Three-day-old Drosophila larva
A confocal image of a wing imaginal disc and the attached trachea from a 3-day-old Drosophila larva. All nuclei are marked in blue, while wingless- or patched-transcribing nuclei are shown in red. The green signal (dad-GFP) marks the nuclei that receive high levels of the morphogen Decapentaplegic (Dpp). Hamaratoglu et al. (e1001182) show that during growth the signalling activity of the Dpp morphogen scales with tissue size, and that this scaling requires the secreted feedback regulator Pentagone.
Image credit: Fisun Hamaratoglu/PLoS Biology, October 2011 issue
