FIG. 2.

Patterning of the dorsolateral eggshell appendage (DA)-forming cells. (a) Signaling through Epidermal growth factor receptor (blue) and Decapentaplegic (red) pathways combine to specify dorsal-anterior cell fates. Cells expressing Rhomboid (purple), a protease that activates epidermal growth factor ligands, will form the floor of the DA tubes, whereas cells that express high levels of the transcription factor Broad (white dots) will form the roof and sides of the DA tubes. (b) Crosssection of a stage 10B shows the outcome of patterning the epithelium: stretch cells (cut away, in green), nurse cells (purple), centripetal and dorsal midline cells (light gray), floor cells (red), roof cells (blue), oocyte (yellow). Modified from James and Berg⁷⁰ and Dorman et al.³⁸