A Discrete Model of Drosophila Eggshell Patterning Reveals Cell-Autonomous and Juxtacrine Effects
Figure 5
(A) Schematic dorsal view of the follicular epithelium, showing the 12 regions defined by combinations of input levels: Grk (4 levels, 0 to 3), Dpp (2 levels, 0 and 1), and Mid (2 levels, 0 and 1). (B) Final patterns before and after Grk extinction and description of the stable fates (F1 to F8). In regions R1 to R12, cells may adopt one of eight fates (F1 to F8) according to the values of the genetic network components (dpERK, Mirr, Pnt, Rho, Aos and Br; see also Supplementary Figure S1). The left diagram shows the final patterns obtained before and after Grk extinction (see Figure 4). Each row of the table describes the expression state of each component for a given fate. (C) Reachability analysis under the asynchronous update. In each region, we simulate the behavior of a naive cell inserted into the epithelium in its configuration just before the Grk extinction (the position of insertion determines the input values) and determine which stable state is reached (yellow arrows). The fate adopted by the cell follows the color code indicated in panel B. Upon Grk extinction, the simulation starts from a cell carrying the cell fate of the previous phase with now Grk levels set to 0, possibly leading to a new cell fate (grey arrows). In a few cases, more than one solution is attainable, such as in R5, R6 and R7. Full arrows represent trajectories towards fates matching the wild type situation, and dotted arrows indicate trajectories leading to alternative fates: e.g in R6 and R7, in addition to F5, the Br expressing pattern F8 is also reachable, unless a delay is assigned to Pnt (see text).