CSB328H1 Chapter Notes - Chapter 8: Archenteron, Intermediate Mesoderm, Hindbrain
22 Oct 2013
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Noggin, chordin, and follistatin are all secreted by the organizer, and that each of them prevents bmp from binding to and inducing the ectoderm and mesoderm cells near the organizer. Bmp4 is expressed initially throughout the ectodermal and mesodermal regions of the late blastula. During gastrulation, bmp4 transcripts become restricted to the ventrolateral marginal zone because the goosecoid protein is induced by the. Siamois/twin and smad2 interactions in the dorsal mesoderm starting at the beginning of gastrulation. These tfs repress bmp4 and wnt8 transcription. In the ectoderm, bmps repress the genes involved in forming neural tissue while activating other genes involved in epidermal specification. In the mesoderm, it appears that graded levels of bmp4 activate different sets of mesodermal genes: an absence of bmp4 specifies the dorsal mesoderm, low amount specifies the intermediate mesoderm, high amount specifies the lateral mesoderm. Inactivation of 3 bmps & admp (another bmp family protein) -> entire ectoderm became neural.
