Guigage axonal dans le système nerveux ventral chez Drosophila: rôles du récepteur DRL et de son ligand WNT5 Jean-Maurice Dura Institut de Génétique Humai [email protected]Callahan et al., Nature 1995 Bonkowsky et al., Nature 1999 Yoshikawa et al., Nature 2003
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Guigage axonal dans le système nerveux ventral chez Drosophila: rôles du récepteur DRL et de son ligand WNT5 Jean-Maurice Dura Institut de Génétique Humaine.
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Guigage axonal dans le système nerveux ventral chezDrosophila: rôles du récepteur DRL et de son ligand WNT5
Callahan et al., Nature 1995Bonkowsky et al., Nature 1999Yoshikawa et al., Nature 2003
Strong similarities between Drosophila and human
• More than 50% of the 15.000 Drosophila genes have a strong similarity with a human gene.
• Amongst 289 human genes involved in a severe pathology, 177 have a clear homologue in Drosophila. • Numerous molecular pathway are very well conserved (signal transduction; neurotransmitters; etc......).
Crible “enhancer trap” avec P[etau-lacZ] qui permetde bien visualiser les trajets axonaux - crible de 2400nouvelles insertions au hasard.
in yeastGAL4 881 aa: regulator of transcription of genes induced by galactose (GAL10 and GAL1) by directly binding to 4 related 17 bp sites defining an Upstream Activating Sequences (UAS)
in Drosophila (transgenesis via P transposable element)
(no deleterious effect)
eagle-GAL4 + UAS-tau-lacZ +UAS-drl +UAS-drlE:cross in AC + PC cross only in AC cross in AC + PC
drl instructs crossing axons to choose AC: - attractive to AC?
+ UAS-comm : crossing in AC +PC+ UAS-comm + UAS-drl : crossing only in AC+ UAS-comm + UAS-drlE : crossing in AC +PC
The DRL protein
DRL-myc soluble extracellular domain probe:should correspond to putative DRL ligand
red: DRL-mycgreen: endogenousdrl expression
Looking for the ligand
genetic screen for DRL ligand:suppression of drl gain-of-function80% genome deficiencies screeneg-GAL4 UAS-drl; def/+250 defs one by oneOne particular def is selected, then overlaping defs,and finally producing mutant of interesting gene
Wnt5 transcripts are localized in the PC
WNT5 protein is localized in the PC and in the AC
DRL-myc soluble extracellular domain probe:should correspond to putative DRL ligand
red: DRL-mycgreen: endogenousdrl expression
myc
Embryos stained with BP102 (all axons)
embryos stained for subsets of AC axons:+/Y; drlP/+ +/Y; drlP/drlR Wnt5D7/Y; drlP/+
embryos stained forsubsets of PC axons:Wnt5 mutants are normal
embryos stained for all axons: anti-HRPmidline glia GAL4/UAS-Wnt5;
drl+/drl+ drl-/drl-
Fc
embryos stained with DRL-Fc
DRL-Fc
embryos stained with DRL-Fc
drl- embryos stained with DRL-Fc DRL-Fc immunoprecipitates WNT5