The Drosophila beaten path gene encodes a novel secreted protein that regulates defasciculation at motor axon choice points.
In the Drosophila embryo, at specific choice points along the major motor nerves, subsets of motor axons defasciculate and then steer into their muscle target regions. Here we describe the analysis of beaten path (beat), a gene required for the selective defasciculation of motor axons at these choice points. In beat mutant embryos, motor axons fail to defasciculate and bypass their targets. This phenotype is suppressed by mutations in FasII and conn, two genes encoding cell adhesion molecules expressed on motor axons, suggesting that beat provides an antiadhesive function. beat encodes a novel secreted protein that is expressed by motoneurons during outgrowth. Rescue and ectopic expression experiments support the model that Beat protein is secreted by motor axons where it functions to regulate their selective defasciculation at specific choice points.
Fambrough
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Howard Hughes Medical Institute, Department of Molecular and Cell Biology, University of California, Berkeley 94720, USA.
Goodman
C S
CS
D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000737:chemistry / Q000378:metabolism / Q000502:physiology*; D002448:Cell Adhesion / Q000502:physiology; D015816:Cell Adhesion Molecules, Neuronal / Q000235:genetics / Q000378:metabolism; D002874:Chromosome Mapping; D003001:Cloning, Molecular; D064211:Connectin; D004330:Drosophila / Q000235:genetics*; D029721:Drosophila Proteins; D018507:Gene Expression Regulation, Developmental / Q000502:physiology; D017344:Genes, Insect / Q000502:physiology; D008565:Membrane Proteins / Q000235:genetics; D008969:Molecular Sequence Data; D009046:Motor Neurons / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D009124:Muscle Proteins / Q000235:genetics / Q000378:metabolism; D009132:Muscles / Q000737:chemistry / Q000294:innervation / Q000502:physiology; D016296:Mutagenesis / Q000502:physiology; D009419:Nerve Tissue Proteins / Q000235:genetics* / Q000378:metabolism; D016501:Neurites / Q000737:chemistry / Q000378:metabolism / Q000502:physiology; D010641:Phenotype; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism
D015816:Cell Adhesion Molecules, Neuronal; D064211:Connectin; D029721:Drosophila Proteins; D008565:Membrane Proteins; D009124:Muscle Proteins; D009419:Nerve Tissue Proteins; D012333:RNA, Messenger; C103224:beat-Ia protein, Drosophila; C051642:fasciclin II; D011494:Protein Kinases