Dynamic temporal and cell type-specific expression of Wnt signaling components in the developing midbrain.
Wnt1 and -5a have been shown to modulate the proliferation and differentiation of midbrain dopaminergic (DA) neurons. However, it is not known whether other Wnts or which Frizzled (Fz) receptors are expressed in the developing midbrain. We found that 13 out of 19 Wnts, all 10 Fzs, and several intracellular Wnt signaling modulators, including Axin, FRAT, Naked, Par-1, and Ltap are developmentally regulated between embryonic days (E) 10.5 and 15.5. Next, we studied whether Fzs are differentially expressed in different cell types and examined neuronal-progenitor- or glial-enriched cultures and DA neurons isolated from TH-GFP reporter mice. We found that Fz8 is expressed at high levels in DA neurons at E11.5 and E13.5. Fz6 and -7 are the predominant transcripts in glial precursors, and Fz9, which is absent in DA neurons at E11.5, is the main receptor expressed in neuronal precursors. We therefore examined the function of Fz9 in DA cells and found that overexpression of Fz9 reduced Wnt5a- but not Wnt3a-induced hyperphosphorylation of Dishevelled. Thus, our results show that Fzs are developmentally regulated and differentially expressed in VM precursors, DA neurons, and glia. These findings suggest that Fz expression contributes to provide specificity to Wnt-mediated effects.
Rawal
Nina
N
Laboratory of Molecular Neurobiology, Medical Biochemistry and Biophysics, Karolinska Institute, Scheeles väg 1, A1:2, 171 77 Stockholm, Sweden.
Castelo-Branco
Gonçalo
G
Sousa
Kyle M
KM
Kele
Julianna
J
Kobayashi
Kazuto
K
Okano
Hideyuki
H
Arenas
Ernest
E
D048868:Adaptor Proteins, Signal Transducing / Q000378:metabolism; D000818:Animals; D060466:Axin Protein; D002460:Cell Line; D002478:Cells, Cultured; D000072261:Dishevelled Proteins; D005260:Female; D051157:Frizzled Receptors / Q000235:genetics; D018507:Gene Expression Regulation, Developmental; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics; D008297:Male; D008636:Mesencephalon / Q000166:cytology / Q000196:embryology / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D009419:Nerve Tissue Proteins / Q000235:genetics; D010750:Phosphoproteins / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000494:pharmacology; D051381:Rats; D017981:Receptors, Neurotransmitter / Q000235:genetics; D011994:Recombinant Proteins / Q000494:pharmacology; D012097:Repressor Proteins / Q000235:genetics; D015398:Signal Transduction / Q000235:genetics*; D014162:Transfection; D051153:Wnt Proteins / Q000235:genetics* / Q000494:pharmacology; D000071818:Wnt-5a Protein
D048868:Adaptor Proteins, Signal Transducing; D060466:Axin Protein; D000072261:Dishevelled Proteins; D051157:Frizzled Receptors; C403212:Fzd9 protein, mouse; D047908:Intracellular Signaling Peptides and Proteins; D009419:Nerve Tissue Proteins; D010750:Phosphoproteins; D011518:Proto-Oncogene Proteins; D017981:Receptors, Neurotransmitter; D011994:Recombinant Proteins; D012097:Repressor Proteins; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; C438615:Wnt5a protein, mouse; D017346:Protein Serine-Threonine Kinases