a–d Activation of JAK/STAT pathway was detected by 10X STAT92E-GFP reporter in eye-antennal discs. a, c Significant increase in GFP level was observed in GMR-GAL4 driven mahe eye antennal disc when compared to the reporter line alone, indicating activation of JAK/STAT signaling (compare area in rectangle). b, d DAPI was used to mark the nucleus. e–l Gain of function clone of mahe displays enhanced Stat92E activity. Gain of function clones of mahe using UAS-HA-mahe flies were generated with FLP/FRT system in salivary gland. f, j GFP positive and non-GFP cells mark mahe gain-of-function clones (marked with arrow) and wild-type cells (marked with arrowhead), respectively. e Level of Stat92E the transcription factor for JAK/STAT signaling was enhanced in mahe gain-of function somatic clones when compared to wild-type neighboring cells. i Clonal area marked with GFP positive cells, shows elevated level of Mahe in the gain-of-function clones. g, k DAPI was used to mark the nucleus. h, l Fourth column represents merged image with DAPI staining. m Graph represents Stat92E intensity per unit area which shows marked enhancement in the level of Stat92E in nucleus and cytoplasm, in mahe overexpressing clones when compared to neighboring cells. One-way ANOVA. n, n′ Ectopic expression of mahe results in rough eye phenotype. o, o′ and p, p′ mahe induced rough eye phenotype was rescued by H99 and hid mutant, but not with rpr and grim mutants (q, q′ and r, r′). s Real time PCR showed a threefold increase in hid transcript levels upon ectopic expression of mahe, while downregulation of JAK/STAT pathway by stat92E-RNAi rescued the hid levels. One-way ANOVA. Scale bar in 50 µm (a–d, e–l). Genotypes (a, b) w/+; 10X STAT-GFP/+, GMR-GAL4/+ (c, d) w/+; 10X STAT-GFP/+; GMR-GAL4, UAS-HA-mahe/+ (n) w/+; +; GMR-GAL4,UAS-HA-mahe/+ (o) w/+; +; GMR-GAL4,UAS-HA-mahe/H99 (p) w/+; +; GMR-GAL4,UAS-HA-mahe/hid05014 (q) w/+; +; GMR-GAL4,UAS-HA-mahe/rpr87 (r) w/+; +; GMR-GAL4,UAS-HA-mahe/grimC15E. One-way ANOVA * P < 0.05, ** P < 0.01, *** P < 0.001.