Fig. 3. Epistatic analyses between nti, Notch and fng. In all figures, Wg expression is shown in purple and somatic clones that lack nti function, and/or that overexpress specific genes, are shown in green. Anterior is towards the left and dorsal is upwards. (A) nti somatic clones showed cell-autonomous loss of Wg expression. Higher magnifications of the clones at the DV border are shown in the insets. y w hs-flp/+; FRT^G13 nti/FRT^G13 tubP-GAL80; tubP-GAL4/UASGFP larva wing imaginal disc is shown. nti homozygous clones are shown by GFP fluorescence (green). (B) Cell-autonomous Wg ectopic expression was detected when an activated form of Notch was expressed in nti mutant cells (arrowhead) as in wild-type cells (data not shown), indicating that nti is not needed for Notch^ICD function. Genotype of the wing imaginal disc is y w hs-flp/+; FRT^G13 nti/FRT^G13 tubP-GAL80; tubP-GAL4/UAS-GFP UAS-N^act. Thus, GFP indicates nti homozygous cells overexpressing Notch^ICD. (C) Overexpression of Notch is associated with ectopic Wg expression near the DV boundary. The genotype is y w hs-flp/+; FRT^G13/FRT^G13 tubP-GAL80; tubP-GAL4/UAS-GFP UAS-Notch. GFP shows full-length Notch overexpressing cells. (D) Full-length Notch effect was suppressed in nti mutant cells, indicating that nti is epistatic to full length Notch receptor. The genotype is y w hs-flp/+; FRT^G13 nti/FRT^G13 tubP-GAL80; tubP-GAL4/UAS-GFP UAS-Notch. GFP shows nti homozygous cells overexpressed for full-length Notch. (E) Ectopic expression of fng in the ventral compartment of the wing imaginal disc is associated with ectopic Wg expression near the margin. The genotype is y w hs-flp/+; FRT^G13/FRT^G13 tubPGAL80; tubP-GAL4/UAS-GFP UAS-fng. GFP shows Fngoverexpressing cells. (F) Ectopic expression of fng in nti mutant cells had no effect on Wg expression, showing that Nti is essential for Fng function. The genotype is y w hs-flp/+; FRT^G13 nti/FRT^G13 tubPGAL80; tubP-GAL4/UAS-GFP UAS-fng. GFP shows nti homozygous cells overexpressing Fng.