(A) Cartoon showing the PVD dendritic arbor. The dash-boxed region is magnified to show the PVD soma (asterisk), axon, primary dendrite (1°), secondary dendrite (2°), tertiary dendrite (3°) and quaternary dendrite (4°). (B) Representative wild type (WT) dendritic morphology of PVD neuron expressing membrane associated mCherry (wyIs581). Starting from the cell body, the anterior and the posterior sections of the primary dendrite are divided into 8 and 4 equal segments, respectively, indicated by dashed lines. Anterior, left; dorsal, top. Asterisk, cell body; arrowhead, quaternary (4°) dendrite. Scale bars, 50 μm. (C) Quantification of the number of quaternary (4°) branches in each segment in WT. The position of cell body is indicated by the black line. Error bars show mean ± s.e.m., n = 10. (D to G) Defective PVD dendritic morphogenesis in ire-1 (ok799) mutants (D and E) is rescued by expressing ire-1 cell-autonomously (F and G). (H and I) Representative dendritic morphology of FLP neurons labeled by cytoplasmic GFP in wild-type (H) and ire-1 (ok799) mutants (I). Asterisks, cell bodies; arrows, secondary branches; arrowheads, tertiary branches. Scale bar, 20 μm.