Previous techniques could visualize active areas of transcription, but not give precise information about their shape and size. We imaged nascent RNA spatial accumulations, which we termed RNA nanodomains. We characterized the RNA nanodomains and revealed how they interact with active RNA Polymerase II, the main component of the transcription machinery, and in turn, with small chromatin clutches, one of the smallest units of organization of the DNA fibers.

Castells-Garcia et al. December 2021 Nucleic Acids Research 

https://academic.oup.com/nar/advance-article/doi/10.1093/nar/gkab1215/6462398?searchresult=1