Abstract: Genetic circuits that control transgene expression in response to pre-defined transcriptional cues would enable the development of smart therapeutics. The present disclosure relates to engineered programmable single-transcript RNA sensors in which adenosine deaminases acting on RNA (ADARs) autocatalytically convert trigger hybridization into a translational output. This system amplifies the signal from editing by endogenous ADAR through a positive feedback loop. Amplification is mediated by the expression of a hyperactive, minimal ADAR variant and its recruitment to the edit site via an orthogonal RNA targeting mechanism. This topology confers high dynamic range, low background, minimal off-target effects, and a small genetic footprint. The circuits and systems disclosed herein leverage an ability to detect single nucleotide polymorphisms and modulate translation in response to endogenous transcript levels in mammalian cells.

Abstract: Disclosed is a technique for constructing optogenetic amplifier and inverter circuits utilizing transcriptional activator/repressor pairs, in which expression of the transcriptional activator or repressor, respectively, is controlled by light-controlled transcription factors. This system is demonstrated utilizing the quinic acid regulon system from Neurospora crassa, or Q System, a transcriptional activator/repressor system. This is also demonstrated utilizing the galactose regulon from Saccharomyces cerevisiae, or GAL System. Such optogenetic amplifier circuits enable multi-phase microbial fermentations, in which different light schedules are applied in each phase to dynamically control different metabolic pathways for the production of proteins, fuels or chemicals.

Abstract: Microbial consortia exert great influence over the physiology of humans, animals, plants, and ecosystems. However, difficulty in controlling their composition and population dynamics have limited their application in medicine, agriculture, biotechnology, and the environment. The approach disclosed herein provides an effective method to dynamically control population compositions in microbial consortia, which we demonstrate in the context of co-culture fermentations for chemical production. Co-culture fermentations can improve chemical production from complex biosynthetic pathways over monocultures by distributing enzymes across multiple strains, thereby reducing metabolic burden, overcoming endogenous regulatory mechanisms, or exploiting natural traits of different microbial species. However, stabilizing and optimizing microbial sub-populations for maximal chemical production remains a major obstacle in the field.

Abstract: Disclosed herein are optogenetic circuits for the bacterium Escherichia coli that induce gene expression in darkness and repress it under blue light. Applying them to metabolic engineering improves chemical production compared to chemically induced controls in light-controlled fermentations. More particularly, these circuits can be used to control protein production with light. The system and method use light as a suitable alternative to chemical induction for microbial production of chemicals and proteins.