Nuclear Trafficking and Export of Single, Native mRNPs in Chironomus tentans Salivary Gland Cells

: Real-time observation of single molecules or biological nanoparticles with high spatial resolution in living cells provides detailed insights into the dynamics of cellular processes. The salivary gland cells of Chironomus tentans are a well-established model system to study the processing of RNA and the formation and fate of messenger ribonucleoprotein particles (mRNPs). For a long time, challenging imaging conditions limited the access to this system for in vivo fluorescence microscopy. Recent technical and methodical advantages now allow observing even single molecules in these cells. We describe here the experimental approach and the optical techniques required to analyze intranuclear trafficking and export of single native mRNPs across the nuclear envelope.