title: Motor neurons and oligodendrocytes arise from distinct cell lineages by progenitor recruitment.
abstract: During spinal cord development, ventral neural progenitor cells that express the transcription factors Olig1 and Olig2, called pMN progenitors, produce motor neurons and then oligodendrocytes. Whether motor neurons and oligodendrocytes arise from common or distinct progenitors in vivo is not known. Using zebrafish, we found that motor neurons and oligodendrocytes are produced sequentially by distinct progenitors that have distinct origins. When olig2(+) cells were tracked during the peak period of motor neuron formation, most differentiated as motor neurons without further cell division. Using time-lapse imaging, we found that, as motor neurons differentiated, more dorsally positioned neuroepithelial progenitors descended to the pMN domain and initiated olig2 expression. Inhibition of Hedgehog signaling during motor neuron differentiation blocked the ventral movement of progenitors, the progressive initiation of olig2 expression, and oligodendrocyte formation. We therefore propose that the motor neuron-to-oligodendrocyte switch results from Hedgehog-mediated recruitment of glial-fated progenitors to the pMN domain subsequent to neurogenesis.
authors.affiliation: Department of Pediatrics, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Ravanelli
authors.affiliation: Department of Pediatrics, Department of Cell and Developmental Biology, University of Colorado School of Medicine, Aurora, Colorado 80045, USA.
authors.forename: Bruce
authors.initials: B
authors.lastname: Appel
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism; D002454:Cell Differentiation; D019070:Cell Lineage; D002465:Cell Movement; D004625:Embryo, Nonmammalian; D018507:Gene Expression Regulation, Developmental; D053823:Hedgehog Proteins / Q000378:metabolism; D009046:Motor Neurons / Q000166:cytology*; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D046569:Neuroepithelial Cells / Q000166:cytology; D055495:Neurogenesis / Q000502:physiology; D000076104:Oligodendrocyte Transcription Factor 2; D009836:Oligodendroglia / Q000166:cytology*; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D013234:Stem Cells / Q000166:cytology*; D015027:Zebrafish / Q000196:embryology* / Q000235:genetics; D029961:Zebrafish Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D053823:Hedgehog Proteins; D009419:Nerve Tissue Proteins; D000076104:Oligodendrocyte Transcription Factor 2; D029961:Zebrafish Proteins; C465361:olig2 protein, zebrafish
keywords: Sonic hedgehog; motor neurons; neural progenitors; oligodendrocytes; pMN domain; zebrafish