BIO380H5 Lecture Notes - Lecture 19: Paraxial Mesoderm, Somitogenesis, Fgf8
Document Summary
Somitomeres are primed somites, but they aren"t somites yet. Fgf8 is driving the proliferation, its secreted from the paraxial mesoderm. Slide 17: you are getting an antagonizing relationship between ra and fgf8, the cells here can give rise to either neural tube or mesodermal. Slide 18: as growth occurs, fgf8 and ra boundaries are moving with the wave, the moving boundary is getting new somites to form, you are getting a wave of somitogenesis. If you speed up that clock, you are forming more somites. Speed up notch clock: the reason somitogenesis stops is the notch clock will eventually catch up to the wavefront clock. If ra gets close enough to fgf8, it is able to shut it off, it will shut down somitogenesis. Slide 19: you need to find a mechanism to push the tissue outwards, there is an expanding rod, the scaffolding is coming from the notochord, the expansion allows the cells to build around something.
