cil-1 functions cell autonomously in PVD to regulate ER morphology. (A) Schematic drawing of PVD dendrites and ER pattern. Note that the ER tubules invade some, but not all, dendritic branches in the PVD. PVD dendrites are divided into three different segments: posterior, proximal, and distal dendrites. Based on the ER branch morphology, ER tubules are divided into three types (I, L, and T) to indicate whether the ER tubules invade just the secondary or tertiary branches. (B) Representative confocal images of transgenic animals expressing a PVD neuron marker ser-2Prom3::mCherry (PVD::mCherry) and an ER resident protein ser-2Prom3::GFP::SP12 (PVD::GFP::SP12) simultaneously. Note that the ER tubules in the branches are reduced in the cil-1 mutant. This defect is restored by reexpresssion of CIL-1 in PVD neurons (PVD::CIL-1). Arrowhead represents an ER branch. Scale bar: 10 µm. (C) Quantification of PVD proximal region ER branches. *, p < 0.05; **, p < 0.01; n.s., not significant by one-way ANOVA. Error bars indicate SEM. n = 40 for each genotype. (D) ER morphology in PVD cell body revealed by SIM imaging. The images are single confocal slices crossing the nuclear envelope at approximately its equatorial region. A roughly concentric circle (red) of 4.6 µm in diameter was drawn around the nucleus. The number of crossings between the red circle and ER tubules was counted. Scale bar: 5 µm. (E) Quantification of the number of crossings between the red circle and ER profiles in cells of the various genotypes. The number of crossings reflects the complexity of the ER. ***, p < 0.001; n.s., not significant by one-way ANOVA. Error bars indicate SEM. n > 48 for each genotype.