Zhang, TongliOliveira, Raquel A.Schmierer, BernhardNovák, Béla2016-06-272016-06-272013-06-18Tongli Zhang, Raquel A. Oliveira, Bernhard Schmierer, Béla Novák, Dynamical Scenarios for Chromosome Bi-orientation, Biophysical Journal, Volume 104, Issue 12, 18 June 2013, Pages 2595-2606, ISSN 0006-3495, http://dx.doi.org/10.1016/j.bpj.2013.05.005. (http://www.sciencedirect.com/science/article/pii/S0006349513005298)http://hdl.handle.net/10400.7/666Chromosome bi-orientation at the metaphase spindle is essential for precise segregation of the genetic material. The process is error-prone, and error-correction mechanisms exist to switch misaligned chromosomes to the correct, bi-oriented configuration. Here, we analyze several possible dynamical scenarios to explore how cells might achieve correct bi-orientation in an efficient and robust manner. We first illustrate that tension-mediated feedback between the sister kinetochores can give rise to a bistable switch, which allows robust distinction between a loose attachment with low tension and a strong attachment with high tension. However, this mechanism has difficulties in explaining how bi-orientation is initiated starting from unattached kinetochores. We propose four possible mechanisms to overcome this problem (exploiting molecular noise; allowing an efficient attachment of kinetochores already in the absence of tension; a trial-and-error oscillation; and a stochastic bistable switch), and assess their impact on the bi-orientation process. Based on our results and supported by experimental data, we put forward a trial-and-error oscillation and a stochastic bistable switch as two elegant mechanisms with the potential to promote bi-orientation both efficiently and robustly.engAnimalsChromosome SegregationChromosomesHumansKinetochoresStochastic ProcessesChromosome PositioningModels, Geneticjournal article10.1016/j.bpj.2013.05.005