Abstract
Centromere-specific nucleosomes are a central feature of the kinetochore complex during mitosis, in which microtubules exert pulling and pushing forces upon the centromere. CENP-A nucleosomes have been assumed to be structurally unique, thereby providing resilience under tension relative to their H3 canonical counterparts. Here, we directly test this hypothesis by subjecting CENP-A and H3 octameric nucleosomes, assembled on random or on centromeric DNA sequences, to varying amounts of applied force by using single-molecule magnetic tweezers. We monitor individual disassembly events of CENP-A and H3 nucleosomes. Regardless of the DNA sequence, the force-mediated disassembly experiments for CENP-A and H3 nucleosomes demonstrate similar rupture forces, life time residency and disassembly steps. From these experiments, we conclude that CENP-A does not, by itself, contribute unique structural features to the nucleosome that lead to a significant resistance against force-mediated disruption. The data present insights into the mechanistic basis for how CENP-A nucleosomes might contribute to the structural foundation of the centromere in vivo.
| Original language | English |
|---|---|
| Article number | e0165078. |
| Number of pages | 18 |
| Journal | PLoS ONE |
| Volume | 11 |
| Issue number | 11 |
| DOIs | |
| Publication status | Published - 2016 |
Keywords
- nucleosomes
- satellite DNA
- histones
- centromeres
- magnets
- repeated sequences
- DNA fragment ligation
- DNA-binding proteins
- OA-Fund TU Delft