In addition to the techniques described above, other techniques, including RNA-targeting CRISPR associated protein 9 (RCas9) , RNA-mimics of GFP-based systems , and sequence-specific Pumilio-based probes , have been developed for visualization of subcellular localization and trafficking of specific RNA molecules based on ensemble fluorescence measurement. Further work is required to explore their potential for imaging RNA transcripts in living cells at the single-molecule level.