Figure 6

Specificity of bimolecular fluorescence complementation (BiFC) in the Drosophila embryo . (a) BiFC in live embryos expressing VCA and VNE either alone or with the parental wild type abdominalA (AbdA) protein (combination 1), as indicated. (b-c) Abolishing DNA binding of AbdA and extradenticle (Exd) abolishes heterodimeric complex formation. (b) Electrophoretic mobility shift assays (EMSAs) with wild type or homeodomain (HD)-mutated AbdA and Exd fusion proteins were performed on the Dll consensus probe [32]. The HD mutation in one partner strongly affects the heterodimeric complex formation (green arrowhead), while no complex is formed when both partners are mutated. The grey arrowhead indicates AbdA monomer binding. (c) BiFC analysis in embryos expressing various combinations (numbered 1 to 3) of wild-type or HD-mutated fusion proteins, as indicated. All fusion proteins were expressed with the abdA-Gal4 driver, and quantifications were performed in stage 10 embryos. See also Additional File 5. Diagrams in (a) and (c) are boxplot representations of the statistical quantification of the surface and intensity of fluorescent signals measured for each indicated combination (numbers in abscises) in the whole embryo.