The paper introduce novel RNA-stabilized coat proteins, named dMCP and dPCP, engineered to overcome the challenge of high background noise in live-cell RNA imaging. These variants of the traditional MS2 and PP7 coat proteins are designed to rapidly degrade in the absence of their target RNA ligands, ensuring that only the RNA-bound proteins produce a fluorescent signal. Through techniques like circular permutation and degron masking, the researchers achieved up to a 63-fold increase in the stability of dMCP when bound to its cognate MS2 RNA. The new probes allow for sensitive, low-background visualization of single messenger RNA (mRNA) molecules in live cells, including transcripts undergoing different regulatory processes and those localized to distinct subcellular compartments. Furthermore, the orthogonal nature of dMCP and dPCP enables simultaneous, two-color tracking of different RNA species within the same cell.

References:

• Kuffner C J, Marzilli A M, Ngo J T. RNA-stabilized coat proteins for sensitive and simultaneous imaging of distinct single mRNAs in live cells[J]. Nature Methods, 2025: 1-12.