C. elegans daf-6 encodes a patched-related protein required for lumen formation.

Sensory organs are often composed of neuronal sensory endings accommodated in a lumen formed by ensheathing epithelia or glia. Here we show that lumen formation in the C. elegans amphid sensory organ requires the gene daf-6. daf-6 encodes a Patched-related protein that localizes to the luminal surfaces of the amphid channel and other C. elegans tubes. While daf-6 mutants display only amphid lumen defects, animals defective for both daf-6 and the Dispatched gene che-14 exhibit defects in all tubular structures that express daf-6. Furthermore, DAF-6 protein is mislocalized, and lumen morphogenesis is abnormal, in mutants with defective sensory neuron endings. We propose that amphid lumen morphogenesis is coordinated by neuron-derived cues and a DAF-6/CHE-14 system that regulates vesicle dynamics during tubulogenesis.