Inhibiting both autophagy and caspases does not abolish nurse cell death in late stage egg chambers. Jeanne S. Peterson, Alla Yalonetskaya, Kim McCall. Dept Biol, Boston Univ, Boston, MA.

   During late oogenesis egg chambers degrade and eliminate their 15 nurse cells as part of normal development. This process of degradation involves at least two types of cell death, apoptosis and autophagy, as indicated by anti-caspase immunostaining, TUNEL and LysoTracker staining. In addition, mutations affecting either caspase dependent cell death or autophagy partially reduce nurse cell removal, leaving behind end stage egg chambers with persisting nurse cell nuclei (PNs). To determine whether apoptosis and autophagy work in parallel to degrade and remove nurse cells as is the case with salivary glands during the pupal stage (Berry and Baehrecke, 2007), we made mutants doubly affecting both caspases and autophagy and found no significant increase in the number of late stage egg chambers containing PNs nor in the number of PNs per egg chamber. This indicates that there is another form of cell death functioning in the ovary to remove all nurse cell remnants from late stage egg chambers. To examine this further, we are investigating the morphological changes that occur to nurse cells during developmental cell death. In particular, we have found that nurse cell nuclei show dramatic involutions, and the nuclear lamina persists until late in the process of cell death.