FIG. 8.

Changes to the SMC complex-mediated loops during the cell cycle. (a) Logarithmic plot of the contact probability P_s vs genomic distance s for the Hi-C data for the I and M phases. P_s has distinct decaying patterns in the I ($\sim -1$) and M ($\sim -0.5$) phases within 10 Mb. (b) The slope of $P_s(s)\sim s^{\alpha (s)}$ has local maxima in the I and M phases, corresponding to the sizes of the cohesion and condensin loops, respectively. There are two peaks in the M phase profile. The more significant maximum is at ∼800 kb, which corresponds to the loop formed by condensin.²⁶ Condensin binding can also lead to enhanced contacts at short ranges (∼300 kb), similar to the range in which cohesin forms loops in the I phase.^26,74 (c) Time evolution of $\alpha (s)$ for the I → M transition. The dashed lines indicate the sizes of the cohesin (green) and condensin (blue) loops. (d) The change of $\alpha (s)$ for the cohesin and condensin loops extracted from (c) for the I → M transition. (e), (f) As (c) and (d) but for the M → I transition.