The RFX-type transcription factor DAF-19 regulates sensory neuron cilium formation in C. elegans

Many types of sensory neurons contain modified cilia where sensory signal t ransduction occurs. We report that the C. elegans gene daf-le encodes an RF X-type transcription factor that is expressed specifically in all ciliated sensory neurons. Loss of daf-19 function causes the absence of cilia, resul ting in severe sensory defects. Several genes that function in all ciliated sensory neurons have an RFX target site in their promoters and require daf -le function. Several other genes that function in subsets of ciliated sens ory neurons do not have an RFX target site and are not daf-19 dependent. Th ese results suggest that expression of the shared components of sensory cil ia is activated by daf-19, whereas cell-type-specific expression occurs ind ependently of daf-19.