[Thu. 8 Sep. 2016] Prof. Jaeyoung Sung/Stochastic chemical dynamics in living cells and its consequence for the control capacity of living cells over biological functions

“Stochastic chemical dynamics in living cells and

its consequence for the control capacity of living cells

over biological functions”

To understand how and how accurately living cells control their biological functions, it is essential to construct a rigorous mathematical description for chemical dynamics of intracellular networks interacting with complex and hidden cell environment, which has been a formidable task. In this talk we introduce a novel model and stochastic kinetics for intracellular networks interacting with hidden cell environment, employing a complete description of cell state dynamics and its coupling to the system network. For a general model of intracellular birth-death processes, we present a simple and exact equation that relates the cell-to-cell variation in the product number to stochastic dynamics of birth and death processes occurring in cell environment. On the basis of the latter result, we propose an efficient method for quantitative analysis of the cell-to-cell variation in the mRNA and protein levels, which are responsible for phenotypic variations. Taking the new approach, we could provide excellent quantitative explanations for the control capacity of living cells over gene expression levels for a variety of different experimental systems in a unified manner. Our analysis of mRNA counting statistics in Escherichia coli shows that the transcription of an active gene is a strongly non-Poisson process whose rate has an oscillatory time correlation function. It has an important consequence for the cellular control over the transcriptional noise.

Refs: Lim et al., Phys. Rev. X 5, 031014 (2015); Yang et al., Nat. Commun. 5, 4761 (2014)

Prof. Jaeyoung Sung
Department of Chemistry & CRI-Center for Chemical Dynamics in Living Cells, Chung-Ang University, Seoul, Korea