Forces Acting on Chromosomes
Forces Acting on Chromosomes
Attachment of Sister Chromatids
Chromosome Structure
Chromosome Structure
Anaphase A and B
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Updated: May 10, 2026

Associated Chromosome Trap for Identifying Long-range DNA Interactions
Published on: April 23, 2011
Tongli Zhang1, Raquel A Oliveira, Bernhard Schmierer
1Oxford Centre for Integrative Systems Biology, Department of Biochemistry, University of Oxford, Oxford, United Kingdom.
Chromosome bi-orientation is essential for accurate cell division. This process is error-prone, and cells use mechanisms to correct misaligned chromosomes. The study explores how cells might achieve bi-orientation from unattached kinetochores. Tension between sister kinetochores creates a bistable switch, but this mechanism alone does not explain the initial steps. The researchers propose four possible mechanisms to address this issue. They find that trial-and-error oscillation and stochastic bistable switches are effective in promoting bi-orientation. These mechanisms are supported by experimental data. The study does not claim these are the only possible solutions but highlights their potential for efficiency and robustness.
Area of Science:
Background:
Chromosome segregation during cell division requires accurate bi-orientation. This process is inherently error-prone. Existing mechanisms help correct misaligned chromosomes. Prior research has shown that tension between sister kinetochores influences attachment stability. However, the initial steps of bi-orientation remain unclear. No prior work had resolved how unattached kinetochores transition to bi-orientation. This gap motivated the investigation of possible dynamical scenarios. The study aims to identify mechanisms that could support both efficiency and robustness in bi-orientation.
Purpose Of The Study:
The goal is to explore how cells achieve chromosome bi-orientation. The study focuses on error-prone processes and correction mechanisms. It examines tension-mediated feedback between sister kinetochores. The researchers aim to understand how bi-orientation initiates from unattached kinetochores. Four possible mechanisms are proposed to address this challenge. The study evaluates the impact of each mechanism on bi-orientation. Experimental data supports the assessment of these scenarios. The purpose is to identify robust and efficient pathways for bi-orientation.
Main Methods:
The researchers analyzed several dynamical scenarios for bi-orientation. They first modeled tension-mediated feedback between sister kinetochores. This feedback was shown to create a bistable switch. The model distinguishes between low and high tension states. However, the model fails to explain initial attachment from unattached kinetochores. The team proposed four alternative mechanisms to address this issue. These include molecular noise, tension-independent attachment, trial-and-error oscillation, and stochastic bistable switches. The impact of each mechanism on bi-orientation was assessed using simulations and experimental data.
Main Results:
Tension-mediated feedback leads to a bistable switch between low and high tension. This mechanism supports robust distinction between attachment states. However, it does not explain how bi-orientation initiates from unattached kinetochores. The researchers evaluated four proposed mechanisms for this process. Molecular noise and tension-independent attachment were considered. Trial-and-error oscillation and stochastic bistable switches were also tested. The trial-and-error oscillation showed potential for efficient bi-orientation. The stochastic bistable switch also supported robust and efficient bi-orientation. Experimental data supported the effectiveness of these two mechanisms.
Conclusions:
The study concludes that trial-and-error oscillation and stochastic bistable switches are effective. These mechanisms support both efficiency and robustness in bi-orientation. The researchers propose that these mechanisms may explain how cells initiate bi-orientation. The findings are supported by experimental data. The study does not claim that these are the only possible mechanisms. Other proposed mechanisms were less effective in simulations. The conclusions are limited to the scenarios tested in the study. The authors suggest further investigation of these mechanisms in live cells.
The study proposes trial-and-error oscillation and stochastic bistable switches as core mechanisms.
Tension-mediated feedback creates a bistable switch between low and high tension states.
Tension-independent attachment allows kinetochores to bind before tension is established.
Molecular noise may help kinetochores escape from incorrect attachment states.
Trial-and-error oscillations test different configurations until bi-orientation is achieved.
The authors suggest these switches promote both efficient and robust bi-orientation.