Semi-Synthetic Mammalian Gene Regulatory Networks

Abstract

While synthetic biology was until recently restricted to networkassembly and testing in prokaryotes, decisive advances have beenachieved in eukaryotic systems based on current availability ofdifferent human-compatible transgene control technologies. The majorityof 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 withthe host cell's regulatory networks in order to enable physiologiccontrol of prosthetic molecular expression units. We have designed threesemi-synthetic transcription control networks able to integratephysiologic oxygen levels and artificial antibiotic signals to produceexpression readout with NOT IF or NOR-type Boolean logic or discretemulti-level control of several intracellular and secreted model productproteins. Subtle differences in the regulation performance of theendogenous oxygen-sensing system in CHO-K1 and human HT-1080 switchedthe semi-synthetic network's readout from a classic four-level (high,medium, low, basal) regulatory cascade to a network enabling sixdiscrete transgene expression levels.