title: Hedgehog and retinoic acid signaling cooperate to promote motoneurogenesis in zebrafish.
abstract: The precise requirements of Hedgehog (Hh) pathway activity in vertebrate central nervous system development remain unclear, particularly in organisms with both maternally and zygotically derived signaling. Here we describe the motoneural phenotype of zebrafish that lack maternal and zygotic contributions of the Hh signaling transducer Smoothened (MZsmo mutants) and therefore are completely devoid of ligand-dependent pathway activation. Some functional primary motoneurons (PMNs) persist in the absence of Hh signaling, and we find that their induction requires both basal Gli transcription factor activity and retinoic acid (RA) signaling. We also provide evidence that RA pathway activation can modulate Gli function in a Hh ligand-independent manner. These findings support a model in which Hh and RA signaling cooperate to promote PMN cell fates in zebrafish.
authors: Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA. johnkennethmich@gmail.com
authors: John K
authors: JK
authors: Mich
authors: James K
authors: JK
authors: Chen
mesh_terms: D000818:Animals; D017931:DNA Primers / Q000235:genetics; D053823:Hedgehog Proteins / Q000378:metabolism*; D017403:In Situ Hybridization; D009046:Motor Neurons / Q000502:physiology*; D055495:Neurogenesis / Q000235:genetics / Q000502:physiology*; D009841:Oligonucleotides / Q000235:genetics; D015513:Oncogene Proteins / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D043562:Receptors, G-Protein-Coupled / Q000172:deficiency*; D015398:Signal Transduction / Q000502:physiology*; D000072086:Smoothened Receptor; D015534:Trans-Activators / Q000378:metabolism; D014212:Tretinoin / Q000378:metabolism*; D015027:Zebrafish / Q000502:physiology*; D029961:Zebrafish Proteins / Q000172:deficiency*; D000071676:Zinc Finger Protein GLI1
chemical_list: D017931:DNA Primers; D053823:Hedgehog Proteins; D009841:Oligonucleotides; D015513:Oncogene Proteins; D043562:Receptors, G-Protein-Coupled; D000072086:Smoothened Receptor; D015534:Trans-Activators; D029961:Zebrafish Proteins; D000071676:Zinc Finger Protein GLI1; C491021:smo protein, zebrafish; D014212:Tretinoin