20. Cell interactions In neural development Flashcards
briefly describe the process of neurulation
dorsal most-ectoderm thickens and evaginates
neural folds fuse creating neural tube
notochord under the tube made of underlying mesoderm
what is the purpose of lateral inhibition
once one cell adopts a fate - it sends signals to prevent other cells from doing the same
what is the purpose of Notch in drosophila
inhibits the neural fate in the neurectoderm
describe the different notch mutants in drosophila
- normal notch
- too much notch
- not enough notch
- normal notch = wild-type
- too much notch = missing bristles
- not enough notch = extra bristles
what is SOP
sensory organ precursor
what happens once a SOP is specified
what does this require?
adjacent imaginal disc cells and laterally inhibited from doing the same
requires notch
describe the process of notch signalling
notch binds its receptor via epidermal growth factor repeats
notch conformational change = cleaves the intracellular domain
translocates to the nucleus and binds to CSL family proteins
= target gene transcription
what binds to the notch receptor
DSL proteins
what do DSL stand for
delta/ serrate/ lag2
describe DSL proteins
large membrane proteins
many EGF repeats
involved in lateral inhibitoon
what is a proneural cluster
a cluster of cells that all have the potential to form a SOP = only one SOP per cluster
what 3 proteins do all pro neural cluster cells express
acheate-scute proteins
delta
notch
describe the positive feedback loop of acheate scute
acheate-scute over expression = expression of delta
notch binds on neighbour = activates split proteins that repress acheate-scute expression on neighbouring cells
ALLOWS ONE CELL TO OVEREXPRESS ACHEATE-SCUTE = commits it to SOP future
where are pro neural clusters found
in the imaginal disc
what happens once committed as an SOP
asymmetrical divisions = forms a shaft, socket, neuron or sheath