Fig. 3: HomoFRET captures the physical properties of FUS-RNA heterotypic condensates.
a–c Single-droplet steady-state anisotropy plot (a), representative anisotropy images (scale bar 4, 3, 3, and 5 µm for 0, 25, 50, and 100 ng/µL polyU RNA, respectively) (b) and corresponding homoFRET efficiencies (c) of FUS droplets doped with 20% FUS-eGFP with varying RNA (n = 38, 43, 36, 33, and 6 droplets for 0, 25, 50, 75, and 100 ng/µL RNA from 3 independent experiments). d Representative anisotropy decay obtained within droplets yielded triexponential decay kinetics (in the absence of RNA) and biexponential decay kinetics (in the presence of 50 ng/µL RNA). Data for droplets without RNA (control) in Fig. 3a, c, d are the same as shown for 2 µM FUS-eGFP droplets in Fig. 2g, i, j and included here for comparison. e The amplitude of the ultrafast unresolved homoFRET component for 0 and 50 ng/µL polyU RNA droplets recovered from anisotropy decay analysis shown in (d) (n = 9 droplets from 3 independent experiments). See Supplementary Table 1 for recovered parameters. f Representative anisotropy images showing the core-shell packing heterogeneity of droplets formed at an RNA concentration of 75 ng/µL (scale bar 3 µm for the entire image and 0.6 µm for a single-droplet, core, and shell). g Estimated FRET efficiencies obtained from core and shell regions shown in (f) (n = 17 individual droplets from 3 independent experiments). Data shown in box-and-whiskers plots indicates the 25th to 75th percentile (box), median (line), mean (white square), and 10th to 90th percentile (whiskers). The difference was statistically significant as determined by a one-way ANOVA test (for *** p ≤ 0.001 compared to the respective control). Source data are provided as a Source Data file.
