Quantitative data for nuclear Dorsal, extracted from cycle 14 Drosophila embryos that were fixed and processed for immunohistochemistry with anti-Doral and anti-GFP antibodies as in [17, 29].

All embryos were processed concomitantly and arranged in a microfluidics device [65] for transversal slice image capture in a confocal microscope. After image capture, Nuclear fluorescence levels were extracted based on a Matlab routine as in [17,29,66], with the nuclei identified by DAPI staining, and arranged along the DV axis to generate half Gaussian curves. In the following sheets, nuclei are depicted according to their position along the dorsal (D) ventral (V) axis. (XLSX)