Live-cell single RNA imaging reveals bursts of translational frameshifting

Kenneth Lyon; Luis U. Aguilera; Tatsuya Morisaki; Brian Munsky; Timothy J. Stasevich

According to our best-fit model, pauses always occur at the frameshift sequence, with longer pauses associated with frameshifting RNA compared to non-frameshifting RNA. Pausing in and of itself is therefore only a weak predictor of frameshifting, as others have shown (Kontos et al., 2001; Tu et al., 1992) . Nevertheless, the longer pauses associated with frameshifting suggest the frameshift sequence can adopt more than one The copyright holder for this preprint (which was not peer-reviewed) is the author/funder. . https://doi.org/10.1101/478040 doi: bioRxiv preprint an elevated ribosomal occupancy as far back as ~400 codons from the FSS, a length that coincides almost perfectly with the length of the FSS-upstream sequence in HIV-1 gagpol. This is not unprecedented, as ribosome profiling experiments have also found evidence for relatively high ribosomal densities as far back as the start codon of the gag protein (Napthine et al., 2017) . These data suggest the strength of the HIV-1 pause may have evolved to on occasion produce the longest possible traffic jams. As clearance of these jams takes time, frameshifting can persist on RNA for hours despite a global shutdown of translation initiation. In effect, the jam acts like a battery that continually fuels the Beyond the imaging of HIV-1 translational frameshifting, the multi-frame tag can now be used in a variety of other contexts. For example, it can immediately be used to investigate frameshifting dynamics along other viral RNA sequences, as well as frameshifting thought to occur along endogenous human mRNA (Cardno et al., 2015) .