Fig. 6. (A) Wild-type expression of PVF1 (red) in the oocyte and nurse cell cytoplasm at stage 9. (B,C) Clones of ectopic PVF1 expression in follicle cells of a stage 9 egg chamber showing expression of PVF1 in red (B) co-expressed with ß-galactosidase (green), which labels the clones (C). The broken lines show the outline of the egg chambers. (D-G) Classes of phenotypes observed after misexpression of PVF1, PVF2 or GRK. Egg chambers with clones of anterior follicle cells misexpressing one or more ligands (green, arrowheads). Singed staining labels the border cells (red, arrows). Representative examples of the four phenotypic classes are shown. (D) Class I: normal migration of the border cell cluster; an example of a UAS-Pvf1 egg chamber is shown. (E) Class II: the border cells fail to migrate away from the anterior pole and are adjacent to a clone of follicle cells misexpressing ligand; an example of a UAS-Pvf1 egg chamber is shown. (F) Class III: the border cells localize to the side of the egg chamber less than one nurse cell away from the anterior pole and adjacent to follicle cells misexpressing ligand; an example of a UAS-Pvf1;UAS-grk egg chamber is shown. (G) Class IV: the border cell cluster localizes to the side of the egg chamber at least two nurse cells away from the anterior pole, adjacent to a clone of cells misexpressing ligand; an example of a Pvf1¹⁶²⁴;UAS-Pvf1 egg chamber is shown. (Insets) Schematics of the stage 10 egg chambers represented in the fluorescent images, depicting the position of the border cells (red) with respect to the cells misexpressing ligand (green). The area indicated by the blue dashed box in the schematic outlines the anterior half of the egg chamber, which is shown at high magnification in the fluorescent images. Anterior is towards the left in all panels.