Fig. 1: Characterization of RG4 in human Tmprss2.

a RG4 potential and sequence conservation of Tmprss2 and Ace2 mRNA. The PQSs are predicted by QGRS-mapper. The conservation of the PQSs is assessed by UCSC genome browser. b Five top PQS sites in Tmprss2 mRNA. c CD spectrum (left panel), NMM (middle panel), and ThT (right panel) fluorescence emission spectra of PQS-675-WT, PQS-675-Mut, and PQS-1281-WT RNA under KCl or LiCl conditions. d FRET spectrum of PQS-675-WT and PQS-675-Mut RNA under KCl, LiCl, or PDS conditions. e, f CD (e) and FRET (f) melting measurements of PQS-675-WT and PQS-675-Mut RNA under KCl, LiCl, or PDS conditions. The melting temperature is shown in Supplementary Table 3. g Gel mobility shift assay of PQS-675-WT and PQS-675-Mut RNA under KCl or LiCl conditions. h BLI sensorgrams show the binding affinity of PDS with PQS-675-WT (top panel) and PQS-675-Mut (bottom panel) RNA under KCl condition. KD binding affinity, Ka binding rate, Kd dissociation rate. i Representative confocal fluorescence microphotographs of FAM-labeled RNA (green) and BG4 (red) treated with PDS or ASO (targeting PQS-675 RG4 site) in H1299 cells. The nuclei were stained with DAPI (blue). The colocalized FAM/BG4 foci are indicated by white boxes. Scale bars: 5 μm. j Quantification of FAM/BG4 foci number after FAM-labeled RNA transfection in h. For each condition, 20–30 cells were counted, and the standard error of the mean was calculated from a set of three replicates. Data are shown as mean ± SEM, n = 3. Two-tailed Student’s t test. Source data are provided as a source data file.