Joubert syndrome gene fam149b1 homolog, xbx-4 , is required for multiple sensory behaviors.

Many cells require cilia to receive environmental signals. Mutations in the ciliary gene fam149b1 result in the ciliopathy Joubert syndrome. The C. elegans homolog of fam149b1 , xbx-4 , is required for normal cilium structure. We found that loss of XBX-4 hinders multiple cilium-mediated behaviors. xbx-4 mutants display mild defects in male mating and nose touch behaviors and dramatic changes in social feeding. Unexpectedly, xbx-4 mutants increased reversal behavior in response to ethanol, a control stimulus used in olfactory assays. Variation in the magnitude of phenotypes for different neurons is consistent with known cell-specific impacts of XBX-4 loss on cilium structure.