Homeotic genes influence the axonal pathway of a Drosophila embryonic sensory neuron.
Each abdominal hemisegment of the Drosophila embryo has two sensory neurons intimately associated with a tracheal branch. During embryogenesis, the axons of these sensory neurons, termed the v'td2 neurons, enter the CNS and grow toward the brain with a distinctive pathway change in the third thoracic neuromere. We show that the axons use guidance cues that are under control of the bithorax gene complex (BX-C). Pathway defects in mutants suggest that a drop in Ultrabithorax expression permits the pathway change in the T3 neuromere, while combined Ultrabithorax and abdominal-A expression represses it in the abdominal neuromeres. We propose that the axons do not respond to a particular segmental identity in forming the pathway change; rather they respond to pathfinding cues that come about as a result of a drop in BX-C expression along the antero-posterior axis of the CNS.
Merritt
David J
DJ
School of Life Sciences, The University of Queensland, Brisbane, Australia. dmerritt@zen.uq.edu.au
Whitington
Paul M
PM
D000483:Alleles; D000818:Animals; D001369:Axons / Q000378:metabolism / Q000502:physiology*; D002490:Central Nervous System / Q000648:ultrastructure; D004268:DNA-Binding Proteins / Q000502:physiology*; D004330:Drosophila / Q000196:embryology*; D029721:Drosophila Proteins / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental; D018398:Homeodomain Proteins / Q000502:physiology*; D008954:Models, Biological; D009154:Mutation; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D017933:Peripheral Nervous System / Q000378:metabolism; D014157:Transcription Factors
C410542:Abd-A protein, insect; D004268:DNA-Binding Proteins; D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D014157:Transcription Factors; C066177:Ubx protein, Drosophila