Performance Characteristics for Sensors and Circuits Used to Program E. coli

Abstract

The behavior of E. coli can be reprogrammed by the introduction of foreign segments of DNA. Three classes of genetic parts, termed sensors, circuits and actuators comprise the DNA programs. Sensors are gene products which allow the cell to detect physical or chemical information in its environment. Genetic engineers can use sensors directly from nature, modify them in some manner, or design them de novo to control cellular processes with extracellular or intracellular signals. Genetic circuits act to process information from sensors in order to dictate the behavior of the cell. They can be designed with combinations of “off the shelf” regulatory parts such as transcription factors and promoters, or in some cases can be used “as is” from nature. Finally, genetic circuits govern the expression of actuators, genes whose products perform some physical function to alter the state or the environment within which the cell exists. Using recent DNA synthesis and assembly technologies, genetic sensors, circuits and actuators can be combined to create programs that command cells to perform a series of tasks. This approach will transform the way that genetic engineers approach problems in biotechnology. This review covers the construction of genetic sensors and circuits for use in E. coli, as well as genetic methods to perturb their performance features.