Visualization of cranial motor neurons in live transgenic zebrafish expressing green fluorescent protein under the control of the islet-1 promoter/enhancer.
We generated germ line-transmitting transgenic zebrafish that express green fluorescent protein (GFP) in the cranial motor neurons. This was accomplished by fusing GFP sequences to Islet-1 promoter/enhancer sequences that were sufficient for neural-specific expression. The expression of GFP by the motor neurons in the transgenic fish enabled visualization of the cell bodies, main axons, and the peripheral branches within the muscles. GFP-labeled motor neurons could be followed at high resolution for at least up to day four, when most larval neural circuits become functional, and larvae begin to swim and capture prey. Using this line, we analyzed axonal outgrowth by the cranial motor neurons. Furthermore, by selective application of DiI to specific GFP-positive nerve branches, we showed that the two clusters of trigeminal motor neurons in rhombomeres 2 and 3 innervate different peripheral targets. This finding suggests that the trigeminal motor neurons in the two clusters adopt distinct fates. In future experiments, this transgenic line of zebrafish will allow for a genetic analysis of cranial motor neuron development.
Higashijima
S
S
Inheritance and Variation Group, Precursory Research for Embryonic Science and Technology, Japan Science and Technology Corporation, Honmachi, Kawaguchi, Saitama 332-0012, Japan. shigashijima@notes.cc.sunysb.edu
Hotta
Y
Y
Okamoto
H
H
D000818:Animals; D002232:Carbocyanines; D004742:Enhancer Elements, Genetic / Q000502:physiology; D005154:Facial Nerve / Q000166:cytology / Q000254:growth & development; D005456:Fluorescent Dyes; D018507:Gene Expression Regulation, Developmental; D017930:Genes, Reporter; D005930:Glossopharyngeal Nerve / Q000166:cytology / Q000254:growth & development; D049452:Green Fluorescent Proteins; D018398:Homeodomain Proteins / Q000235:genetics*; D007202:Indicators and Reagents / Q000378:metabolism*; D060850:LIM-Homeodomain Proteins; D007814:Larva / Q000166:cytology / Q000502:physiology; D008164:Luminescent Proteins / Q000235:genetics*; D009046:Motor Neurons / Q000502:physiology*; D018482:Muscle, Skeletal / Q000294:innervation; D016296:Mutagenesis / Q000502:physiology; D009419:Nerve Tissue Proteins; D009475:Neurons, Afferent / Q000166:cytology / Q000502:physiology; D009802:Oculomotor Nerve / Q000166:cytology / Q000254:growth & development; D030781:Organisms, Genetically Modified; D011401:Promoter Regions, Genetic / Q000502:physiology*; D014157:Transcription Factors; D014276:Trigeminal Nerve / Q000166:cytology* / Q000254:growth & development; D014630:Vagus Nerve / Q000166:cytology / Q000254:growth & development; D015027:Zebrafish
C101089:CM-DiI; D002232:Carbocyanines; D005456:Fluorescent Dyes; D018398:Homeodomain Proteins; D007202:Indicators and Reagents; D060850:LIM-Homeodomain Proteins; D008164:Luminescent Proteins; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; C063843:insulin gene enhancer binding protein Isl-1; D049452:Green Fluorescent Proteins