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We demonstrate that in the zebrafish hindbrain, cell shape, rhombomere morphogenesis and, unexpectedly, brain ventricle lumen expansion depend on the contractile state of the neuroepithelium. The hindbrain neural tube opens in a specific sequence, with initial separation along the midline at rhombomere boundaries, subsequent openings within rhombomeres and eventual coalescence of openings into the hindbrain ventricle lumen. A mutation in the myosin phosphatase regulator mypt1 results in a small ventricle due to impaired stretching of the surrounding neuroepithelium. Although initial hindbrain opening remains normal, mypt1 mutant rhombomeres do not undergo normal morphological progression. Three-dimensional reconstruction demonstrates cell shapes within rhombomeres and at rhombomere boundaries are abnormal in mypt1 mutants. Wild-type cell shape requires that surrounding cells are also wild type, whereas mutant cell shape is autonomously regulated. Supporting the requirement for regulation of myosin function during hindbrain morphogenesis, wild-type embryos show dynamic levels of phosphorylated myosin regulatory light chain (pMRLC). By contrast, mutants show continuously high pMRLC levels, with concentration of pMRLC and myosin II at the apical side of the epithelium, and myosin II and actin concentration at rhombomere boundaries. Brain ventricle lumen expansion, rhombomere morphology and cell shape are rescued by inhibition of myosin II function, indicating that each defect is a consequence of overactive myosin. We suggest that the epithelium must ;relax', via activity of myosin phosphatase, to allow for normal hindbrain morphogenesis and expansion of the brain ventricular lumen. Epithelial relaxation might be a widespread strategy to facilitate tube inflation in many organs.
Amsterdam,
Identification of 315 genes essential for early zebrafish development.
2004, Pubmed
Amsterdam,
Identification of 315 genes essential for early zebrafish development.
2004,
Pubmed
Camello-Almaraz,
Developmental changes in Ca2+ homeostasis and contractility in gallbladder smooth muscle.
2009,
Pubmed
Clark,
Myosin II and mechanotransduction: a balancing act.
2007,
Pubmed
Cooke,
EphA4 is required for cell adhesion and rhombomere-boundary formation in the zebrafish.
2005,
Pubmed
Ding,
Signaling processes for initiating smooth muscle contraction upon neural stimulation.
2009,
Pubmed
Escudero,
Myosin II regulates complex cellular arrangement and epithelial architecture in Drosophila.
2007,
Pubmed
Eto,
Assembly of MYPT1 with protein phosphatase-1 in fibroblasts redirects localization and reorganizes the actin cytoskeleton.
2005,
Pubmed
Gato,
Why the embryo still matters: CSF and the neuroepithelium as interdependent regulators of embryonic brain growth, morphogenesis and histiogenesis.
2009,
Pubmed
Gutzman,
Formation of the zebrafish midbrain-hindbrain boundary constriction requires laminin-dependent basal constriction.
2008,
Pubmed
Gutzman,
Zebrafish brain ventricle injection.
2009,
Pubmed
Hanneman,
Segmental pattern of development of the hindbrain and spinal cord of the zebrafish embryo.
1988,
Pubmed
Hartshorne,
Role of protein phosphatase type 1 in contractile functions: myosin phosphatase.
2004,
Pubmed
Heyman,
Cellular morphology and extracellular space at rhombomere boundaries in the chick embryo hindbrain.
1993,
Pubmed
Hildebrand,
Shroom regulates epithelial cell shape via the apical positioning of an actomyosin network.
2005,
Pubmed
Hirano,
Current topics in the regulatory mechanism underlying the Ca2+ sensitization of the contractile apparatus in vascular smooth muscle.
2007,
Pubmed
Huang,
Signaling pathways mediating gastrointestinal smooth muscle contraction and MLC20 phosphorylation by motilin receptors.
2005,
Pubmed
Huang,
Mypt1-mediated spatial positioning of Bmp2-producing cells is essential for liver organogenesis.
2008,
Pubmed
Ihara,
Characterization of protein kinase pathways responsible for Ca2+ sensitization in rat ileal longitudinal smooth muscle.
2007,
Pubmed
Ito,
Myosin phosphatase: structure, regulation and function.
2004,
Pubmed
Kawano,
Phosphorylation of myosin-binding subunit (MBS) of myosin phosphatase by Rho-kinase in vivo.
1999,
Pubmed
Kimmel,
Stages of embryonic development of the zebrafish.
1995,
Pubmed
,
Xenbase
Kinoshita,
Apical accumulation of Rho in the neural plate is important for neural plate cell shape change and neural tube formation.
2008,
Pubmed
,
Xenbase
Kovács,
Mechanism of blebbistatin inhibition of myosin II.
2004,
Pubmed
Landsverk,
Genetic analysis of myosin II assembly and organization in model organisms.
2005,
Pubmed
Lecuit,
Cell surface mechanics and the control of cell shape, tissue patterns and morphogenesis.
2007,
Pubmed
Lee,
Excessive Myosin activity in mbs mutants causes photoreceptor movement out of the Drosophila eye disc epithelium.
2004,
Pubmed
Lowery,
Initial formation of zebrafish brain ventricles occurs independently of circulation and requires the nagie oko and snakehead/atp1a1a.1 gene products.
2005,
Pubmed
Lowery,
Totally tubular: the mystery behind function and origin of the brain ventricular system.
2009,
Pubmed
,
Xenbase
Lowery,
Characterization and classification of zebrafish brain morphology mutants.
2009,
Pubmed
Lumsden,
Segmentation and compartition in the early avian hindbrain.
2004,
Pubmed
Matsumura,
Myosin phosphatase target subunit: Many roles in cell function.
2008,
Pubmed
Maves,
FGF3 and FGF8 mediate a rhombomere 4 signaling activity in the zebrafish hindbrain.
2002,
Pubmed
McCray,
Developing bronchopulmonary epithelium of the human fetus secretes fluid.
1992,
Pubmed
Mizuno,
Drosophila myosin phosphatase and its role in dorsal closure.
2002,
Pubmed
Moens,
Constructing the hindbrain: insights from the zebrafish.
2002,
Pubmed
Pfitzer,
Invited review: regulation of myosin phosphorylation in smooth muscle.
2001,
Pubmed
Poley,
Stimulated calcium entry and constitutive RhoA kinase activity cause stretch-induced detrusor contraction.
2008,
Pubmed
Quintin,
Epithelial morphogenesis in embryos: asymmetries, motors and brakes.
2008,
Pubmed
Rolo,
Morphogenetic movements driving neural tube closure in Xenopus require myosin IIB.
2009,
Pubmed
,
Xenbase
Tan,
Roles of myosin phosphatase during Drosophila development.
2003,
Pubmed
Vaage,
The segmentation of the primitive neural tube in chick embryos (Gallus domesticus). A morphological, histochemical and autoradiographical investigation.
1969,
Pubmed
Weiser,
Rho-regulated myosin phosphatase establishes the level of protrusive activity required for cell movements during zebrafish gastrulation.
2009,
Pubmed
Woo,
Order and coherence in the fate map of the zebrafish nervous system.
1995,
Pubmed
