Development of branchiomotor neurons in zebrafish.
The mechanisms underlying neuronal specification and axonogenesis in the vertebrate hindbrain are poorly understood. To address these questions, we have employed anatomical methods and mutational analysis to characterize the branchiomotor neurons in the zebrafish embryo. The zebrafish branchiomotor system is similar to those in the chick and mouse, except for the location of the nVII and nIX branchiomotor neurons. Developmental analyses of genes expressed by branchiomotor neurons suggest that the different location of the nVII neurons in the zebrafish may result from cell migration. To gain insight into the mechanisms underlying the organization and axonogenesis of these neurons, we examined the development of the branchiomotor pathways in neuronal mutants. The valentino b337 mutation blocks the formation of rhombomeres 5 and 6, and severely affects the development of the nVII and nIX motor nuclei. The cyclops b16 mutation deletes ventral midline cells in the neural tube, and leads to a severe disruption of most branchiomotor nuclei and axon pathways. These results demonstrate that rhombomere-specific cues and ventral midline cells play important roles in the development of the branchiomotor pathways.
Chandrasekhar
A
A
Department of Biology, University of Michigan, Ann Arbor 48109-1048, USA.
Moens
C B
CB
Warren
J T
JT
Kimmel
C B
CB
Kuwada
J Y
JY
D000818:Animals; D030161:Avian Proteins; D019521:Body Patterning; D001934:Branchial Region / Q000196:embryology* / Q000294:innervation*; D015816:Cell Adhesion Molecules, Neuronal / Q000096:biosynthesis / Q000235:genetics; D002465:Cell Movement; D058969:Contactin 2; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics; D004627:Embryonic Induction; D015870:Gene Expression; D018398:Homeodomain Proteins / Q000096:biosynthesis / Q000235:genetics; D050977:Maf Transcription Factors; D051258:MafB Transcription Factor; D009046:Motor Neurons; D009154:Mutation; D009419:Nerve Tissue Proteins / Q000096:biosynthesis / Q000235:genetics; D009434:Neural Pathways / Q000196:embryology*; D009436:Neural Tube Defects / Q000235:genetics; D015513:Oncogene Proteins; D012249:Rhombencephalon / Q000166:cytology / Q000196:embryology*; D014157:Transcription Factors / Q000096:biosynthesis / Q000235:genetics; D015027:Zebrafish / Q000196:embryology; D029961:Zebrafish Proteins
D030161:Avian Proteins; C548674:CNTN2 protein, human; D015816:Cell Adhesion Molecules, Neuronal; C548675:Cntn2 protein, mouse; D058969:Contactin 2; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; C490407:MAFB protein, human; D050977:Maf Transcription Factors; D051258:MafB Transcription Factor; C490406:Mafb protein, mouse; D009419:Nerve Tissue Proteins; D015513:Oncogene Proteins; D014157:Transcription Factors; D029961:Zebrafish Proteins; C091157:maf-B protein, chicken; C490408:mafbb protein, zebrafish