Date of Award
8-20-2024
Degree Name
Doctor of Philosophy (PhD)
Degree Type
Dissertation
Abstract
Living cells inherently perceive and react to environmental stimuli, enabling communication within and between communities and across biological kingdoms. To harness the power of these natural genetic regulatory systems, synthetic biology has expanded its toolkit, facilitating applications in biosensing and metabolic engineering. However, natural sensory elements often face challenges in rapidly differentiating and accurately reporting chemicals with high structural resemblance, particularly in complex biomedical or environmental samples. In this work, we have enhanced the performance of existing genetic circuits to remove signal crosstalk, achieving exclusive responses to single effectors, and we have implemented modular sensory elements to expand detection ranges and host applicability. Initially, we engineered transcription factor-based biosensors for ligand-specific detection of aromatic amino acids and their derivatives through structure-guided design. Additionally, a plug-and-play strategy involving multiplexed enzyme modules supported the conversion of non-native substrates into detectable ligands by engineered transcription factors, significantly broadening the target scope in probiotic Escherichia coli. Finally, we developed novel RNA-based biosensors in Saccharomyces cerevisiae by integrating the ligand-sensing functions of aptamers and the RNA strand-sensing capabilities of toehold switches into CRISPR-guide RNAs. Collectively, this work lays the foundation for potential clinical and industrial applications of biosensors with enhanced orthogonality, modularity, and composability.
Language
English (en)
Chair
Yinjie Tang