Fig. 3. Aurora B regulates centromeric enrichment of condensin I. (A) Mitotic HeLa cells were spread on glass slides under hypotonic conditions, fixed and stained with antibodies against condensin I (kleisin-). CREST autoimmune serum was used to detect centromeric regions. Inactivation of Aurora B kinase activity by Hesperadin treatment (100 nM) was monitored by staining for phosphorylated Histone H3 Serine 10 (H3S10ph). Chromosomes were counterstained with DAPI (1 µg/ml). Bar, 10 µm. (B) A magnified chromosome of the same experiment is shown stained with DAPI, antibodies against kleisin- and CREST autoimmune serum. Bar, 2 µm. (C) Quantification of condensin I (kleisin- and Cap-D2) and condensin II (Cap-D3) at centromeric regions was done using the CREST signal as a reference and to determine the location of centromeres during image segmentation. Mean ± s.d. from more than 100 different centromeres of at least ten different cells for each condition are shown. The presented graphs are normalised to the control value.