Figure 4.

Smc4 Phosphorylation Regulates Condensin Dynamics and Chromosome Condensation

(A) Schematic representation of the gene loci expressing Smc4-Clb2 and Smc4-Clb2^ΔCdk fusion proteins.

(B) Fluorescence recovery half-times, following photobleaching, of the Brn1-3mNeonGreen signal in homozygous diploid SMC4-CLB2^ΔCDK and SMC4-CLB2 cells in interphase and metaphase. Error bars represent mean ± SD (n ≥ 31) (ordinary one-way ANOVA, Sidak’s multiple comparison test).

(C) Model of chromosome condensation driven by cell-cycle-regulated Smc4 phosphorylation, resulting in stabilization of condensin-DNA binding. This promotes chromosome compaction if the condensation reaction proceeds by either diffusion capture or loop extrusion.

See also Figure S6 for additional condensin dynamics, phosphorylation, and chromosome condensation assays.