they activate the diaphanous-related formin zDia2. Mechanistically, Antxr2a functions as a Wnt-dependent polarized determinant, which, through the action of RhoA and zDia2, exerts torque on the spindle to align it with the A-V axis.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Actins / metabolism
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Animals
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Bacterial Proteins / biosynthesis
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Bacterial Proteins / genetics
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Carrier Proteins / metabolism
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Cell Membrane / metabolism
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Cell Polarity
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Cytoskeleton / metabolism
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Doublecortin Domain Proteins
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Embryo, Nonmammalian / cytology
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Formins
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Gene Knockdown Techniques
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Germ Layers / cytology
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Germ Layers / metabolism
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Luminescent Proteins / biosynthesis
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Luminescent Proteins / genetics
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Microtubule-Associated Proteins / metabolism
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Mitosis
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Monomeric GTP-Binding Proteins / metabolism
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Monomeric GTP-Binding Proteins / physiology
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Morpholinos / genetics
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Neuropeptides / metabolism
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Protein Transport
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Receptors, Peptide / genetics
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Receptors, Peptide / metabolism
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Receptors, Peptide / physiology*
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Recombinant Fusion Proteins / biosynthesis
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Recombinant Fusion Proteins / genetics
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Spindle Apparatus / metabolism*
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Time-Lapse Imaging
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Wnt Signaling Pathway
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Zebrafish
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Zebrafish Proteins / genetics
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Zebrafish Proteins / metabolism
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Zebrafish Proteins / physiology*
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rho-Associated Kinases / metabolism
Substances
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Actins
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Antxr2a protein, zebrafish
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Bacterial Proteins
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Carrier Proteins
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Doublecortin Domain Proteins
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Formins
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Luminescent Proteins
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Microtubule-Associated Proteins
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Morpholinos
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Neuropeptides
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Receptors, Peptide
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Recombinant Fusion Proteins
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Zebrafish Proteins
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diaph2 protein, zebrafish
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yellow fluorescent protein, Bacteria
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Rock2a protein, zebrafish
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rho-Associated Kinases
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Monomeric GTP-Binding Proteins
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rhoab protein, zebrafish