Phosphate backbone epitranscriptomics: Discovery of natural RNA phosphorothioates and their writer machinery.
Over 150 modifications expand the RNA alphabet, yet all known natural modifications occur on nucleobases or ribose sugars, with none identified on the phosphate backbone. In contrast, phosphorothioates (PSs), in which a non-bridging phosphate oxygen is replaced with sulfur, are central to RNA therapeutics but have neve...