Les power point sont sur le site du Master BS, dans l’onglet de l’UE FMBS106 Guidage axonal -...
-
date post
19-Dec-2015 -
Category
Documents
-
view
221 -
download
1
Transcript of Les power point sont sur le site du Master BS, dans l’onglet de l’UE FMBS106 Guidage axonal -...
Les power point sont sur le site du Master BS, dans l’onglet de l’UE FMBS106
www.masterbs.univ-montp2.fr
Guidage axonal - Développement du cerveau - Remodelage neuronal - Mémoire
1) Attraction by the midline
2) Crossing the midline
3) Molecular changes before and after the crossing
4) AC or PC ? (DRL/WNT5)
5) Fasciculation
Book chapter Navigating intermediate targets: the nervous system midline Dickson and Zou in Cold Spring Harbor Perspect Biol 2010(Neuronal guidance - the biology of brain wiring)
Commissural axons at the midline in vertebrates and Drosophila
Morphogens involved in neuronal guidance and their receptors
Netrins, Slits and their receptors.
Receptor for attraction (DCC)
Receptors for repulsion (UNC5 for Netrins; Robo for Slits)
Guidance-cue receptor signaling strategies.
Mutipe guidance cues control the pathfindingof spinal cord commissuralaxons along the dorso-ventral axis
Midline crossing mutants in Drosophila
Fig. 5.39 in Development ofthe nervous system (book)
Molecular cues controlling the pathway choices at the Drosophila midline:COMM regulates ROBO1 trafficking and midline crossing
Molecular cues controlling the pathway choices at the vertebrate midline:the Slit/Robo and Sema3B, 3F/Neuropilin2systems control midline guidance
A Robo code for lateral positioning
Drosophila ventral nerve cord
Rodent spinal cord
DRL/WNT5 in the Drosophila brain:Grillenzoni et al., Development 2007
Mamalian Ryks in the developing nervous system:Fradkin et al., Trends in Neurosciences 2010
Rein et al., 2002 Current Biology
The mushroom bodies (MBs) in theadult Drosophila brain
midline horizontal branch
Srausfeld et al., MRT 2003 10m
A wild-type neuron
vertical branch10m10m
10m
The drl Receptor Tyrosine Kinase
Fradkin et al., TINS 2010
DRL is not expressed in the MBs (FASII)
DRL is not expressed in the MBs (FASII)
DRL in the embryonic brain
drl LOF mutation induces no apparent defects in the embryonic brainbut do induce defects in the embryonic nerve cord
drl is not expressed in the MB neurons but is required for the MB development
Grillenzoni et al., Development 2007
-/-
+/--/-
mutant phenotype ?mutant phenotype
-/-
cell-autonomous ?
MARCM clones
-/-
-/-
mutant phenotype
-/-
+/-
No mutant phenotype, therefore non cell-autonomous
+/+
+/+
Wnt5-/Y; -GAL4 UAS-mGFP/+
Wnt5-/Y; -GAL4 UAS-mGFP/+; UAS-Wnt5/+
Conclusions:Wnt5 is necessary for the axonal growthin an intrinsic manner
axon
WNT5?
Secreted protein
Transmembranereceptor
axonalgrowth
A growing axon
axon
extrinsic MB axon
LIOstop WNT5?
RTK
A stoping axon
Structural features of Ryk subfamily receptors
Cleavage and nuclear translocation of the Ryk intracellular domain (ICD) mediates neurogenesis
Wnt/Ryk-mediated axon repulsion in thedeveloping versus injured adult spinal cord
Ephrins and their Eph receptors
Wnt/Ryk-mediated axon repulsion counterbalances ephrinB1/EphB-mediatedattraction in retinotopic mapping