Figure 4.

(A) PNG and PLU exist in a large complex in Drosophila embryo extracts. Wild-type embryo extracts were fractionated on a sucrose density gradient, and fractions were analyzed by immunoblotting using anti-PNG and anti-PLU anti-bodies. Arrows indicate peak fractions of various molecular weight standards run in parallel. (B) PNG and PLU interact with a 1:1 stoichiometry. Combinations of recombinant baculoviruses used to infect Sf9 cells are shown above each lane. GST-PLU complexes were purified from Sf9 extracts using glutathione beads. Eluted proteins were resolved by SDS-PAGE and visualized by staining with GelCode Blue. As a negative control, recombinant GST (lane 3) was also purified from Sf9 extracts.