Fig. 7. JAK pathway function affects epithelial follicle cell differentiation. Loss of hop (A) or Stat92E (B-D) in mosaic animals alters epithelial cell fates. (A) In mutant clones (marked by loss of Ub-nGFP in green) generated 3 days before dissection, only cells of early stage chambers of the vitellarium maintain strong Fas III (red) expression (arrowhead). A mutant clone in a late stage chamber of the same ovariole retains little Fas III (arrow). Interestingly, some mutant cells in stage 7 or later chambers maintain Fas III in part of a clone (B-D). Typically the Fas III-positive cells are at the clonal boundary, adjacent to wild-type cells. Moreover, the Fas III-positive cells are almost always close to the terminus of the egg (asterisks).