<i>cuti-1(RNAi)</i> worms display defects in seam cell function and epithelial integrity.

<p>A, B. Confocal micrographs of the seam cell boundaries of adult <i>control(RNAi)</i>;<i>dlg-1::gfp</i> and <i>cuti-1(RNAi)</i>;<i>dlg-1::gfp</i> worms respectively. <i>cuti-1(RNAi)</i>;<i>dlg-1::gfp</i> worms either failed to form a seam cell syncytium or failed to maintain the cell-cell contact between seam cells (B). C, D. Scanning electron micrographs of N2 worms fed control dsRNA and <i>cuti-1</i> dsRNA respectively. The lateral alae secreted by the underlying seam cells in <i>cuti-1(RNAi)</i> worms were bifurcated (arrow) (D). E, F. Confocal micrographs of adult <i>control(RNAi)</i>;<i>col-19::gfp</i> and <i>cuti-1(RNAi)</i>;<i>col-19::gfp</i> worms respectively. COL-19 is an adult-specific collagen that is expressed in the lateral alae (asterisks) and circumferential annuli (double-headed arrows) of the cuticle (E). Using COL-19 as a marker, the alae (asterisks) and annuli (double-headed arrow) appear highly disorganized in <i>cuti-1(RNAi)</i>;<i>col-19::gfp</i> adults (F). G. Nomarski micrograph of a <i>cuti-1(RNAi)</i> L4 worm showing vacuolation of the hypodermis (arrow). H. Scanning electron micrograph of an adult <i>cuti-1(RNAi)</i> worm showing a protruding vulva. I, J. Fluorescent micrographs of the anterior region of N2 adults fed control dsRNA and <i>cuti-1</i> dsRNA respectively. Worms were soaked in a 1 µg/ml solution of Hoechst 33258 (Sigma) for 15 mins. Hoechst 33258 is a membrane impermeable dye that fluoresces when bound to DNA. <i>Control(RNAi)</i> worms do not show fluorescence of nuclei when soaked in a solution of Hoechst 33258 (I). In contrast, nuclei of <i>cuti-1(RNAi)</i> worms fluoresce because of reduced barrier function of the cuticle and hypodermis (J). Scale bars 50 µm, except in C and D where scale bars 10 µm.