Msn functions cell-autonomously to promote follicle cell migration. (A) Overview of egg chamber structure. (B) Schematic for visualization of follicle cell migration. (C and D) msn-RNAi epithelia (n = 15) show migratory defects compared with control epithelia (n = 19). All imaging was performed on stage 6–7 egg chambers. (C) Stills from a time lapse (Video 1) of stage 6 control and msn-RNAi epithelia, in which a single follicle cell is monitored over time (blue and yellow dots). (D) Maximum intensity kymograph drawn through control or msn-RNAi follicle cells (dotted lines). (E) Maximum intensity kymograph drawn through wild-type (blue) and msn¹⁷² (yellow) cells in a mosaic epithelium (Video 2). (F) Stills from a time lapse (Video 3) of an msn-RNAi flipout clone (GFP). Bars: (C, E, and F; egg chamber images) 20 µm; (D and E; kymographs) 5 µm.