Fig. 4: DNA strand passage by topo IIα is essential for protease-resistant lump formation.

a Frequency of lumps and loops on U-shape DNA formed by condensin I (cond I) and either topo IIα^WT (WT) or topo IIα^Y803F (YF). Percentages of DNAs per condition are plotted (red: lump, blue: loop, white: N.D., mean ± SEM). b Time trace of the size of a lump formed by condensin I in the presence of either topo IIα^WT or topo IIα^Y803F. The line and shaded area denote the Exponential fits and interquartile ranges (black: condensin I and topo IIα^WT, blue: condensin I and topo IIα^Y803F). Time 0 indicates the moment when condensin I bound to DNA. Data were collected from 3 trials. c Stability of lump in the presence of condensin I and either topo IIα^WT or topo IIα^Y803F. The translucent and solid points denote the individual lump and median of each trial, respectively. The bar represents the mean of the median ± SEM. d Size of lump formed in the presence of condensin I and either topo IIα^WT or topo IIα^Y803F. The bars denote the median and quartiles. e Rate of lump formation in the presence of condensin I and either topo IIα^WT or topo IIα^Y803F. The bars denote the median and quartiles. f Frequency of protease-resistant and -sensitive lump in the presence of condensin I and either topo IIα^WT or topo IIα^Y803F. Percentages of lumps per condition are plotted (black: protease-resistant, light gray: protease-sensitive, mean ± SEM). g Changes in protease-resistant lumps after the 2nd topo IIα treatment were categorized into 4 groups and the percentages are plotted (white: increased or no change, light gray: decreased by no step, dark gray: decreased by one step, black: disappeared by one step, mean ± SEM). In all experiments in this figure, DNA was stained with SYTOX Orange. All data in this figure were collected from 3 trials. All pvalues are calculated by a two-tailed Mann–Whitney U test. Source data are provided as a Source Data file. Sample sizes are stated in the Source Data file.