Abstract
longitudinals-lacking (lola) was identified in Drosophila as a gene encoding several alternatively spliced transcription factors involved in axon guidance. Here we report that lola also plays a critical role in programmed cell death in the ovary. lola mutant germline clones show a high percentage of egg chambers with nurse cell nuclei persisting past stage 13, indicating a block in developmental nurse cell death. Mutants also show a disruption in the induced programmed cell death that occurs during mid-oogenesis in response to starvation. Further characterization revealed that lola germline clones exhibit abnormal nuclear organization which becomes increasingly severe with age. Chromatin appears diffuse and fails to condense properly or undergo DNA fragmentation in dying nurse cells. Masses of nuclear material accumulate in the ovaries of older flies containing lola germline clones. We propose that lola is necessary for complete chromatin condensation which occurs during programmed cell death in the ovary. Alleles differed in the strength of their phenotypes but interestingly, the severity of their ovarian phenotypes was independent of the strength of their neuronal phenotypes, suggesting a differential requirement for individual lola isoforms in the ovary and nervous system.
