Figure 4. UPF1_LL overcomes translocation inhibition by PTBP1.

1. Scheme of the fluorescence‐based unwinding assay to monitor UPF1 translocation in real‐time (Fritz et al, 2020). An RNA substrate harboring a high‐affinity PTBP1 binding site is incubated with highly purified UPF1ΔCH in the absence and presence of equal molar amounts of highly purified PTBP1. Upon the addition of ATP, UPF1 translocation results in a decrease in fluorescence due to displacement of a labeled, duplexed oligonucleotide and subsequent quenching by a trap strand.
2. UPF1_SLΔCH translocation along an RNA substrate harboring a high‐affinity PTBP1 binding site in the absence and presence of PTBP1. Time to 50% unwound and relative total % unwound at end of assay (1,200 s) are indicated. Results of four technical replicates are shown for each dataset and represent at least three independent experiments. Shaded region indicates SD.
3. Results as in (B) but with UPF1_LLΔCH.

Source data are available online for this figure.