The divergent TGF-β ligand Dawdle utilizes an activin pathway to influence axon guidance in Drosophila

摘要: Axon guidance is regulated by intrinsic factors and extrinsic cues provided other neurons, glia target muscles. Dawdle (Daw), a divergent TGF-β superfamily ligand expressed in mesoderm, required for embryonic motoneuron pathfinding Drosophila . In daw mutants, ISNb SNa axons fail to extend completely are unable innervate their targets. We find that Daw initiates an activin signaling pathway via the receptors Punt Baboon (Babo) signal-transducer Smad2. Furthermore, mutations these components display similar axon defects. Cell-autonomous disruption of receptor suggests Babo motoneurons rather than muscles or glia. Ectopic expression can rescue phenotype, but has no deleterious effects. Our results indicate functions permissive manner modulate enable growth cone response restricted cues, support novel role guidance.