Article

Essential roles of G 12/13 signaling in distinct cell behaviors driving zebrafish convergence and extension gastrulation movements

Department of Pharmacology, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
The Journal of Cell Biology (Impact Factor: 9.69). 07/2005; 169(5):777-87. DOI: 10.1083/jcb.200501104
Source: PubMed

ABSTRACT Galpha(12/13) have been implicated in numerous cellular processes, however, their roles in vertebrate gastrulation are largely unknown. Here, we show that during zebrafish gastrulation, suppression of both Galpha(12) and Galpha(13) signaling by overexpressing dominant negative proteins and application of antisense morpholino-modified oligonucleotide translation interference disrupted convergence and extension without changing embryonic patterning. Analyses of mesodermal cell behaviors revealed that Galpha(12/13) are required for cell elongation and efficient dorsalward migration during convergence independent of noncanonical Wnt signaling. Furthermore, Galpha(12/13) function cell-autonomously to mediate mediolateral cell elongation underlying intercalation during notochord extension, likely acting in parallel to noncanonical Wnt signaling. These findings provide the first evidence that Galpha(12) and Galpha(13) have overlapping and essential roles in distinct cell behaviors that drive vertebrate gastrulation.

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Available from: Fang Lin, Aug 25, 2015
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    • "2516 RESEARCH ARTICLE Development (2015) 142, 2508-2520 doi:10.1242/dev.119032 DEVELOPMENT Gα 12/13 acting in a cell-autonomous manner and likely in parallel to Wnt/PCP (Lin et al., 2005), and Rok2 affecting cell shape cellautonomously but ML cell alignment in a non-cell-autonomous manner acting downstream of Wnt/PCP (Lin et al., 2005; Marlow et al., 2002). Although a link between the cytoskeleton and Wnt/PCP has been established, stage/domain-specific signals instructing such cytoskeletal regulators remain to be clarified. "
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    ABSTRACT: During vertebrate gastrulation, convergence and extension movements elongate embryonic tissues anteroposteriorly and narrow them mediolaterally. Planar Cell Polarity (PCP) signaling is essential for mediolateral cell elongation underlying these movements, but how this polarity arises is poorly understood. We analyzed cell elongation, orientation, and migration behaviors of lateral mesodermal cells undergoing convergence and extension movements in wild-type embryos and mutants for the Wnt/PCP core component Trilobite/Vangl2. We demonstrate that Vangl2 function is required at the time when cells transition to a highly elongated and mediolaterally aligned body. We show that tri/vangl2 mutant cells fail to undergo this transition and to migrate along a straight path and high net speed towards the dorsal midline. Instead, tri/vangl2 mutant cells exhibit an anterior/animal pole bias in their cell body alignment and movement direction, suggesting that PCP signaling promotes effective dorsal migration in part by suppressing anterior/animalward cell polarity and movement. Endogenous Vangl2 protein accumulates at the plasma membrane of mesenchymal converging cells at the time its function is required for mediolaterally polarized cell behavior. Heterochronic cell transplantations demonstrated that Vangl2 cell membrane accumulation is stage dependent, and regulated by both intrinsic factors and an extracellular signal, which is distinct from PCP signaling or other gastrulation regulators, including BMP and Nodals. Moreover, mosaic expression of fusion proteins revealed enrichment of Vangl2 at the anterior cell edges of highly mediolaterally elongated cells, consistent with the PCP pathway core components' asymmetric distribution in Drosophila and vertebrate epithelia. © 2015. Published by The Company of Biologists Ltd.
    Development 06/2015; 142(14). DOI:10.1242/dev.119032 · 6.27 Impact Factor
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    • "Vertebrate gastrulation relies on polarized cell behaviors to drive convergence and extension (C&E) movements that narrow embryonic tissues mediolaterally and elongate them anteroposteriorly (Keller et al., 2000; Solnica-Krezel, 2005; Yin et al., 2009; Gray et al., 2011). In dorsal regions of Xenopus and zebrafish gastrulae, cells become elongated and align along the mediolateral embryonic axis, allowing preferential intercalation between their anterior and posterior neighbors to drive C&E (Keller et al., 2000; Topczewski et al., 2001; Jessen et al., 2002; Marlow et al., 2002; Lin et al., 2005). Modulation of cell adhesion and intercellular signaling have been proposed to instruct such complex cell behaviors (Yin et al., 2009). "
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    ABSTRACT: During vertebrate gastrulation, Wnt/planar cell polarity (PCP) signaling orchestrates polarized cell behaviors underlying convergence and extension (C&E) movements to narrow embryonic tissues mediolaterally and lengthen them anteroposteriorly. Here, we have identified Gpr125, an adhesion G protein-coupled receptor, as a novel modulator of the Wnt/PCP signaling system. Excess Gpr125 impaired C&E movements and the underlying cell and molecular polarities. Reduced Gpr125 function exacerbated the C&E and facial branchiomotor neuron (FBMN) migration defects of embryos with reduced Wnt/PCP signaling. At the molecular level, Gpr125 recruited Dishevelled to the cell membrane, a prerequisite for Wnt/PCP activation. Moreover, Gpr125 and Dvl mutually clustered one another to form discrete membrane subdomains, and the Gpr125 intracellular domain directly interacted with Dvl in pull-down assays. Intriguingly, Dvl and Gpr125 were able to recruit a subset of PCP components into membrane subdomains, suggesting that Gpr125 may modulate the composition of Wnt/PCP membrane complexes. Our study reveals a role for Gpr125 in PCP-mediated processes and provides mechanistic insight into Wnt/PCP signaling.
    Development 07/2013; 140(14):3028-3039. DOI:10.1242/dev.094839 · 6.27 Impact Factor
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    • "S1pr2 overexpression induced defects in convergence and extension (C&E) movements (revealed by broadening of the axial mesoderm, Fig. 3A versus 3B, red lines), as well as in epiboly [evident from increase in the distance between the deep-cell margin (dcm) and the vegetal pole (VP), Fig. 3A versus 3B, blue lines with double arrows]. At 35 hpf, these embryos displayed a shortened body axis and frequently also cyclopia (Fig. 3D), phenotypes often associated with impaired C&E movements (Heisenberg et al., 2000; Jessen et al., 2002; Lin et al., 2005). Remarkably, the gastrulation defects induced by S1pr2 overexpression were largely suppressed by Ga 13 inhibition, as judged by morphological observation and analysis of ntl expression (Fig. 3C,F). "
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    ABSTRACT: A key process during vertebrate heart development is the migration of bilateral populations of myocardial precursors towards the midline to form the primitive heart tube. In zebrafish, signaling mediated by sphingosine-1-phosphate (S1P) and its cognate G protein-coupled receptor (S1pr2/Mil) is essential for myocardial migration, but the underlying mechanisms remain undefined. Here, we show that suppression of Gα(13) signaling disrupts myocardial migration, leading to the formation of two bilaterally located hearts (cardia bifida). Genetic studies indicate that Gα(13) acts downstream of S1pr2 to regulate myocardial migration through a RhoGEF-dependent pathway. Furthermore, disrupting any component of the S1pr2/Gα(13)/RhoGEF pathway impairs endoderm convergence during segmentation, and the endodermal defects correlate with the extent of cardia bifida. Moreover, endoderm transplantation reveals that the presence of wild-type anterior endodermal cells in Gα(13)-deficient embryos is sufficient to rescue the endoderm convergence defect and cardia bifida, and, conversely, that the presence of anterior endodermal cells defective for S1pr2 or Gα(13) in wild-type embryos causes such defects. Thus, S1pr2/Gα(13) signaling probably acts in the endoderm to regulate myocardial migration. In support of this notion, cardiac-specific expression of Gα(13) fails to rescue cardia bifida in the context of global Gα(13) inhibition. Our data demonstrate for the first time that the Gα(13)/RhoGEF-dependent pathway functions downstream of S1pr2 to regulate convergent movement of the endoderm, an event that is crucial for coordinating myocardial migration.
    Development 01/2013; 140(4). DOI:10.1242/dev.085340 · 6.27 Impact Factor
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