L12 GOK Flashcards
Describe robo expression on axon before /after crossing midline of sc ?
low expression before crossing
regulated expression after crossing
Robo receptors upregulated and trafficked to cell surface under control of ?
comissureless
why dont robo1 not respond to slit before crossing
Robo3 silences repulsive slit signalling mediated by robo1 and 2 allowing axons to cross
what is robo 3?
KO affect ?
decoy receptor for slit - it binds and nothing happens
allows crossing of axons at midline
ko- axons fail to cross midline
what happens to expression of robo3 , robo2 and 1 when the axons cross midline ?
down regulated robo3 expression and upregulated robo1 and 2
what are the two requirements for axon expulsion from the midline ?
upregulation of axons responsiveness to midline repellents (Robo receptors).
2) attractive response of axons to netrins switched off (silenced) as axons cross.
how is netrin silenced once axons have crossed the midline ?
activation of Robo by Slits.
- activation of Robo causes its cytoplasmic domain to bind cytoplasmic domain of DCC, which prevent DCC from transducing an attractive response to netrin.
after midline crossing what signal makes axons turn anteriorly ?
longitudinal guidance by wnt transduced by Frizzled3 receptor
corticospinal neurons are repelled by what molecule and move posteriorly in sc ?
wnt
gradient of wnt in sc related to comissural neurons ?
attractive anterior posterior gradient
Horizontal Gaze Palsy and Progressive Scoliosis carry mutants for what gene ?
robo 3
