Team:BostonU/Abstract and Motivation
While natural systems integrate diverse “digital” signals to precisely specify “analog” gene expression levels, synthetic systems thus far have focused on controlling expression in either a digital or an analog capacity. Our team sought to develop a “digitized-analog” expression system using CRISPR-dCas9, capable of specifying varied exogenous gene expression levels based on different signals. We first developed digital elements by pairing gRNAs with minimal operator promoters and using dCas9 to transactivate. We then created analog elements by multimerizing operator sites to obtain graded activation levels. Finally, we integrated our digital and analog elements into higher-order genetic logic circuits to achieve varying expression responses. We characterized and optimized our system in human cells, enabling synthetic biologists to better control transgene expression for important therapeutic applications.
