19 / 2024-09-08 20:08:28

Chromosome shortening in axis turbulence pattern

chromosome structure, sister chromatids, chromosome compaction, mechanical stress, chromosome axis turbulence

Chromosomes are organized in emissioned loops that are centralized by a chromosome axis, while sister chromatids are connected by evenly-spaced mini-axis bridges. These two features require chromosomes to adjust their length and profile as the cell cycle progresses, from a single axis to parallel two units. Our previous data suggest that chromosomes experience mechanical stress, but how the axis components (such as protein components) execute their function on the emergence of mechanical stress is still unclear. In this study, with new measurement tool and method we developed, we found they execute this function by forming a bulge turbulence on the axis. The bulge turbulence is dynamic during mitosis and reaches the highest dynamics at early anaphase. The axis turbulence, mediated by Topo II activity and inter-sister cohesin, may be responsible for the emergence of inner mechanical stress, which subsequently coordinates with inter-sister bridges to shepherd chromosome shortening and parallel sister chromatids.