MCD BIO 138 Lecture Notes - Lecture 10: Cortical Reaction, Activin And Inhibin, Animal
15 Dec 2016
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Document Summary
Ectoderm and endoderm are specified in the early blastula (maternal) Mesoderm forms from cells at border between endoderm and ectoderm in late blastula (zygotic) Mesoderm is induced in animal cap cells by signals from vegetal cells/endoderm. Failure to form endoderm -> failure to induce mesoderm. Diff types of mesoderm form from dorsal/ventral regions of equatorial zone in late blastula embryo. Cortical rotation -> cytoskeleton rearrangement -> localization of maternal determinants on dorsal side. Inhibit bmp4 binding -> bmp gradient along d/v --> formation of diff mesoderm. Produces secreted factors that influence surrounding cells and lead to their determination to follow specific developmental pathways. If transplanted, the recipient will have a duplicated axis. Does not itself give rise to new dorsal tissue. Forms where there is a lot of b-catenin in dorsal vegetal cells + when exposed to. Region of high b-cat activity established by cortical reaction. B cat and vegtt activate nodal-related protein transcription.
