At the heart of synthetic biology is the assembly of genetic components into “circuits” that perform desired operations in living cells, with the long-term goal of empowering these cells to solve critical problems in healthcare, energy, the environment and other domains, from cancer treatment to toxic waste cleanup. While much of this work is done using bacterial cells, new techniques are emerging to reprogram eukaryotic cells—those found in plants and animals, including humans—to perform such tasks.

To engineer useful genetic circuits in eukaryotic cells, synthetic biologists typically manipulate sequences of DNA in an organism’s genome, but Assistant Professor Ahmad “Mo” Khalil (BME), Professor James J. Collins (BME, MSE, SE) postdoctoral fellow Albert J. Keung (BME) and other researchers at Boston University’s Center of Synthetic Biology (CoSBi) have another idea that could vastly increase their capabilities. Rather than manipulate the DNA sequence directly, the CoSBi engineers are exploiting a class of proteins that regulate chromatin, the intricate structure of DNA and proteins that condenses and packages a genome to fit within the cell. These chromatin regulator (CR) proteins play a key role in expressing—turning on and off—genes throughout the cell, so altering their makeup could provide a new pathway for engineering the cell’s genetic circuits to perform desired functions.