Figure 6. Cos2 reduces Ci-155 activity by binding to the CORD region.

(A–J) Wing discs from animals with one copy of the designated ci transgenes and alleles (together with ci⁹⁴) with clones (GFP, green, arrows) that lack (A–F) pka activity or (G–J) cos2 activity (arrowheads indicate AP border), showing (A’–J’) ptc-lacZ (red) and (A”–F”) Ci-155 (gray-scale). (A”–F”) Ci-155 levels were increased relative to neighboring anterior territory for all Ci proteins, but the increase was relatively small for (B”) Ci-ΔCORD, suggesting that processing outside the clones may be inefficient. By contrast, a large change was observed for Ci-ΔCDNΔCORD, suggesting very efficient processing. Scale bars are 40 μm. (K) Average intensity of ptc-lacZ in pka clones (red) and in cos2 clones (blue), as a fraction of AP border levels. Mean and SEM shown. Significant differences between values for a given genotype compared to those for crCi-WT, calculated by paired t-tests, are indicated for p<0.001 (*) and p<0.05 (#). Additionally, ptc-lacZ was significantly increased for gCi-ΔCORD versus gCi-WT in pka mutant clones (p<0.0001).