In dlg12/dlg15 flies the border follicle cells have much reduced polarity. Delamination of these cells is delayed, but their migration is accelerated.
dlg12/dlg15 animals are viable and have completely normal egg chambers at 18oC. After 6 hours at 25oC, follicle cells exit the follicular epithelium and intermingle with germ cells at the anterior and posterior poles of the egg chamber. Cells that remain in the epithelium retain their polarised characteristics, whereas those that have exited the epithelium have an apolar morphology. Nurse cells extend processes to meet the invasive follicle cells, and the oocyte elongates to contact the cells. Follicle cells at the anterior and posterior ends of the egg chambers preferentially incorporate BrdU. Follicle cells do not have an invasive phenotype in females with homozygous dlg15 clones in the germ cells and follicle cells.
The lethal period is during the late pupal phase.