Expressed in both the amphid and tail ciliated sensory neurons. The 60 C. elegans CSNs present in an adult hermaphrodite worm were divided into 5 subgroups or anatomical regions including, neurons that reside in the amphids (region 1 = 24 CSNs: AWAL/R, AWBL/R, AWCL/R, AFDL/R, ASEL/R, ADFL/R, ASGL/R, ASHL/R, ASIL/R, ASJLR, ASKL/R, ADLL/R) or in the tail (region 2 = 5 CSNs: PHAL/R, PHBL/R, PQR), neurons surrounding the anterior bulb (region 3 = 24 CSNs: BAGL/ R, CEPVL/R, CEPDL/R, IL1L/R, IL2L/R, IL1VL/R, IL2VL/R, IL1DL/R, IL2DL/R, OLLL/R, OLQVL/R, OLQDL/R) or the posterior bulb (region 4 = 5 CSNs: ADEL/R, FLPL/R, AQR) of the pharynx, and neurons in the midbody region of the worm (region 5=2 CSNs: PDEL/R).
xbx-9 was detected in region 1 and 2.