PRNP and prion disease: Fernandez-Funez et al. [238] showed that 30-day-old transgenic Drosophila melanogaster expressing hamster PrPC (Tg-PrP) exhibited several hallmarks of prion disease such as cytosolic vacuolation, nuclear condensation, spongiform degeneration in the brain and optic lobes, and vacuole formation on the cortex and neuropiles.