Modeling transcription dynamics in stochastic gene expression

Messenger RNA (mRNA) copy number fluctuations, typically characterized by plots of a scaled variance versus mean copy number, exhibit similar features for bacterial and mammalian cells. The frequently used two-state model can reproduce such features but cannot account for dynamics in the mRNA production rate. Recent measurements track mRNA production rate over the cell doubling cycle. I will discuss our attempts to reproduce features of mRNA copy number statistics using a ‘doubly stochastic’ model that accounts for dynamics in the mRNA production rate. I will conclude with comments on the apparent universality of mRNA statistics across bacterial and mammalian species.