Self-Assembly of Intracellular Multivalent RNA Complexes Using Dimeric Corn and Beetroot Aptamers

DNA and RNA can spontaneously self-assemble into various structures, including aggregates, complexes, and ordered structures. The self-assembly reactions cannot be genetically encoded to occur in living mammalian cells since the double-stranded nucleic acids generated by current self-assembly approaches are unstable and activate innate RNA immunity pathways. Here, we show that recently described dimeric aptamers can be used to create RNAs that self-assemble and create RNA and RNA-protein assemblies in cells. We find that incorporation of five copies of Corn, a dimeric fluorogenic RNA aptamer, into an RNA causes the RNA to form large clusters in cells, reflecting multivalent RNA-RNA interactions enabled by these RNAs. Here, we also describe a second dimeric fluorogenic aptamer, Beetroot, which shows partial sequence similarity to Corn. Both Corn and Beetroot form homodimers with themselves but do not form Corn-Beetroot heterodimers. We thus use Corn and Beetroot to encode distinct RNA-protein assemblies in the same cells. Overall, these studies provide an approach for inducing RNA self-assembly, enable multiplexing of distinct RNA assemblies in cells, and demonstrate that proteins can be recruited to RNA assemblies to genetically encode intracellular RNA-protein assemblies.