title: Neurogenin1 defines zebrafish cranial sensory ganglia precursors.
abstract: Cells delaminate from epithelial placodes to form sensory ganglia in the vertebrate head. We describe the formation of cranial neurogenic placodes in the zebrafish, Danio rerio, using bHLH transcription factors as molecular markers. A single neurogenin gene, neurogenin1 (ngn1), is required for the development of all zebrafish cranial ganglia, which contrasts with other described vertebrates. Expression of ngn1 delineates zebrafish ganglionic placodes, including trigeminal, lateral line, and epibranchial placodes. In addition, ngn1 is expressed in a subset of cells within the otic vesicle that will delaminate to form the octaval (statoacoustic) ganglion. The trigeminal placode is the first to differentiate, and forms just lateral and adjacent to the neural crest. Expression of ngn1 is transient and prefigures expression of a related bHLH transcription factor, neuroD. Interfering with ngn1 function using a specific antisense morpholino oligonucleotide blocks differentiation of all cranial ganglia but not associated glial cells. Lateral line sensory neuromasts develop independently of ngn1 function, suggesting that two derivatives of lateral line placodes, ganglia and migrating primordia, are under separate genetic control.
authors.affiliation: Department of Biological Structure, University of Washington, Seattle 98195-7420, USA.
authors.forename: Peter
authors.initials: P
authors.lastname: Andermann
authors.forename: Josette
authors.initials: J
authors.lastname: Ungos
authors.forename: David W
authors.initials: DW
authors.lastname: Raible
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins; D002454:Cell Differentiation / Q000235:genetics*; D002465:Cell Movement / Q000235:genetics; D005724:Ganglia / Q000196:embryology* / Q000502:physiology; D018507:Gene Expression Regulation, Developmental; D018257:Helix-Loop-Helix Motifs / Q000235:genetics; D009419:Nerve Tissue Proteins / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*; D015027:Zebrafish / Q000196:embryology / Q000235:genetics; D029961:Zebrafish Proteins
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C486337:neurog1 protein, zebrafish