A Synthetic Transcription Platform for Programmable Gene Expression in Mammalian Cells

Abstract Precise, scalable, and sustainable control of genetic and cellular activities in mammalian cells is key to developing precision therapeutics and smart biomanufacturing. We created a highly tunable, modular, versatile CRISPR-based synthetic transcription system for the programmable control of gene expression and cellular phenotypes in mammalian cells. Genetic circuits consisting of well-characterized libraries of guide RNAs, binding motifs of synthetic operators, transcriptional activators, and additional genetic regulatory elements expressed mammalian genes in a highly predictable and tunable manner. We demonstrated the programmable control of reporter genes episomally and chromosomally, with up to 25-fold more EF1α promoter activity, in multiple cell types. We used these circuits to program secretion of human monoclonal antibodies and to control T cell effector function marked by interferon-γ production. Antibody titers and interferon-γ concentrations were significantly correlated with synthetic promoter strengths, providing a platform for programming gene expression and cellular function for biological, biomanufacturing, and biomedical applications.