APOPTOSIS OF NURSE CELLS AT THE LATE STAGES OF OOGENESIS OF DROSOPHILA-MELANOGASTER

In Drosophila a remarkable feature of oogenesis is the regression of t he nurse cells after dumping their cytoplasmic contents into the oocyt e. We have studied the nature of this process at the late stages of eg g chamber development. In egg chambers DAPI staining shows highly cond ensed chromatin from stage 12 and TUNEL labelling shows DNA fragmentat ion up to stage 14. Gel electrophoresis of the end-labelled DNA, extra cted from isolated egg chambers at the same stages of development, sho ws a ladder typical of apoptotic nuclei. This provides evidence that, during Drosophila oogenesis, the nurse cells undergo apoptosis. Apopto tic nuclei have also been detected in dumping-defective egg chambers, indicating that the cytoplasmic depletion of nurse cells is concurrent with but apparently not the cause of the process.