研究セミナー Real-time quantification of single RNA translation dynamics in living cells

Despite the key role translation plays in the central dogma of cell biology, the real-time translation of an RNA into protein has not yet been visualized in vivo. In this talk, I'll discuss a new technique my lab has developed to confront this problem. Using fluorescent antibody fragments (Fab), high-affinity epitope tags, and sensitive single-molecule imaging, we are able to visualize the emergence of nascent peptide chains from single, pre-marked RNA being translated in live cells. Our technique, which we call Nascent Chain Tracking (NCT), reveals elongation occurs at a rate of ~10 amino acids per second, with initiation occurring stochastically every ~30 seconds. Polysomes contain approximately 1 ribosome every 200-900 basepairs and are globular rather than elongated in shape. By developing two Fab pairs for imaging two different nascent proteins at the same time, we find polysomes do not interact much with each other, although a small fraction (~5%) form stable, co-moving complexes. The technology we have developed here will help pave the way for real-time quantification of translational dynamics in vivo.