4-1-13_frogs_pt_3

826 deep cell movements dorsal dorsal imz imz ventral

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Unformatted text preview: al IMZ IMZ ventral anterior LEM ventral DIMZ LEM posterior Hd Ht LV Notice how much the cells of the dorsal IMZ elongate. LEM courtesy Ray Keller IMZ undergoes convergent extension Gilbert, 4e, Fig. 4.24 Fluorescently labeled cells mix with labeled cells Conclusion: The dorsal IMZ undergoes dramatic convergent extension Keller explants allow analysis of convergent extnesion Pieces of the early gastrula that include what would normally become neural ectoderm and axial mesoderm (notochord and somites) are excised. A practical issue: these are not happy on their own, so two of these are placed together back-to-back. adapted from Wolpert 2e, Fig. 4.21 Keller explants show that convergent extension occurs neural ectoderm • Both neural ectoderm and axial mesoderm elongate dramatically • Conclusion: dorsal NIMZ and IMZ both undergo convergent extension. mesoderm adapted from Wolpert 2e, Fig. 4.21 Keller explants allow analysis of convergent extension in an opaque embryo Conclusion: The dorsal IMZ undergoes dramatic convergent extension courtesy Ray Keller Convergent extension involves polarized protrusions protrusions A P mediolateral Cells become polarized, extending protrusions along an axis perpendicular to the axis of extension Wolpert et al 2e, Fig. 8.27 The planar cell polarity pathway is required for convergent extension Control Dsh dominant negative (disrupts PCP) Conclusion: PCP signaling is required for convergent extension Ewald, A. J. et al. Development 2004;131:6195-6209 Convergent extension requires myosin II: normal Actin networks form within cells Skoglund, P. et al.(2008). Development 135:2435-2444 Convergent extension requires myosin II: knockdown Normal protrusion is blocked, and actin networks do not form Skoglund, P. et al.(2008). Development 135:2435-2444 Convergent extension requires myosin II A P Conclusion: Non-muscle myosin II forms complex networks within IMZ cells. It is required for convergent extension Skoglund, P. et al.(2008). Development 135:2435-2444 Gastrulation involves reg...
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This note was uploaded on 11/08/2013 for the course ZOOLOGY 470 taught by Professor Hardin during the Fall '12 term at Wisconsin.

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