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Ectoderm Fate. Neural tube development Building the brain You can see a lot by looking! The eye Epidermis development. Brief overview on Ectoderm fate. Neural Tube Development. Primary and Secondary Neurulation .
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Ectoderm Fate • Neural tube development • Building the brain • You can see a lot by looking! The eye • Epidermis development
Neural Tube Development • Primary and Secondary Neurulation. • Primary Neurulation is Anterior portion of NT development, whereas posterior is secondary neurulation
Neural Tube closure • Either single or multiple points of closure • A-P neuropores • Problems with closure • Spina bifida • Anencephaly • craniorachischisis
Control of neural tube closure • Genetic factors: • Pax3, Sonic hedgehog, and openbrain • Environmental factors: • Cholesterol and Folate
Secondary Neurulation • Formation of Medullary cord
Eye Field formation • Otx gene expression is high • BMP, wnt signaling low • Pax6 master regulator
Too much of a good thing? • Increase in Sonic hedgehog • Widespread decrease in Pax6
Retina differentiation • Most Ventral cells=Pax2; optic stalk • Dorsal cells= BMPs, Rx1 • Rx1 regulates Pax6 and Six3
Retina differentiation • Fate of neuroblast determined by translation, not transcription • Photoacceptor genes regulated by Xotx5b • Xotx2 and Xvsx1 specify bipolar neurons. • All transcribed in retinal cells • Translation regulated by miRNAs • miR129 • miR155 • miR214 • miR222