Protocol for electron microscopy of Drosophila photoreceptor cells

Summary In Drosophila , mutations in genes that prevent normal Ca 2+ influx after light stimulation usually cause light-dependent retinal degeneration or neurodegeneration, detectable by defects in eye morphology. Here, we present a protocol based on electron microscopy (EM) to observe the morphological structure of photoreceptor cells in Drosophila . We detail how to fix, dehydrate, embed, and polymerize compound eye samples, followed by sectioning, post-staining, and image acquisition, to assess the eye morphology at the ultrastructural level. For complete details on the use and execution of this protocol, please refer to Gu et al. (2020) .