Loss of tissue upon PKD RNAi. A) Schematic drawing of a wing imaginal disc, highlighting the antero-posterior (a/p) boundary. Oval represents presumptive wing blade. B) Expression domain of ptc-Gal4 along the a/p boundary, visualized by overexpression of GFP (green). C) RNA interference was induced by overexpression of UAS-dsPKD114-5 with ptc-Gal4 and caused detectable reduction of PKD protein accumulation (red; arrow). D) Control wing; the antero-posterior boundary is marked by a dotted line; the distance between third and fourth longitudinal veins is highlighted by a double-headed arrow. E) PKD RNAi along the antero-posterior boundary results in tissue loss (compare double-headed arrow with control in D) and in a folded wing with uneven texture. F – J) Analysis of cell proliferation and apoptosis in wing discs of ptc > dsPKD larvae (G, G', I, K) versus control discs (F, F', H, J). Antibody staining against engrailed (red; F', G', J, K) highlights the border of the posterior compartment. Scale bar, 100 μm. F, F') Control wing disc stained for activated Caspase 3 (green) to label apoptotic cells and for engrailed (red) to mark the border of the posterior compartment (arrowhead). G, G') A likewise stained wing disc of ptc > dsPKD larvae reveals an enrichment of activated Caspase 3 along the antero-posterior boundary (arrow). H) BrdU-incorporation (green) was visualized to reveal replicating cells in a control disc. Note the zone of non-proliferation along the dorso-ventral boundary as well as a slight decrease of S-phase cells along the antero-posterior boundary (arrowhead). I) In contrast to the control, wing discs of ptc > dsPKD larvae show a decrease of BrdU incorporation all along the ptc-stripe (arrows) indicating a downregulation of cell division. J) Control wing disc stained for phospho-Histon H3 (green) to label mitotic nuclei; the posterior compartment is highlighted in red (arrowhead). K) A likewise stained wing disc of a ptc > dsPKD larva shows no overt difference in mitotic cells compared to control neither with regard to total number nor along the antero-posterior border (arrow). Genotypes are: B) ptc-Gal4/+, UAS-GFP/+; C, E, G, G', I, K) ptc-Gal4/+, UAS-dsPKD6-4 /UAS-dsPKD6-4; D, F, F', H, J) ptc-Gal4/+.
Maier et al. BMC Developmental Biology 2007 7:74 doi:10.1186/1471-213X-7-74