Fig. 2.

Smad2 RNAi produces tissue-autonomous wing disc widening. (A-I′) For each GAL4 driver, GFP reporter shows late L3 wing disc expression (A-I). mGFP indicates membrane-localized GFP. The effect of Smad2 RNAi is shown in the corresponding prime panels (A′-I′) with the W/H ratio presented as the mean for the indicated number of samples. Statistical significance of a one-tailed t-test for widening is indicated. *P<0.05, ***P<0.001. n.s., not significant. da-GAL4 (A) is a constitutive driver. A9 (B) and 71B (C) have restricted disc expression but caused no widening. C765 (D) is expressed in late L3 but caused minimal widening. sd (E) and 32B (F) are expressed in the entire disc and caused widening. sd-GAL4 is strongest in a central region including the wing blade with weaker expression in the remainder of the disc (see cells in upper left area in B and E for negative and weak GFP expression). tsh and nub expression domains produced widening only when used together (G-I). Wing discs are oriented with the distal end up and the anterior to the left. Confocal images shown except panels D, G, H and I, which show wide-field images. Scale bars: 100 μm.