Promoter Kinetics

Promoter Kinetics and Stochasticity of Gene Expression

Fast transitions between promoter states was one of the assumptions that had to be fufilled, according to (), in order for deterministic gene expression models to resemble experimental data. This is becuase if a promoter remains in an active state it allows many "short bursts" of mRNA synthesis; the same rate limiting steps that inhibit turnover time of promoter activation and repression also cause the promoter to stay in a repressed state for longer, while it produces very low amounts of mRNA. Diagrams of protein accumulation in genes with slow transition states are characterized by two bistable states that mirror the state of the promoter. This is contrasted with the steady-state concentration of proteins who are expressed by promoters with fast transition kinetics. While most biochemical processes in prokaryotes are assumed to have such a fast turnover rate of promoter state that the effect can be ignored, the kinetics of the expression of some genes are a source of a large amount of variability.