Active Degradation Allows for Increased Information Transmission Rate in Genetic Control

In genetic regulation, time scale matters. Many organisms exist in changing, uncertain environments in which they are required to respond quickly to stress. They must do this without compromising the fidelity of the response. In this research, we use the multiple antibiotic resistance activator MarA from Escherichia coli as a case study in how active degradation of a master regulator balances tradeoffs in information transmission clarity and response rates. We use a combination of experimental, analytical and computation methods to consider how well a signal from MarA propagates to downstream genes and how effectively MarA coordinates the response between these downstream genes. If time scale is not important, a slowly changing regulator maximizes the information transmission and downstream coordination. However, over shorter time-scales, a quickly changing actively degraded regulator is ideal. This research demonstrates the utility of active degradation in genetic regulation and how it is essential to consider the time-scales of the stress to which the regulatory elements are adapted.