Fig. 2. Non-reciprocal interdependence of E(z), Pcl and Phol for PRE binding. (A) Schematic of the bxd regulatory region of the Ubx gene. PCR-amplified regions are indicated below. (B-E) Quantitative ChIP results using (B) anti-E(z), (C) anti-Pcl, or (D) anti-Phol antibodies, or (E) no antibodies. Wing imaginal discs were dissected from the following larvae: Oregon R (WT); E(z)⁶¹ homozygotes [E(z)61]; PWIZ-Pcl/P{GAL4-da.G32} (Pcl RNAi); phol^81A; pho¹ homozygotes (phol; pho). (F) Western blot showing Pcl and E(z) levels in Oregon R (1), P{GAL4-da.G32}/+ (2) and PWIZ-Pcl/P{GAL4-da.G32} (3) wing imaginal discs.