title: carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (cad) regulates Notch signaling and vascular development in zebrafish.
abstract: BACKGROUND
  The interplay between Notch and Vegf signaling regulates angiogenesis in the embryo. Notch signaling limits the responsiveness of endothelial cells to Vegf to control sprouting. Despite the importance of this regulatory relationship, much remains to be understood about extrinsic factors that modulate the pathway.
  
  
  RESULTS
  During a forward genetic screen for novel regulators of lymphangiogenesis, we isolated a mutant with reduced lymphatic vessel development. This mutant also exhibited hyperbranching arteries, reminiscent of Notch pathway mutants. Positional cloning identified a missense mutation in the carbamoyl-phosphate synthetase 2, aspartate transcarbamylase, and dihydroorotase (cad) gene. Cad is essential for UDP biosynthesis, which is necessary for protein glycosylation and de novo biosynthesis of pyrimidine-based nucleotides. Using a transgenic reporter of Notch activity, we demonstrate that Notch signaling is significantly reduced in cad(hu10125) mutants. In this context, genetic epistasis showed that increased endothelial cell responsiveness to Vegfc/Vegfr3 signaling drives excessive artery branching.
  
  
  CONCLUSIONS
  These findings suggest important posttranslational modifications requiring Cad as an unappreciated mechanism that regulates Notch/Vegf signaling during angiogenesis.
authors.affiliation: Division of Molecular Genetics and Development, Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD, Australia.
authors.forename: Baptiste
authors.initials: B
authors.lastname: Coxam
authors.forename: Christine
authors.initials: C
authors.lastname: Neyt
authors.forename: Daniela R
authors.initials: DR
authors.lastname: Grassini
authors.forename: Ludovic
authors.initials: L
authors.lastname: Le Guen
authors.forename: Kelly A
authors.initials: KA
authors.lastname: Smith
authors.forename: Stefan
authors.initials: S
authors.lastname: Schulte-Merker
authors.forename: Benjamin M
authors.initials: BM
authors.lastname: Hogan
mesh_terms: D000818:Animals; D001221:Aspartate Carbamoyltransferase / Q000235:genetics / Q000378:metabolism*; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing) / Q000235:genetics / Q000378:metabolism*; D004080:Dihydroorotase / Q000235:genetics / Q000378:metabolism*; D006031:Glycosylation; D018919:Neovascularization, Physiologic / Q000502:physiology*; D051880:Receptors, Notch / Q000235:genetics / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D042582:Vascular Endothelial Growth Factor C / Q000235:genetics / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000235:genetics / Q000378:metabolism; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: C033626:CAD trifunctional enzyme; D051880:Receptors, Notch; D042582:Vascular Endothelial Growth Factor C; D029961:Zebrafish Proteins; C493178:vascular endothelial growth factor C, zebrafish; D001221:Aspartate Carbamoyltransferase; D040321:Vascular Endothelial Growth Factor Receptor-3; D004080:Dihydroorotase; D002223:Carbamoyl-Phosphate Synthase (Glutamine-Hydrolyzing)
keywords: Notch; Vegfc; angiogenesis; glycosylation; lymphangiogenesis; zebrafish