Fig. 12.

Principal cell mesh knockdown in the adult Drosophila Malpighian tubule does not affect epithelial integrity and smooth septate junction (sSJ) organization. Transmission electron micrographs of 14-day-old adult female fly anterior tubule main segment epithelial cells. Compared with control tubule main segment (w;tub-GAL80^ts20/+;c42-GAL4/+; A and B), the morphology of the main segment tubule epithelium of 14-day adult principal cell mesh knockdown (w;tub-GAL80^ts20/UAS-mesh^RNAi;c42-GAL4/+) is intact (E and F). Similarly, the sSJs between the principal cells of mesh knockdown tubule main segments (G, G′, H, and H′) appear normal with parallel plasma membranes and ladderlike septa (triangles in insets in G′ and H′) compared with control tubule sSJs (C, C′, D, and D′, triangles in insets in C′ and D′). Amv, apical microvilli; Bi, basal infoldings; mt, mitochondria; Nc, nucleus; PC, principal cell; RNAi, RNA interference; SC, stellate cell. Three samples per genotype were examined. Scale bars, 5 μm (A–C, D, E, F, F′, G, and H), 500 nm (C′, D′, G′, and H′).