Semi-Synthetic Mammalian Gene Regulatory Networks

Abstract

While synthetic biology was until recently restricted to network assembly and testing in prokaryotes, decisive advances have been achieved in eukaryotic systems based on current availability of different human-compatible transgene control technologies. The majority of transgene control networks available to date are fully synthetic. Yet, in order to develop their full anticipated therapeutic potential, synthetic transgene control circuits need to be well interconnected with the host cell’s regulatory networks in order to enable physiologic control of prosthetic molecular expression units. We have designed three semi-synthetic transcription control networks able to integrate physiologic oxygen levels and artificial antibiotic signals to produce expression readout with NOT IF or NOR-type Boolean logic or discrete multilevel control of several intracellular and secreted model product proteins. Subtle differences in the regulation performance of the endogenous oxygensensing system in CHO-K1 and human HT-1080 switched the semi-synthetic network’s readout from a classic four-level (high, medium, low, basal) regulatory cascade to a network enabling six discrete transgene expression levels.