FIGURE 4.

Wingless is required for expression of distal tubule markers. (A) Counts of the number of Malpighian tubule cell nuclei expressing distal marker, Dachshund. Generally, for each embryo the number of nuclei staining with anti-Dac in a single anterior Malpighian tubule were counted. This was not possible in all genotypes depending on the morphology, and in this case the count was from a single tubule if discernible, or the entire mass of tubule cells if not. W ¹¹¹⁸ (control) n = 16. OrR (control) n = 10. CtB>λtop n = 20, p = 0.087. CtB > EGFR-DN n = 12, p < 0.00001***. CtB > pan∆N = 12, p = 0.000012***. CtB > arm ^S10 n = 16, p < 0.00001***. Wg ^1-17 n = 20, p < 0.00001***. Byn > pan∆N = 19, p < 0.00001*** (p = 0.81 comparing to wg ^1-17 ). Byn > arm ^S10 n = 7, p = 0.040*. Byn > Nrt-wg n = 13, p = 0.00070***. Cv-c ^M62 embryos n = 16, p < 0.00001*** (p < 0.00001*** comparing to wg ^1-17 ). Df(1)sc-B57 n = 20, p < 0.00001*** (p = 0.00018*** comparing to wg ^1-17 ). Stg ⁴ n = 22, p < 0.00001*** (p = 0.062 comparing to Df(1)sc-B57, p = 0.020* comparing to wg ^1-17 ). Nrt-wg n = 6, p = 0.28. N numbers represent number of embryos. p-values calculated using Mann-Whitney U test comparing to the w ¹¹¹⁸ control group, except where stated otherwise. (B–D) and (G–H) ∼Stage 16 embryos stained to show MpT nuclei (anti-Cut, brown) and the nuclei of cells from the distal MpT segment (anti-Dac, black, arrowheads). Arrows indicate MpTs, in cases where anti-Dac staining is absent. (E, F) ∼stage 16–17 embryos stained for cut and Irk3 mRNA. (B) Control embryo (w ¹¹¹⁸ ). (C) Homozygous wg ^1-17 embryo. (D) Byn-Gal4>UAS-pan/dTCF∆N embryo. (E) Control (w ¹¹¹⁸ ) embryo. (F) Homozygous wg ^1-17 embryo. (G) Byn-Gal4>UAS-arm ^S10 embryo. (H) Byn-Gal4>UAS-Nrt-wg embryo. Scale bars = 50 μm. Scale bar in H applies to (B–D), (G, H). Scale bar in F applies to (E, F).