4-1-13_frogs_pt_3

Et al2008 development 1352435 2444 gastrulation

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Unformatted text preview: ion-specific behaviors Adapted from Gilbert 9e, Fig. 7.10 Gastrulation involves region-specific behaviors Leading edge mesoderm: directed migration blastocoel roof migrating cells Leading edge cells migrate along the blastocoel roof, where oriented fibronectin fibrils are found. courtesy Ray Keller Leading edge mesoderm undergoes directed migration Leading edge mesoderm cells undergo directed migration at the front edge of the involuting material see Gilbert, 9e, Fig. 7.10 Leading edge mesoderm cells migrate via lamellipodia anterior lamellipodia posterior courtesy Ray Keller The axolotl, Ambystoma mexicanum is useful for studying leading edge mesoderm Axolotls are interesting because the exhibit neoteny, i.e., they become reproductively mature while maintaining juvenile (larval) characteristics. In addition, they are useful for studying leading edge migration during gastrulation. The blastocoel roof has oriented fibronectin fibrils Gilbert, 4e, Fig. 4.25 Fibronectin fibrils have an overall orientation along the anteriorposterior axis (i.e. the direction leading edge cells normally migrate) Antibodies can be used to disrupt fibronectin fibrils Antibodies injected into the blastocoel disrupt binding of cells to fibronectin. Kalthoff, 2e, Fig. 11.24 Involution normally occurs in axolotl embryos Involution normally pushes the blastocoel (bc) out of the way, forming the archenteron (ar), and covering the yolk plug (yp) Gilbert, 4e, Fig. 4.26 Disrupting attachment to fibronectin blocks mesoderm migration ectoderm (wrinkled) blastocoel not displaced mesoderm (failed to involute) endoderm not covered Involution is blocked in embryos injected with anti-FN antibodies Conclusion: FN is needed for mesoderm migration Gilbert, 4e, Fig. 4.26...
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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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