Figure 2. Stat92E is critical for hinge development.

(A) Expression of the 4xdSTAT-lacZ reporter in the adult wing hinge (blue) shows that JAK/STAT pathway activity remains active in the hinge until adulthood.

(B) Stat92E clones lead to loss of hinge structures (arrow) resulting in a wing blade that connects directly to the thorax. Clones are unmarked in the adult.

(C, D) Stat92E activity (10xSTAT-GFP, green) is largely overlapping with Hth (blue) in an early (C) and middle third instar wing disc (D) in the hinge. However, Hth is expressed in the notum (C′, D′, arrows) whereas 10xSTAT-GFP is not (C″, D″, arrows). Wg is red is C and D. C′, D′ are single channels for Hth; C″, D″ for 10xSTAT-GFP.

(E, F) Hth protein (blue in E and magenta in F) is slightly increased in Stat92E that lack GFP in early (E) and late third instar (F) discs. Vg is red is E. Arrows in E′ and F′ indicate regions of elevated Hth protein. E′, F′ are single channels for Hth.

(G) Hth (red, arrow in G′) is not altered by ectopic activation of the JAK/STAT pathway in Hop flip-out clones residing in the notum (labeled actin≫hop, green). G′ is single channel for Hth.

(H, I) Hth (blue) is repressed in Hop flip-out clones (green) residing in the notum (H′, I′, red arrows). Hth can be induced in an ectopic growth domain induced by a Hop flip-out clone residing next to the wg-lacZ (red) domain in the notum (I′, green arrow). H′, I′ are single channels for Hth.

(J) Stat92E activation (green, arrow in I′) is lost in a hth clone (indicated by the loss of LacZ (red)). J′ is single channel for 10xSTAT-GFP.

(K, L) Stat92E activity (green) can be upregulated by Hth flip-out clones (red, labeled actin≫hth) that reside in within the pouch (K′, arrows) and the notum (L′, arrow). K′, J′ are single channels for 10xSTAT-GFP.