Inert Pepper aptamer-mediated endogenous mRNA recognition and imaging in living cells.

The development of RNA aptamers/fluorophores system is highly desirable for understanding the dynamic molecular biology of RNAs in vivo. Peppers-based imaging systems have been reported and applied for mRNA imaging in living cells. However, the need to insert corresponding RNA aptamer sequences into target RNAs and relatively low fluorescence signal limit its application in endogenous mRNA imaging. Herein, we remolded the original Pepper aptamer and developed a tandem array of inert Pepper (iPepper) fluorescence turn-on system. iPepper allows for efficient and selective imaging of diverse endogenous mRNA species in live cells with minimal agitation of the target mRNAs. We believe iPepper would significantly expand the applications of the aptamer/fluorophore system in endogenous mRNA imaging, and it has the potential to become a powerful tool for real-time studies in living cells and biological processing.