retinotectal outflow Flashcards
chemical affinity hypothesis
retino-tectal connectivity is based on preset chemical connections established early in development. these are based on target selections made by retinal ganglion cell axons and are due to cell-cell adhesions and cell-ecm interactions
what regulates choice points for axon targeting
epigenetic factors
how does the growth cone affect target selection
it is a sensing organ and responds to signals based on cytoskeletal changes
how does the environment affect pathfinding
adhesion to substrates generates motive force in pathfinding.
what molecules are important substrate binding molecules?
laminins, collagen, fibronectin, CSPG-HSPG
what family are the receptors for the cell surface molecules that act as axon guidance cues
IgG superfamily. all signals can act as attractive or repulsive based on receptor.
what do semaphorins do?
they are generally repulsive and cause growth cone collapse
what is the major semaphorin?
sema3a
what are the receptors for semaphorins
neuropillin and plexin
what are netrins/
they are attractive guidance molecules secreted by the floor plate
is netrin 1 repulsive or attractive
both
what are the two netrin recpetors
DCC and UNC5h
what does DCC mediate?
attraction
what does UNC5H mediate?
repulsion
what is the mechanism for repulsion or attraction
mechanism is via PKA and cytoskeleton remodeling
