Extended Data Fig. 7 |. The CHM1 chromosome 13 centromere likely has one kinetochore site, while the CHM1 chromosome 19 centromere has two kinetochore sites.

a-d) Immuno-FISH staining of stretched metaphase chromosome spreads from CHM1 cells with a fluorescent antibody against CENP-C (an inner-kinetochore protein; green) as well as a fluorescent chromosome 13/21 α-satellite DNA probe (a,b; red) or a fluorescent chromosome 5/19 α-satellite DNA probe (c,d; red). We find that there is a single CENP-C signal that coincides with the chromosome 13/21 α-satellite probe for each chromosome 13 sister chromatid, indicating that this chromosome likely has one kinetochore (a,b). Conversely, we find that there are two CENP-C signals that coincide with a single chromosome 5/19 α-satellite probe signal for each sister chromatid, indicating there are likely two kinetochores on this chromosome (c,d). Each experiment was performed three times with similar results. n = 32 and 34 metaphase chromosome spreads were analysed for chromosomes 13 and 19, respectively. Insets are magnified 1.7-fold (panels a and c) or 3.9-fold (panels b and d). Bar, 10 μm.