The mean and noise of protein numbers in stochastic gene expression.

Gene expression is the central process in cells, and is stochastic in nature. In this work, we study the mean expression level of, and the expression noise in, a population of isogenic cells, assuming that transcription is activated by two sequential exponential processes of rates κ and λ. We find that the mean expression level often displays oscillatory dynamics, whereas most other models suggest that it always grows monotonically.