Figure 3

Expression of Dlk1 inhibits Notch target genes and leads to ectopic sensory organ precursors. (A) Wild-type wing imaginal disc, Cut (red) is detected in a stripe along the d/v boundary. (B) Expression of SM-Dlk (green, arrows) leads to a slight reduction in Cut (red). (C,D) Expression of M-Dlk (green, arrows) inhibits Cut (red) expression. ptc::Gal4 is expressed in a slight gradient, barely detectable levels of DLK1 in the anterior of the domain are still sufficient to inhibit Cut. A few cells where Cut is induced ectopically are detected posterior to the DLK1 expression domain (arrowhead). D is a higher magnification of C, note that the M-Dlk is seen at the membrane of the expressing cells. (E,F) E(spl)mβ::CD2 expression in wild-type (E) and M-Dlk expressing disc. Arrows in F indicate the domain of M-Dlk expression where E(spl)mβ::CD2 is inhibited. (G,H) Senseless expression in wild-type (G) and M-Dlk expressing disc. Senseless expression is inhibited at the d/v boundary (arrows; characteristic of loss of Notch activity) and is expanded in the ventral and dorsal radius (arrowheads) indicative of ectopic sensory organ precursors.