Direct regulation of <i>sna-rg</i> by STAT.

(A) Representation of the minimal sna-rg R2P2 subfragments indicating the location of the putative STAT (pink crosses) and Hox-Exd-Hth DNA binding sites (black boxes). Mutated STAT binding sites are represented with a red X over the pink cross. (B) sna-rg R2P2-GFP expression. (C) No GFP expression is observed in A1 nor in A2 constructs (D). Gland expression is observed when A1 is joined to the A2 proximal half (E) or when A1 is joined to the A2 distal half (F). (G) A1 fused to a 20bp from the vvl1+2 enhancer containing a functional STAT binding site. (H) A1 fused to the same 20bp fragment where the STAT binding site has been mutated. (I-K) Embryos carrying both the sna-rg-R2P2-GFP-PH (green) and the sna-rg-R2P2-STATmut Histone2B-RFP-GFP-PH (red and green) constructs. Red nuclear expression is not observed at early stage 11 (I) but can be detected later exclusively in the CA (J). Df(1)os1A embryos lacking all Upd ligands (K) do not express sna-rg-R2P2-STATmut mCherry-GFP-PH. Black arrows in (E-G) point to the CA/PG gland primordia, red arrows to ectopic expression outside the glands. Scale bars 50 μm.