APPL interacts with PCP signaling during MB development.

<p>(A–D) Structure of αβ neurons labeled with the FasII antibody. All the images are <i>z</i>-projections of confocal image stacks (scale bar, 50 µm). (A) Morphologically normal αβ neurons in a control adult brain. (B) Morphologically aberrant αβ neurons in <i>Appl^dw*/Y;;Fz^KD/+</i> adult brains. Loss of one copy of Fz in the <i>Appl</i>^−/− background increases moderately, but not significantly, the penetrance of β-lobe loss (indicated by the arrow) to 21% (<i>n</i> = 28); <i>p</i> value = 0.2166 calculated with G-test. (C) Morphologically aberrant α/β neurons in <i>Appl^d w*/Y;UAS-Fz-DN/+;P247Gal4/+</i> adult brains. Overexpression of a dominant negative form of Fz in the <i>Appl</i>^−/− background increases moderately, but not significantly, the penetrance of the phenotype to 18% (<i>n</i> = 28); <i>p</i> value = 0.4226 calculated with G-test. (D) Morphologically aberrant αβ neurons in <i>Appld w*/Y;Vang^stbm-6/+</i> adult brains. Loss of one copy of Vang in the <i>Appl</i>^−/− background increases the penetrance of the β-lobe loss up to 33% (<i>n</i> = 21); <i>p</i> value = 0.02304 calculated with G-test. (E) The graph shows the penetrance of β-lobe loss in genetic interaction experiments, normalized against the penetrance in the <i>Appl^dw*</i> background. (F, G) APPL and Vang localization during development in brain of flies <i>Act-Stbm-EYFP</i> expressing an EYPF tagged form of Vang under the control of the Actin promoter. Immuno-fluorescence analysis using anti-APP-Cterm (F, G in blue), anti-GFP (F′, G′ in green), and anti-FasII (F″, G″ in red) antibodies. The images are single confocal stacks (scale bar, 25 µm). The F‴ and G‴ panels show the merge of the FasII and GFP channel for the indicated samples. (F) At 48 h APF, Vang is broadly expressed along the MB β axons, where also APPL is expressed as indicated by the arrow. (G) At adult stage, the level of Vang detectable in the β axons is strongly reduced compared to the previously analyzed time point, while APPL is enriched in the MB neurons (as indicated by the arrow). (H) The graph shows the penetrance of the β-lobe loss in the <i>Appld^w*</i> flies overexpressing Dsh or Wnt5 (<i>p</i> value equal to 0.1287 and 0.0006692, respectively). Activation of Wnt-PCP signaling upon Wnt5 signaling rescues the β-lobe phenotype. ** Indicates a <i>p</i> value<0.001 calculated with G-test.