Figure 5.

Dependence of Hh signaling on Ci-155 levels. (A–H) Narrowing of veins 3–4 in (A) fu; Su(fu)/+ controls is increased by heterozygosity for (C) Y14, (E) mago, or (G) Df(2L)BSC240, but these changes were (B, D, F, and H) suppressed by addition of a single copy of the gCi transgene. (I–P) In fu; Su(fu)/+ wing discs a single copy of the gCi transgene (I and M) increased ptc-lacZ expression and (J–O) suppressed inhibition of ptc-lacZ expression by (J and N) mago RNAi but (K and O) not by Srp54 RNAi. (L and P) Maximal ptc-lacZ intensity as a percentage of controls for fu; Su(fu)/+ wing discs expressing mago and Srp54 RNAi, with or without a gCi transgene, showing means and 95% C.I.s for n = 4 experiments. (Q and R) Loss of one copy of ci (R) reduced ptc-lacZ (red) expression in fu; Su(fu)/+ wing discs. (S–V) MARCM clones (marked by GFP, green) that lose a second chromosome gCi transgene in wing discs that are ci⁹⁴/+ and either (S and T) include a third chromosome gCi transgene or (U and V) express UAS-Ci with C765-GAL4. (S and U) Ci-155 levels (white) were increased greatly by UAS-Ci expression but were not affected by exchange of gCi transgenes. (T and V) Only excess Ci-155 from UAS-Ci decreased ptc-lacZ (red) and anterior En (white) expression at the AP border (yellow arrows). AP, anterior/posterior; En, engrailed; Hh, Hedgehog; Ptc, Patched; RNAi, RNA interference; wt, wild-type.