Fluctuating-rate model and stochastic phenotype transition of a single cell
主 题: Fluctuating-rate model and stochastic phenotype transition of a single cell
报告人: 葛颢 (北京国际数学研究中心和北京大学生物动态光学成像中心研究员)
时 间: 2015-04-26 14:45 - 15:30
地 点: 北京大学镜春园82号甲乙丙楼二层报告厅
We proposed a fluctuating-rate model for the stochastic biochemical dynamics in a single cell, which is indeed stochastic coupled Ordinary Differential Equations. We also found that the fluctuating-rate model yields a nonequilibrium landscape function, which, similar to the energy function for equilibrium fluctuation,provides the leading orders of fluctuations around each phenotypic state, as well as the transition ratesbetween the two phenotypic states. The rigorous proof needs to integrate the well-known Donsker-Varadhan theory and Feidlin-Wentzell theory in such an averaging case. We further apply this model to Lac operon, and show that the stochastic gene-state switching can significantly broaden the environmental parameter ranges for the existence of bistability induced by positive feedback, which can be beneficial dealing with unpredictable environmental changes. We also demonstrate that the transition rates between different phenotypic states achieve the maximal value at the intermediate region of gene-state switching, and the barrier term in the rate formula can help to distinguish two categories of bistability.
