This system, which we used previously to mark cyst lineage cells that arise from transdifferentiating hub cells upon knockdown of Rbf (Greenspan and Matunis, 2018), marks the nuclei of cells currently expressing Gal4 with a red fluorescent protein (RFP) and permanently marks the nuclei of any cells originating from the Gal4-expressing cells with a green fluorescent protein (GFP). Here, LGALS4 is linked to cyst.