Figure 7.

Disinhibition of Su(dx) by Drosophila Dishevelled. (a) Western blot of His pull-downs from HEK293T cells co-transfected with His-Ub, wt or catalytically inactive HA-WWP2 or HA-Su(dx), and wt or polymerization-deficient Flag-Dsh, as indicated above panels, revealing efficient disinhibition of both human and fly E3 ligase by Drosophila Dsh. (b–f) Fly wings after GAL4-mediated overexpression of Dsh and/or Su(dx) in the wing disc primordium during the third-larval instar (with MS1096.GAL4), as indicated in the panels; note the excess of vein material (arrows) after co-expression of polymerization-competent (DshM7) but not polymerization-deficient Dsh (DshM1), reflecting attenuated Notch signalling. Only mild vein defects are observed if Dsh or Su(dx) are overexpressed on their own. (g–i) Early pupal imaginal discs bearing the Notch reporter E(spl)mβ1.5-lacZ, co-stained for lacZ (green) and DAPI (red) after co-expression of Dsh and Su(dx) as in (b), revealing strong defects in vein specification after co-expression of DshM7 but not DshM1. Scale bar, 100 µm.