11 Flashcards
Noggin and neuralation
Noggin is a BMP antagonist, needed to make sure that ectoderm doesnt turn into epidermis
Noggin mutants fail to undergo neurulation.
Noggin is a secreted antagonist of BMPs. Noggin directly binds to BMPs, preventing them from interacting with their receptors, resulting in reduced activation of the Smad transcription factors.
Turns out that - a certain level of BMP signaling, neither too high or too low, is required for apical constriction during neurulation.
For neuralation to occur what happens to the cells
become columnarized: look like columns becausemicrfotubules elongate but become narrow at the apical side
Failure to close neural tube
malformation (intrinsic things cause this to happen)
Failure to close posterior neural tube
Spina Befida (not lethal)
Failure to close anterior neural tube
Anencephaly (lethal)
Open ends of the neural tube are called
anterior and posterior neuropore
What can prevent spina befinda
Folate vitaminds (vitamin B)
but there is a folate binding protein expressed on dorsalmost area of neural tube at time of fusion (below)
fungal contaminant in food crops may also contribute to neural tube defects by disrupting the folate receptor pathway – fungal contaminant acts as a teratogen (the mycotoxin is called fumonisin)
Recent research has found high levels of fumonisin-type mycotoxins (produced by Fusarium) in organic corn products.
teratogen is something that dsirupts proper development
what does the neural tube establish
dorsal ventral polarity
IN spine cord:
-dorsal region is where spinal neurons receive input from sensory neurons
-ventral region is where motor neurons are found
-in between are interneurons that relay information between the sensory neurons and the motor neurons
Dorsal ventral established
paracirine factors that are around the neural tube
The notochord secretes Sonic hedgehog (Shh)
The dorsal ectoderm secretes TFG-β proteins (here BMPs).
