Clonable EM labeling

Abstract

Cell Biology Widespread use of the green fluorescent protein for protein localization at the light microscopy level has revolutionized cell biology. The search for a similar genetically encoded label for electron microscopy (EM) that could raise the resolution to the single-molecule level has not yet been successful. Jiang et al. developed a method for synthesizing 2- to 6-nm-diameter gold nanoparticles directly and specifically on individual cysteine-rich tags. This enables the unambiguous visualization of genetically tagged proteins in bacterial, yeast, and mammalian cells with single-molecule resolution. This approach holds promise in circumventing the difficulties of conventional EM immunolabeling and enables biologists to probe the ultrastructure of cells with greater ease. Nat. Methods 17 , 937 (2020).