(C) Add-back assay using the WT and mutant condensin I complexes. Xenopus extracts depleted of endogenous condensin complexes were supplemented with the purified complexes (from top to bottom; WT, IV-5Q, ∆G, ∆G[IV-5Q]). The supplemented extracts were then incubated with sperm nuclei to assemble mitotic chromosomes. The samples were fixed and labeled with an antibody against mSMC4 (red). DNA was counterstained with DAPI (blue). The data from a single representative experiment out of two repeats are shown. In the experiment shown here, multiple images were collected for condensin-depleted extracts supplemented with the WT (n = 17), IV-5Q (n = 22), ∆G (n = 20) and ∆G(IV-5Q) (n = 25) complexes. The scale bar represents 10 μm. 