Frequency spectrum of chemical fluctuation A probe of reaction mechanism and dynamics

摘要

Recent advances in single-cell experimental techniques enable direct visualization of dynamic fluctuations of the biomolecular concentration in each cell; however, a robust, quantitative understanding of the stochastic dynamics of the chemical noise in living cells has yet to be achieved. To understand how the frequency spectrum of product number fluctuation is related to the topology of the reaction network and the dynamics of elementary processes composing the network, we derived an exact analytic result for the frequency spectrum of the product number fluctuation starting from a generalized master equation, enabling the extraction of the frequency spectrum of the reaction rate fluctuation (FSRR) from the frequency spectrum of the product number fluctuation (FSPN). The FSRR serves as a sensitive probe of the mechanism and dynamics of the product creation process; the FSRR vanishes when product creation is a Poisson process. We demonstrated our approach to frequency spectrum analysis of chemical fluctuation for generalized enzyme kinetic models, the gene network model of luciferase expression under the Bmal 1a promoter in mouse fibroblast cells, and a more general vibrant gene network model.