Presynaptic development at the Drosophila neuromuscular junction: assembly and localization of presynaptic active zones.
We describe the extent to which presynaptic structures at the embryonic neuromuscular junction of Drosophila can form in mutants where development of postsynaptic somatic muscles is affected. Although twist mutant embryos lack mesoderm, motor axons still grow out of the CNS and form morphologically normal presynaptic active zones, independent of their target cells. In myoblast city mutant embryos, myoblasts do not fuse but form fully differentiated mononucleate muscles, which make functional neuromuscular synapses with correctly localized presynaptic active zones. Myoblasts also fail to fuse but still attract appropriate innervation in mef2 mutant embryos. However, these myoblasts fail to differentiate into muscles and presynaptic active zones fail to localize at neuromuscular contacts. Thus, the process of synapse formation can be genetically separated from the process of target recognition, revealing that localization of presynaptic active zones requires mef2-dependent muscle differentiation.
Department of Zoology, University of Cambridge, United Kingdom.
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Prokop
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Landgraf
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Rushton
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Broadie
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Bate
D000818:Animals; D001369:Axons / Q000502:physiology* / Q000648:ultrastructure; D002454:Cell Differentiation; D004268:DNA-Binding Proteins / Q000235:genetics / Q000502:physiology; D004330:Drosophila / Q000196:embryology* / Q000235:genetics; D029721:Drosophila Proteins; D004625:Embryo, Nonmammalian; D017344:Genes, Insect; D064326:MEF2 Transcription Factors; D008564:Membrane Potentials; D008648:Mesoderm; D009046:Motor Neurons / Q000502:physiology / Q000648:ultrastructure; D009132:Muscles / Q000166:cytology / Q000196:embryology / Q000294:innervation; D018006:Myogenic Regulatory Factors; D009412:Nerve Fibers / Q000502:physiology / Q000648:ultrastructure; D009469:Neuromuscular Junction / Q000502:physiology* / Q000648:ultrastructure; D017354:Point Mutation; D017384:Sequence Deletion; D013569:Synapses / Q000502:physiology* / Q000648:ultrastructure; D014157:Transcription Factors / Q000235:genetics / Q000502:physiology
D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D064326:MEF2 Transcription Factors; C499409:Mef2 protein, Drosophila; D018006:Myogenic Regulatory Factors; D014157:Transcription Factors