Figure 4. Cortical Yki promotes growth via the Hippo pathway.

(A–D) Expression of both wild-type and membrane tethered Yki in the wing causes overgrowth. nub-Gal4 was used to drive expression of the indicated Yki transgenes in the wing blade. Representative images of female adult wings (cultured at 18 °C) of indicated genotypes are shown. Myr-Yki, Myr-Yki^ΔNH, and wild-type Yki all caused overgrowth.

(E–H) Myr-Yki-mediated overgrowth depends on myosin activity. Removing one dose of the regulatory light chain sqh (sqh^AX3) or the non-muscle myosin zip (zip¹) did not affect wing size on its own and partially suppressed the Myr-Yki overgrowth phenotype.

(I) Quantification of wing sizes for the indicated genotypes. Heterozygosity for sqh or zip suppressed the overgrowth induced by cortical, Myr-tagged Yki but not wild-type Yki. Data are represented as mean ± SEM. Asterisks represent statistical significance of the difference between selected groups (**** p<0.0001; n.s.: not significant [p > 0.05], One-way ANOVA and Tukey’s HSD test, n = number of wings).

(J–M) Ectopic expression of Yki transgenes in wing discs causes up-regulation of the Hippo pathway reporter ex-lacZ. hh-Gal4 was used to drive expression of Yki transgenes in the posterior compartment of wing discs. The boundary of expression is marked with a dotted yellow line.

(N–Q) Ectopic expression of membrane-associated Yki in wing discs causes increased nuclear localization of Yki-YFP. At the position of these optical sections, the nuclei are seen as dark circles surrounded by diffuse, cytoplasmically localized Yki-YFP in normal tissue (below the dotted yellow lines). ap-Gal4 was used to drive expression of Yki transgenes in the dorsal compartment (above the dotted lines) of wing discs. Myr-Yki and Myr-Yki^ΔNH, but not wild-type Yki, caused increased nuclear localization of Yki-YFP. Boxes denote regions shown in high magnification insets; white arrows indicate nuclei.

See also Figures S3 and S4.