Do lamellipodia have the mechanical capacity to drive convergent extension?

Brodland, G. Wayne

doi:10.1387/ijdb.052040gb

Cited by 41 publications

(46 citation statements)

References 37 publications

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“…While the cellular behavior and the driving force for radial intercalation is unclear, it is known that during mediolateral intercalation, cells are polarized or elongated along mediolateral axis and project mediolaterally oriented lamellapodia Keller, 1991, Keller, 2002). Computational models suggest that force generated by the protrusive activity of the cells along the mediolateral axis is sufficient to drive the intercalation of cells along the same axis (Zajac et al, 2003, Brodland, 2006, Brodland and Veldhuis, 2006. This hypothesis is consistent with the observation that actin-myosin cytoskeletal components are required for cellular intercalation (Zallen and Wieschaus, 2004).…”

Section: Convergent Extension In the Developing Organ Of Cortisupporting

confidence: 79%

Shaping the mammalian auditory sensory organ by the planar cell polarity pathway

Kelly

Chen

2007

Int. J. Dev. Biol.

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The human ear is capable of processing sound with a remarkable resolution over a wide range of intensity and frequency. This ability depends largely on the extraordinary feats of the hearing organ, the organ of Corti and its sensory hair cells. The organ of Corti consists of precisely patterned rows of sensory hair cells and supporting cells along the length of the snailshaped cochlear duct. On the apical surface of each hair cell, several rows of actin-containing protrusions, known as stereocilia, form a "V"-shaped staircase. The vertices of all the "V"-shaped stereocilia point away from the center of the cochlea. The uniform orientation of stereocilia in the organ of Corti manifests a distinctive form of polarity known as planar cell polarity (PCP). Functionally, the direction of stereociliary bundle deflection controls the mechanical channels located in the stereocilia for auditory transduction. In addition, hair cells are tonotopically organized along the length of the cochlea. Thus, the uniform orientation of stereociliary bundles along the length of the cochlea is critical for effective mechanotransduction and for frequency selection. Here we summarize the morphological and molecular events that bestow the structural characteristics of the mammalian hearing organ, the growth of the snail-shaped cochlear duct and the establishment of PCP in the organ of Corti. The PCP of the sensory organs in the vestibule of the inner ear will also be described briefly.

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Section: Convergent Extension In the Developing Organ Of Cortisupporting

confidence: 79%

Shaping the mammalian auditory sensory organ by the planar cell polarity pathway

Kelly

Chen

2007

Int. J. Dev. Biol.

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“…Computer simulations (Brodland 2006;Brodland and Veldhuis 2006) show that medio-laterally oriented cells would be expected in the neural plate because of the lamellipodium-driven convergent extension occurring there. Whether the mitosis orientations are a direct result of these cell geometries or are the consequence of morphogen gradients that trigger lamellipodium action (Keller et al 2000;Wallingford and Harland 2002;Keller 2006) is not yet clear.…”

Section: Results and Conclusionmentioning

confidence: 99%

Detection of mitoses in embryonic epithelia using motion field analysis

Siva¹,

Brodland²,

Clausi³

2009

Computer Methods in Biomechanics and Biomedical Engineering

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Although computer simulations indicate that mitosis may be important to the mechanics of morphogenetic movements, algorithms to identify mitoses in bright field images of embryonic epithelia have not previously been available. Here, the authors present an algorithm that identifies mitoses and their orientations based on the motion field between successive images. Within this motion field, the algorithm seeks 'mitosis motion field prototypes' characterised by convergent motion in one direction and divergent motion in the orthogonal direction, the local motions produced by the division process. The algorithm uses image processing, vector field analyses and pattern recognition to identify occurrences of this prototype and to determine its orientation. When applied to time-lapse images of gastrulation and neurulation-stage amphibian (Ambystoma mexicanum) embryos, the algorithm achieves identification accuracies of 68 and 67%, respectively and angular accuracies of the order of 308, values sufficient to assess the role of mitosis in these developmental processes.

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“…Deep and superficial cells elongated considerably as they established contact with both surfaces of the neuroepithelium. It is likely that the protrusive activity exhibited by both cell populations contributes to, and possibly drives, medial convergence and radial intercalation (Brodland, 2006). Because this mode of neurulation does not involve a folding process per se, but rather active en masse cell movement, the term convergence rather than infolding seems more appropriate.…”

Section: Cells Exhibit Polarized Protrusive Activity During Neurulationmentioning

confidence: 99%

N-cadherinis required for the polarized cell behaviors that drive neurulation in the zebrafish

2006

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Through the direct analysis of cell behaviors, we address the mechanisms underlying anterior neural tube morphogenesis in the zebrafish and the role of the cell adhesion molecule N-cadherin (N-cad) in this process. We demonstrate that although the mode of neurulation differs at the morphological level between amphibians and teleosts, the underlying cellular mechanisms are conserved. Contrary to previous reports, the zebrafish neural plate is a multi-layered structure, composed of deep and superficial cells that converge medially while undergoing radial intercalation, to form a single cell-layered neural tube. Time-lapse recording of individual cell behaviors reveals that cells are polarized along the mediolateral axis and exhibit protrusive activity. In N-cad mutants, both convergence and intercalation are blocked. Moreover, although N-cad-depleted cells are not defective in their ability to form protrusions, they are unable to maintain them stably. Taken together, these studies uncover key cellular mechanisms underlying neural tube morphogenesis in teleosts, and reveal a role for cadherins in promoting the polarized cell behaviors that underlie cellular rearrangements and shape the vertebrate embryo.

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Do lamellipodia have the mechanical capacity to drive convergent extension?

Cited by 41 publications

References 37 publications

Shaping the mammalian auditory sensory organ by the planar cell polarity pathway

Shaping the mammalian auditory sensory organ by the planar cell polarity pathway

Detection of mitoses in embryonic epithelia using motion field analysis

N-cadherinis required for the polarized cell behaviors that drive neurulation in the zebrafish

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