Figure 4. Accumulation of nuclear RNA in human cells expressing G₄C₂ repeat expansion.

a, Reduced accumulation of newly synthesized RNA in the cytoplasm of cells transfected with G₄C₂-58 (white arrows) (imaged at 60 min). Yellow arrows: untransfected cells. b, Quantification of cytoplasmic RNA intensity following metabolic labeling of newly synthesized RNA (0 min: n > 24, 30 min: n > 7, 60 min: n > 25). ** p < 0.01, *** p < 0.001 by One Way ANOVA, Tukey’s Post Hoc test. c, Total RNA intensity following labeling of newly synthesized RNA at time point 0 min. d, PolyA⁺ RNA was measured by FISH in transiently transfected HeLa cells. Scale bar: 50 μm. e, Quantification of cells containing polyA⁺ RNA puncta, n = 30 cells per condition. f, Total cellular RNA in 2-month old iPSCs-derived cortical neurons. Scale bar: 25 μm. g, Quantification of the cytoplasmic RNA ratio in patient cortical neurons vs. controls. Values are mean ± s.e.m., n > 15 cells per line, ** p < 0.01 by Student’s t test.