The localization of some IFT components is affected in nphp-4 mutants. Amphid channel cilia expressing various IFT reporters in wild-type and nephrocystin mutants. In nephrocystin mutants, CHE-11∷GFP (a1–a4), CHE-2∷GFP (not depicted), and OSM-5∷GFP (c1–c4) appear normal. In contrast, complex B polypeptide OSM-6∷GFP is dimmer in amphid cilia and fails to enter or is restricted from the distal segment of nphp-4 and nphp-1;nphp-4 (b1–b4). In b3, “Dim distal” segments are observed and in b4, distal segments are not visible, indicated by “No distal.” See Fig. S3 for qualitative analysis of dim cilia. CHE-13∷GFP (d1-d4) is normal in nphp-1 mutants (d2) but is absent from the distal segment in 26% of nphp-4 animals (d3 and d4). d3 is an example of amphid channel cilia that appeared normal, and d4 depicts amphid channel cilia lacking distal expression of CHE-13∷GFP. BBS-7∷GFP is also restricted from nphp-4 and nphp-1;nphp-4 distal segments (e3 and e4) and slightly aggregates in middle segments (e3, arrow). In nphp-4, BBS-8∷GFP (f1–f4) was dim and barely detectable and “dim in cilia,” although clearly present in TZs (f3 and f4, arrows). Localization of both DYF-1∷GFP (g1–g3) and DYF-13∷GFP (g1–g4) appears normal. OSM-3∷GFP is considerably dimmer in nphp-4 and nphp-1;nphp-4 amphid cilia with bright signal in the distal dendrite (i3 and i4, arrowheads). KAP-1∷GFP localization also appears normal, with no distal localization (j1–j4). Similar results were observed in phasmid cilia (not depicted). Lateral view of the lips is shown, the anterior is to the top of each panel. Bar, 10 μm.