A membrane-less, cytoplasmic structure with a sponge-like appearance, found in female germ line cells of Drosophila and thought to function in the assembly and transport of materials required for RNA localization in the oocyte (q.v.). Sponge bodies generally consist of endoplasmic reticulum-like cisternae and vesicles embedded in an electron-dense matrix that is devoid of ribosomes. They contain RNA and protein, and are often surrounded by mitochondria. They are first observed during early oogenesis (q.v.) near the nurse cell nuclear membrane, change in morphology as development progresses, migrate through the ring canals (q.v.), and dissociate toward later oogenesis into smaller particles that are incorporated into the ooplasm (q.v.). Sponge bodies share morphological and functional characteristics with Balbiani bodies and mitochondrial clouds. See Balbiani body, cytoplasmic localization, mitochondrial cloud, nurse cells.
Subjects: Genetics and Genomics.