RT Journal Article SR Electronic T1 Genetically targeted 3D visualisation of Drosophila neurons under Electron Microscopy and X-Ray Microscopy using miniSOG JF bioRxiv FD Cold Spring Harbor Laboratory SP 070755 DO 10.1101/070755 A1 Julian Ng A1 Alyssa Browning A1 Lorenz Lechner A1 Masako Terada A1 Gillian Howard A1 Gregory S. X. E. Jefferis YR 2016 UL http://biorxiv.org/content/early/2016/08/22/070755.abstract AB Large dimension, high-resolution imaging is important for neural circuit visualisation as neurons have both long- and short-range patterns: from axons and dendrites to the numerous synapses at their endings. Electron Microscopy (EM) is the favoured approach for synaptic resolution imaging but how such structures can be segmented from high-density images within large volume datasets remains challenging.Fluorescent probes are widely used to localise synapses, identify cell-types and in tracing studies. The equivalent EM approach would benefit visualising such labelled structures from within sub-cellular, cellular, tissue and neuroanatomical contexts.Here we developed genetically-encoded, electron-dense markers using miniSOG. We demonstrate their ability in 1) labelling cellular sub-compartments of genetically-targeted neurons, 2) generating contrast under different EM modalities, and 3) segmenting labelled structures from EM volumes using computer-assisted strategies. We also tested non-destructive X-ray imaging on whole Drosophila brains to evaluate contrast staining. This enables us to target specific regions for EM volume acquisition.