Fig 1: The binding properties of RNA G-quadruplex-binding proteins revealed by FOREST.a Schematic of an rG4 structure. A canonical rG4 is formed by four repeats of sequential guanine nucleotides. A monolayer of rG4 is called a “G-tetrad” and consists of Hoogsteen base pairing. b Schematic of the FOREST-based characterization of rG4-binding proteins (BG4, CIRBP, and DHX36). c Average BG4-binding intensities comparing rG4 controls and human pre-miRNAs. The error bars indicate means ± s.d.; the p value was determined by the two-tailed Brunner–Munzel test. The data were calculated from the average of two independent experiments. d Scatter plots show correlations between the number of guanine nucleotides or G-scores for the binding intensity of rG4 controls (ten species). e The binding intensities of representative RNA structures; rG4 controls, triplet repeats, and pre-miRNA loops with Z-scores ≧ 3 for at least one protein. The size and color of a dot represent the Z-score of the binding intensity. f In vitro rG4-sensing assays validated rG4. Blue characters highlight rG4-forming sequences. rG4 formation was analyzed by using N-methyl mesoporphyrin IX (NMM), which senses rG4 by enhanced fluorescence (λex = 399 and λem = 610 nm). The error bars indicate means ± s.e.m.; the rG4-sensing assays were performed with three biological replicates, each with two technical replicates. Each “◇” indicates a data point. Source data are provided as a Source Data file.