title: Temporal and spatial requirements for Nodal-induced anterior mesendoderm and mesoderm in anterior neurulation.
abstract: Zebrafish with defective Nodal signaling have a phenotype analogous to the fatal human birth defect anencephaly, which is caused by an open anterior neural tube. Previous work in our laboratory found that anterior open neural tube phenotypes in Nodal signaling mutants were caused by lack of mesendodermal/mesodermal tissues. Defects in these mutants are already apparent at neural plate stage, before the neuroepithelium starts to fold into a tube. Consistent with this, we found that the requirement for Nodal signaling maps to mid-late blastula stages. This timing correlates with the timing of prechordal plate mesendoderm and anterior mesoderm induction, suggesting these tissues act to promote neurulation. To further identify tissues important for neurulation, we took advantage of the variable phenotypes in Nodal signaling-deficient sqt mutant and Lefty1-overexpressing embryos. Statistical analysis indicated a strong, positive correlation between a closed neural tube and presence of several mesendoderm/mesoderm-derived tissues (hatching glands, cephalic paraxial mesoderm, notochord, and head muscles). However, the neural tube was closed in a subset of embryos that lacked any one of these tissues. This suggests that several types of Nodal-induced mesendodermal/mesodermal precursors are competent to promote neurulation.
authors.affiliation: Department of Biology, University of Minnesota Duluth, Duluth, MN.|Integrated Biosciences Graduate Program, University of Minnesota, Duluth, MN.
authors.forename: Ngawang
authors.initials: N
authors.lastname: Gonsar
authors.affiliation: Department of Biology, University of Minnesota Duluth, Duluth, MN.|Integrated Biosciences Graduate Program, University of Minnesota, Duluth, MN.
authors.forename: Alicia
authors.initials: A
authors.lastname: Coughlin
authors.affiliation: Department of Biology, University of Minnesota Duluth, Duluth, MN.
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Clay-Wright
authors.affiliation: Department of Biology, University of Minnesota Duluth, Duluth, MN.
authors.forename: Bethanie R
authors.initials: BR
authors.lastname: Borg
authors.affiliation: Department of Biology, University of Minnesota Duluth, Duluth, MN.|Integrated Biosciences Graduate Program, University of Minnesota, Duluth, MN.
authors.forename: Lexy M
authors.initials: LM
authors.lastname: Kindt
authors.affiliation: Department of Biology, University of Minnesota Duluth, Duluth, MN.|Integrated Biosciences Graduate Program, University of Minnesota, Duluth, MN.
authors.forename: Jennifer O
authors.initials: JO
authors.lastname: Liang
mesh_terms: D000757:Anencephaly; D000818:Animals; D056726:Genetic Association Studies; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics / Q000378:metabolism; D008648:Mesoderm / Q000378:metabolism*; D054259:Neural Tube / Q000378:metabolism*; D054261:Neurulation / Q000235:genetics; D055457:Nodal Protein / Q000235:genetics / Q000378:metabolism*; D009672:Notochord / Q000378:metabolism*; D015398:Signal Transduction; D062211:Spatio-Temporal Analysis; D015027:Zebrafish / Q000196:embryology*; D029961:Zebrafish Proteins
chemical_list: D018398:Homeodomain Proteins; D047908:Intracellular Signaling Peptides and Proteins; D055457:Nodal Protein; D029961:Zebrafish Proteins
keywords: Nodal; anencephaly; neural tube defects; zebrafish