Fig. 2: CHD1 forms condensates through the C-terminal IDR.

a Droplet assay of CHD1–Venus proteins (1 µM) highlighting the crucial role of the C-terminal IDR in condensation. Scale bars, 20 µm. Condensates within the 1.125 × 10⁻² mm² area, obtained from three independently prepared dishes, were analyzed and visualized using violin plots with boxplots, illustrating the mean, median, interquartile range, and 10^th–90^th percentiles denoted by white circles, black bars, grey boxes, and thin black lines, respectively. The size of each condensate was plotted as a dot on the right and analyzed using unpaired two tailed Student’s t-test. b Confocal images of HeLa cells expressing exogenous CHD1–Venus, demonstrating that the C-terminus IDR is crucial for nuclear condensate formation (left). Fluorescence localization patterns were consistent across three independent experiments. Scale bars, 5 µm. Western blot analysis performed using the Wes system (ProteinSimple), with anti-Vinculin (VINC) as the loading control (right). The CHD1-Venus variants were expressed at comparable levels to each other, and all exhibit elevated expression compared to endogenous CHD1 (indicated by the arrow). Note that the CHD1 antibody targets a C-terminal epitope, meaning it does not detect the CHD1^∆C or CHD1^∆NC variants. c Schematic illustrating the strategy for CHD1^WT–Venus knock-in (KI) HeLa cell generation (left). Western blot analysis of CHD1 and Venus in CHD1^WT–Venus KI HeLa cells, with anti-HSP90 used as loading control (right). KI band was consistently observed in three independent Western blot experiments. d Confocal images of CHD1^WT–Venus KI HeLa cells. Arrows indicate small condensates, while arrowheads indicate large condensates ( > 1 µm in diameter). Small and large condensates are observed within the nucleoplasm and nucleolus, respectively. Scale bars, 5 µm. e Confocal images of Spot-FRAP analysis on CHD1^WT–Venus KI HeLa cells (left panel). Scale bar, 5 µm. FRAP signal in the bleached area before and after bleaching (right panel). Data are presented as the mean ± SEM, n = 3 independent experiments. Source data are provided as a Source Data file.