Special Bioengineering Seminar

Synthetic DNA constructs can be used to reprogram cells to sense, compute, record information and to produce chemicals, medicines and materials. However, the functions of these constructs can impact on their host cell, and conversely the host cell background can also impact on the efficiency of the construct function. To uncover how construct function impacts on a host, we used multiplex RNAseq with an in vivo assay to reveal the major transcriptional changes that occur in response to synthetic construct expression. Our systems analysis led us to identify native biosensors for unnatural expression in E. coli strains and exploit these to build a CRISPR/dCas9-based feedback regulation system that automatically adjusts expression to ensure robust growth in many varied conditions. In parallel, to investigate how host background impacts a construct, we assessed the performance of metabolic pathway-encoding constructs hosted in synthetic yeast strains that have chromosomes that can be rearranged on demand. In vivo deletion and inversion of chromosomal regions quickly enabled new synthetic yeast host cells to be generated with greatly-enhanced xylose utilization, and improved violacein and penicillin biosynthesis.