RTKN-1 is required for actin integrity in the intestinal epithelia. (A) Domain architecture of RTKN-1a and allele information of rtkn-1(ok1404). Δ indicates deletion, and * indicates stop codon. (B) A diagram of C. elegans intestine and laser confocal scanning. (C–C′′) Confocal images showing GFP-Utrophin-CH–labeled actin structures in the intestinal cells. White asterisks in the panels indicate intestinal lumen. Box-and-whisker plots (n = 18 cells): 10–90th percentile; dots, outliers; red midline, median of WT; boundaries, quartiles. ***, P < 0.001 by Mann-Whitney test. (D and D′) Confocal images showing the colocalization between GFP-Utrophin-CH and RTKN-1-mCherry. Arrowheads indicate structures labeled by both GFP and mCherry. DAPI channel (blue color) indicates broad-spectrum intestinal autofluorescence. Pearson's correlation coefficient was calculated; error bar is 95% CI (n = 12 animals). (D′′) Line scan profile of GFP and mCherry signals. (E and E′) Live cell fluorescence images showing the dynamics of GFP-Utrophin-CH–labeled actin structures. A total of three intestinal cells of each genotype were sampled. Scale bars, 10 µm. MC, mCherry.