Fig. 3: Sequestering the target mRNAs into optoMCP-FUS condensates inhibits protein translation.

A Schematic diagram showing translation inhibition, monitored with tagBFP fluorescence, due to the mRNA sequestration into light-activated condensates. B During 12 h of blue light activation, tagBFP fluorescence levels were measured for individual U2OS cells with the tagBFP mRNA reporter (middle). The bold curves are averaged values. (right and left) Confocal images before and after light activation are shown. n = 32 (optoMCP-FUS) and 30 (optoFUS). Cells were activated with filtered DIA light. C Normalized tagBFP intensity of individual cells after 12 h of light activation. The fluorescence intensities are normalized with the initial values of individual cells prior to light activation. n = 43 (optoFUS), 117 (optoMCP-FUS), and 15 (anisomycin). Statistical significance was calculated using Student’s two-tailed t test. ****P < 0.0001. P = 4.71E-11 (optoFUS and optoMCP-FUS) and 5.38E-17 (optoFUS and anisomycin). Data are mean ± SD. D Schematic of the effect of the optoMCP-FUS expression level on the extent of translation inhibition. E Scatter plot for the integrated intensity of optoMCP-FUS condensates for individual cells with varying expression levels. F Normalized tagBFP intensity after 12 h of light activation as a function of optoMCP-FUS expression levels. n = 32 (0–100), 25 (100–200), 34 (200–300) and 12 cells (300–400). Data are mean ± SD. Scale bar, 10 μm (B). a.u., arbitrary units. Source data for panels B, C, E, and F are provided in the Source Data file.