The UAS constructs in the stocks below express proteins or protein domains tagged with miniSOG, a small photosensitizer engineered from the LOV2 domain of the Arabidopsis thaliana PHOT2 gene. Upon blue light illumination, the singlet oxygen generated by miniSOG locally converts diaminobenzidine to an osmophilic substrate for EM contrast. Using these stocks, miniSOG can be directed to the cytoplasm, cell membrane, actin fibers, mitochondria or synapses. Some of the miniSOG-tagged proteins are also tagged for epifluorescence microscopy. miniSOG can also be used for the chromophore-assisted light inactivation (CALI) technique: when miniSOG is fused to a protein of interest, blue-light dependent generation of singlet oxygen results in oxidation of susceptible amino acid residues. miniSOG has also been used as a light-dependent cell ablation tool.
The technique was described in Ng et al. (2016) “Genetically targeted 3D visualisation of Drosophila neurons under Electron Microscopy and X-Ray Microscopy using miniSOG” Scientific Reports 6: 38863.