Fig. 1: PICH can bind to exposed dsDNA on nucleosome-array constructs under tension.

a Representative fluorescence images and schematic representations of a nucleosome-array construct with Anti-H3-Alexa647 antibody labelled histones, tethered between two optically-trapped beads, after 1-minute incubation with PICH-eGFP and ATP (at 10 pN). The Anti-H3-Alexa647 and PICH-eGFP signals and a composite of the two are displayed in (i), (ii) and (iii), respectively. The dashed white boxes highlight the region containing the nucleosome-array construct. Scale bars correspond to 2 µm. Similar PICH and histone distributions were observed on >10 independent nucleosome-array constructs. b Top: Schematic representations of PICH binding to a nucleosome array at ~1 pN (i) and at ~3 pN (ii). The DNA, histone octamers and PICH are depicted in black, red and green, respectively. Middle: Representative kymographs (see Methods) and corresponding intensity profiles of PICH (green) and histones (red) after incubation of the construct with PICH-eGFP and ATP, at a tension of ~1 pN (i) and ~3 pN (ii). Note that in (i) and (ii) the histones were labelled with Anti-H3-Alexa647 and Atto-647N, respectively. The width of the kymographs corresponds to 2.9 µm. Bottom: Mean intensity profiles of PICH-eGFP visualized from the center of the DNA construct to each end at a tension of ~1 pN (i) and ~3 pN (ii). The dashed red lines indicate the area of nucleosome positioning sequences. N = 28/14 and 32/16 (measurements/constructs) for ~1 pN and ~3 pN, respectively. Gray areas reflect +SEM. Source data are provided as a Source Data File.