Curated Optogenetic Publication Database

Search precisely and efficiently by using the advantage of the hand-assigned publication tags that allow you to search for papers involving a specific trait, e.g. a particular optogenetic switch or a host organism.

Qr: host:"E. coli"
Showing 51 - 75 of 153 results
51.

A biological camera that captures and stores images directly into DNA.

blue red PhyB/PIF3 VVD E. coli Nucleic acid editing Multichromatic
Nat Commun, 3 Jul 2023 DOI: 10.1038/s41467-023-38876-w Link to full text
Abstract: The increasing integration between biological and digital interfaces has led to heightened interest in utilizing biological materials to store digital data, with the most promising one involving the storage of data within defined sequences of DNA that are created by de novo DNA synthesis. However, there is a lack of methods that can obviate the need for de novo DNA synthesis, which tends to be costly and inefficient. Here, in this work, we detail a method of capturing 2-dimensional light patterns into DNA, by utilizing optogenetic circuits to record light exposure into DNA, encoding spatial locations with barcoding, and retrieving stored images via high-throughput next-generation sequencing. We demonstrate the encoding of multiple images into DNA, totaling 1152 bits, selective image retrieval, as well as robustness to drying, heat and UV. We also demonstrate successful multiplexing using multiple wavelengths of light, capturing 2 different images simultaneously using red and blue light. This work thus establishes a 'living digital camera', paving the way towards integrating biological systems with digital devices.
52.

Detecting Photoactivatable Cre-mediated Gene Deletion Efficiency in Escherichia coli.

blue Magnets E. coli Transgene expression
Bio Protoc, 5 Jun 2023 DOI: 10.21769/bioprotoc.4685 Link to full text
Abstract: Gene deletion is one of the standard approaches in genetics to investigate the roles and functions of target genes. However, the influence of gene deletion on cellular phenotypes is usually analyzed sometime after the gene deletion was introduced. Such lags from gene deletion to phenotype evaluation could select only the fittest fraction of gene-deleted cells and hinder the detection of potentially diverse phenotypic consequences. Therefore, dynamic aspects of gene deletion, such as real-time propagation and compensation of deletion effects on cellular phenotypes, still need to be explored. To resolve this issue, we have recently introduced a new method that combines a photoactivatable Cre recombination system and microfluidic single-cell observation. This method enables us to induce gene deletion at desired timings in single bacterial cells and to monitor their dynamics for prolonged periods. Here, we detail the protocol for estimating the fractions of gene-deleted cells based on a batch-culture assay. The duration of blue light exposure significantly affects the fractions of gene-deleted cells. Therefore, gene-deleted and non-deleted cells can coexist in a cellular population by adjusting the duration of blue light exposure. Single-cell observations under such illumination conditions allow the comparison of temporal dynamics between gene-deleted and non-deleted cells and unravel phenotypic dynamics provoked by gene deletion.
53.

OptoCRISPRi-HD: Engineering a Bacterial Green-Light-Activated CRISPRi System with a High Dynamic Range.

green CcaS/CcaR E. coli Control of cytoskeleton / cell motility / cell shape Transgene expression
ACS Synth Biol, 22 May 2023 DOI: 10.1021/acssynbio.3c00035 Link to full text
Abstract: The ability to modulate gene expression is crucial for studying gene function and programming cell behaviors. Combining the reliability of CRISPRi and the precision of optogenetics, the optoCRISPRi technique is emerging as an advanced tool for live-cell gene regulation. Since previous versions of optoCRISPRi often exhibit no more than a 10-fold dynamic range due to the leakage activity, they are not suitable for targets that are sensitive to such leakage or critical for cell growth. Here, we describe a green-light-activated CRISPRi system with a high dynamic range (40 fold) and the flexibility of changing targets in Escherichia coli. Our optoCRISPRi-HD system can efficiently repress essential genes, nonessential genes, or inhibit the initiation of DNA replication. Providing a regulative system with high resolution over space-time and extensive targets, our study would facilitate further research involving complex gene networks, metabolic flux redirection, or bioprinting.
54.

Engineered allostery in light-regulated LOV-Turbo enables precise spatiotemporal control of proximity labeling in living cells.

blue AsLOV2 iLID E. coli HEK293T mouse in vivo rat cortical neurons S. cerevisiae Transgene expression
Nat Methods, 15 May 2023 DOI: 10.1038/s41592-023-01880-5 Link to full text
Abstract: The incorporation of light-responsive domains into engineered proteins has enabled control of protein localization, interactions and function with light. We integrated optogenetic control into proximity labeling, a cornerstone technique for high-resolution proteomic mapping of organelles and interactomes in living cells. Through structure-guided screening and directed evolution, we installed the light-sensitive LOV domain into the proximity labeling enzyme TurboID to rapidly and reversibly control its labeling activity with low-power blue light. 'LOV-Turbo' works in multiple contexts and dramatically reduces background in biotin-rich environments such as neurons. We used LOV-Turbo for pulse-chase labeling to discover proteins that traffic between endoplasmic reticulum, nuclear and mitochondrial compartments under cellular stress. We also showed that instead of external light, LOV-Turbo can be activated by bioluminescence resonance energy transfer from luciferase, enabling interaction-dependent proximity labeling. Overall, LOV-Turbo increases the spatial and temporal precision of proximity labeling, expanding the scope of experimental questions that can be addressed with proximity labeling.
55.

An Adenosylcobalamin Specific Whole-Cell Biosensor.

green TtCBD E. coli Control of cell-cell / cell-material interactions
Adv Healthc Mater, 1 May 2023 DOI: 10.1002/adhm.202300835 Link to full text
Abstract: Vitamin B12 (cobalamin) is essential for human health and its deficiency results in anemia and neurological damage. Vitamin B12 exists in different forms with various bioactivity but most sensors are unable to discriminate between them. Here, a whole-cell agglutination assay that is specific for adenosylcobalamin (AboB12), which is one of two bioactive forms, is reported. This biosensor consists of Escherichia coli that express the AdoB12 specific binding domain of CarH at their surface. In the presence of AdoB12, CarH forms tetramers, which leads to specific bacterial cell-cell adhesions and agglutination. These CarH tetramers disassemble upon green light illumination such that reversion of the bacterial aggregation can serve as internal quality control. The agglutination assay has a detection limit of 500 nм AdoB12, works in protein-poor biofluids such as urine, and has high specificity to AdoB12 over other forms of vitamin B12 as also demonstrated with commercially available supplements. This work is a proof of concept for a cheap and easy-to-readout AdoB12 sensor that can be implemented at the point-of-care to monitor high-dose vitamin B12 supplementation.
56.

Light inducible protein degradation in E. coli with LOVtag.

blue AsLOV2 EL222 E. coli
bioRxiv, 26 Feb 2023 DOI: 10.1101/2023.02.25.530042 Link to full text
Abstract: Molecular tools for optogenetic control allow for spatial and temporal regulation of cell behavior. In particular, light controlled protein degradation is a valuable mechanism of regulation because it can be highly modular, used in tandem with other control mechanisms, and maintain functionality throughout growth phases. Here, we engineered LOVtag, a protein tag that can be appended to a protein of interest for inducible degradation in Escherichia coli using blue light. We demonstrate the modularity of LOVtag by using it to tag a range of proteins, including the LacI repressor, CRISPRa activator, and the AcrB efflux pump. Additionally, we demonstrate the utility of pairing the LOVtag with existing optogenetic tools to enhance performance by developing a combined EL222 and LOVtag system. Finally, we use the LOVtag in a metabolic engineering application to demonstrate post-translational control of metabolism. Together, our results highlight the modularity and functionality of the LOVtag system, and introduce a powerful new tool for bacterial optogenetics.
57.

An optogenetic toolkit for light-inducible antibiotic resistance.

blue VVD E. coli Transgene expression Nucleic acid editing
Nat Commun, 23 Feb 2023 DOI: 10.1038/s41467-023-36670-2 Link to full text
Abstract: Antibiotics are a key control mechanism for synthetic biology and microbiology. Resistance genes are used to select desired cells and regulate bacterial populations, however their use to-date has been largely static. Precise spatiotemporal control of antibiotic resistance could enable a wide variety of applications that require dynamic control of susceptibility and survival. Here, we use light-inducible Cre recombinase to activate expression of drug resistance genes in Escherichia coli. We demonstrate light-activated resistance to four antibiotics: carbenicillin, kanamycin, chloramphenicol, and tetracycline. Cells exposed to blue light survive in the presence of lethal antibiotic concentrations, while those kept in the dark do not. To optimize resistance induction, we vary promoter, ribosome binding site, and enzyme variant strength using chromosome and plasmid-based constructs. We then link inducible resistance to expression of a heterologous fatty acid enzyme to increase production of octanoic acid. These optogenetic resistance tools pave the way for spatiotemporal control of cell survival.
58.

A red light-controlled probiotic bio-system for in-situ gut-brain axis regulation.

red Cph1 E. coli Transgene expression Cell death
Biomaterials, 20 Jan 2023 DOI: 10.1016/j.biomaterials.2023.122005 Link to full text
Abstract: Microbes regulate brain function through the gut-brain axis, deriving the technology to modulate the gut-brain axis in situ by engineered probiotics. Optogenetics offers precise and flexible strategies for controlling the functions of probiotics in situ. However, the poor penetration of most frequently used short wavelength light has limited the application of optogenetic probiotics in the gut. Herein, a red-light optogenetic gut probiotic was applied for drug production and delivery and regulation of the host behaviors. Firstly, a Red-light Optogenetic E. coli Nissle 1917 strain (ROEN) that could respond to red light and release drug product by light-controlled lysis was constructed. The remaining optical power of red light after 3 cm tissue was still able to initiate gene expression of ROEN and produce about approximately 3-fold induction efficiency. To give full play to the in vivo potential of ROEN, its responsive ability of the penetrated red light was tested, and its encapsulation was realized by PH-sensitive alginate microcapsules for further oral administration. The function of ROEN for gut-brain regulation was realized by releasing Exendin-4 fused with anti-neonatal Fc receptor affibody. Neuroprotection and behavioral regulation effects were evaluated in the Parkinson's disease mouse model, after orally administration of ROEN delivering Exendin-4 under optogenetic control in the murine gut. The red-light optogenetic probiotic might be a perspective platform for in situ drug delivery and gut-brain axis regulation.
59.

Near-Infrared Nano-Optogenetic Activation of Cancer Immunotherapy via Engineered Bacteria.

blue EL222 E. coli Signaling cascade control Transgene expression
Adv Mater, 31 Oct 2022 DOI: 10.1002/adma.202207198 Link to full text
Abstract: Certain anaerobic microbes with the capability to colonize in tumor microenvironment tend to express the heterologous gene in a sustainable manner, which would inevitably comprise the therapeutic efficacy and induce off-tumor toxicity in vivo. To improve the therapeutic precision and controllability of bacteria-based therapeutics, Escherichia coli Nissle 1917 (EcN) engineered to sense blue light and release the encoded flagellin B (flaB), is conjugated with lanthanide upconversion nanoparticles (UCNPs) for near-infrared (NIR) nano-optogenetic cancer immunotherapy. Upon 808 nm photoirradiation, UCNPs emit at the blue region to photoactivate the EcN for secretion of flaB, which subsequently binds to Toll-like receptor 5 expressed on the membrane of macrophages for activating immune response via MyD88-dependent signal pathway. Such synergism leads to significant tumor regression in different tumor models and metastatic tumors with negligible side effects. Our studies based on NIR nano-optogenetic platform highlight the rational of leveraging the optogenetic tools combined natural propensity of certain bacteria for cancer immunotherapy. This article is protected by copyright. All rights reserved.
60.

Upconversion Optogenetic Engineered Bacteria System for Time-Resolved Imaging Diagnosis and Light-Controlled Cancer Therapy.

blue YtvA E. coli Transgene expression Cell death
ACS Appl Mater Interfaces, 6 Oct 2022 DOI: 10.1021/acsami.2c14633 Link to full text
Abstract: Engineering bacteria can achieve targeted and controllable cancer therapy using synthetic biology technology and the characteristics of tumor microenvironment. Besides, the accurate tumor diagnosis and visualization of the treatment process are also vital for bacterial therapy. In this paper, a light control engineered bacteria system based on upconversion nanoparticles (UCNP)-mediated time-resolved imaging (TRI) was constructed for colorectal cancer theranostic and therapy. UCNP with different luminous lifetimes were separately modified with the tumor targeting molecule (folic acid) or anaerobic bacteria (Nissle 1917, EcN) to realize the co-localization of tumor tissues, thus improving the diagnostic accuracy based on TRI. In addition, blue light was used to induce engineered bacteria (EcN-pDawn-φx174E/TRAIL) lysis and the release of tumor apoptosis-related inducing ligand (TRAIL), thus triggering tumor cell death. In vitro and in vivo results indicated that this system could achieve accurate tumor diagnosis and light-controlled cancer therapy. EcN-pDawn-φx174E/TRAIL with blue light irradiation could inhibit 53% of tumor growth in comparison to that without blue light irradiation (11.8%). We expect that this engineered bacteria system provides a new technology for intelligent bacterial therapy and the construction of cancer theranostics.
61.

Blue Light Signaling Regulates Escherichia coli W1688 Biofilm Formation and l-Threonine Production.

blue Magnets E. coli Control of cell-cell / cell-material interactions
Microbiol Spectr, 27 Sep 2022 DOI: 10.1128/spectrum.02460-22 Link to full text
Abstract: Escherichia coli biofilm may form naturally on biotic and abiotic surfaces; this represents a promising approach for efficient biochemical production in industrial fermentation. Recently, industrial exploitation of the advantages of optogenetics, such as simple operation, high spatiotemporal control, and programmability, for regulation of biofilm formation has garnered considerable attention. In this study, we used the blue light signaling-induced optogenetic system Magnet in an E. coli biofilm-based immobilized fermentation system to produce l-threonine in sufficient quantity. Blue light signaling significantly affected the phenotype of E. coli W1688. A series of biofilm-related experiments confirmed the inhibitory effect of blue light signaling on E. coli W1688 biofilm. Subsequently, a strain lacking a blue light-sensing protein (YcgF) was constructed via genetic engineering, which substantially reduced the inhibitory effect of blue light signaling on biofilm. A high-efficiency biofilm-forming system, Magnet, was constructed, which enhanced bacterial aggregation and biofilm formation. Furthermore, l-threonine production was increased from 10.12 to 16.57 g/L during immobilized fermentation, and the fermentation period was shortened by 6 h. IMPORTANCE We confirmed the mechanism underlying the inhibitory effects of blue light signaling on E. coli biofilm formation and constructed a strain lacking a blue light-sensing protein; this mitigated the aforementioned effects of blue light signaling and ensured normal fermentation performance. Furthermore, this study elucidated that the blue light signaling-induced optogenetic system Magnet effectively regulates E. coli biofilm formation and contributes to l-threonine production. This study not only enriches the mechanism of blue light signaling to regulate E. coli biofilm formation but also provides a theoretical basis and feasibility reference for the application of optogenetics technology in biofilm-based immobilized fermentation systems.
62.

Light-Dependent Control of Bacterial Expression at the mRNA Level.

blue PAL YtvA E. coli Transgene expression
ACS Synth Biol, 21 Sep 2022 DOI: 10.1021/acssynbio.2c00365 Link to full text
Abstract: Sensory photoreceptors mediate numerous light-dependent adaptations across organisms. In optogenetics, photoreceptors achieve the reversible, non-invasive, and spatiotemporally precise control by light of gene expression and other cellular processes. The light-oxygen-voltage receptor PAL binds to small RNA aptamers with sequence specificity upon blue-light illumination. By embedding the responsive aptamer in the ribosome-binding sequence of genes of interest, their expression can be downregulated by light. We developed the pCrepusculo and pAurora optogenetic systems that are based on PAL and allow to down- and upregulate, respectively, bacterial gene expression using blue light. Both systems are realized as compact, single plasmids that exhibit stringent blue-light responses with low basal activity and up to several 10-fold dynamic range. As PAL exerts light-dependent control at the RNA level, it can be combined with other optogenetic circuits that control transcription initiation. By integrating regulatory mechanisms operating at the DNA and mRNA levels, optogenetic circuits with emergent properties can thus be devised. As a case in point, the pEnumbra setup permits to upregulate gene expression under moderate blue light whereas strong blue light shuts off expression again. Beyond providing novel signal-responsive expression systems for diverse applications in biotechnology and synthetic biology, our work also illustrates how the light-dependent PAL-aptamer interaction can be harnessed for the control and interrogation of RNA-based processes.
63.

Optogenetic Control of Bacterial Expression by Red Light.

blue red DrBphP PAL E. coli Transgene expression
ACS Synth Biol, 23 Aug 2022 DOI: 10.1021/acssynbio.2c00259 Link to full text
Abstract: In optogenetics, as in nature, sensory photoreceptors serve to control cellular processes by light. Bacteriophytochrome (BphP) photoreceptors sense red and far-red light via a biliverdin chromophore and, in response, cycle between the spectroscopically, structurally, and functionally distinct Pr and Pfr states. BphPs commonly belong to two-component systems that control the phosphorylation of cognate response regulators and downstream gene expression through histidine kinase modules. We recently demonstrated that the paradigm BphP from Deinococcus radiodurans exclusively acts as a phosphatase but that its photosensory module can control the histidine kinase activity of homologous receptors. Here, we apply this insight to reprogram two widely used setups for bacterial gene expression from blue-light to red-light control. The resultant pREDusk and pREDawn systems allow gene expression to be regulated down and up, respectively, uniformly under red light by 100-fold or more. Both setups are realized as portable, single plasmids that encode all necessary components including the biliverdin-producing machinery. The triggering by red light affords high spatial resolution down to the single-cell level. As pREDusk and pREDawn respond sensitively to red light, they support multiplexing with optogenetic systems sensitive to other light colors. Owing to the superior tissue penetration of red light, the pREDawn system can be triggered at therapeutically safe light intensities through material layers, replicating the optical properties of the skin and skull. Given these advantages, pREDusk and pREDawn enable red-light-regulated expression for diverse use cases in bacteria.
64.

Dynamic cybergenetic control of bacterial co-culture composition via optogenetic feedback.

blue Magnets E. coli Transgene expression
Nat Commun, 16 Aug 2022 DOI: 10.1038/s41467-022-32392-z Link to full text
Abstract: Communities of microbes play important roles in natural environments and hold great potential for deploying division-of-labor strategies in synthetic biology and bioproduction. However, the difficulty of controlling the composition of microbial consortia over time hinders their optimal use in many applications. Here, we present a fully automated, high-throughput platform that combines real-time measurements and computer-controlled optogenetic modulation of bacterial growth to implement precise and robust compositional control of a two-strain E. coli community. In addition, we develop a general framework for dynamic modeling of synthetic genetic circuits in the physiological context of E. coli and use a host-aware model to determine the optimal control parameters of our closed-loop compositional control system. Our platform succeeds in stabilizing the strain ratio of multiple parallel co-cultures at arbitrary levels and in changing these targets over time, opening the door for the implementation of dynamic compositional programs in synthetic bacterial communities.
65.

Computational framework for single-cell spatiotemporal dynamics of optogenetic membrane recruitment.

blue BcLOV4 E. coli
Cell Rep Methods, 6 Jul 2022 DOI: 10.1016/j.crmeth.2022.100245 Link to full text
Abstract: We describe a modular computational framework for analyzing cell-wide spatiotemporal signaling dynamics in single-cell microscopy experiments that accounts for the experiment-specific geometric and diffractive complexities that arise from heterogeneous cell morphologies and optical instrumentation. Inputs are unique cell geometries and protein concentrations derived from confocal stacks and spatiotemporally varying environmental stimuli. After simulating the system with a model of choice, the output is convolved with the microscope point-spread function for direct comparison with the observable image. We experimentally validate this approach in single cells with BcLOV4, an optogenetic membrane recruitment system for versatile control over cell signaling, using a three-dimensional non-linear finite element model with all parameters experimentally derived. The simulations recapitulate observed subcellular and cell-to-cell variability in BcLOV4 signaling, allowing for inter-experimental differences of cellular and instrumentation origins to be elucidated and resolved for improved interpretive robustness. This single-cell approach will enhance optogenetics and spatiotemporally resolved signaling studies.
66.

Hydrogel microcapsules containing engineered bacteria for sustained production and release of protein drugs.

blue EL222 E. coli Transgene expression Cell death
Biomaterials, 5 Jun 2022 DOI: 10.1016/j.biomaterials.2022.121619 Link to full text
Abstract: Subcutaneous administration of sustained-release formulations is a common strategy for protein drugs, which avoids first pass effect and has high bioavailability. However, conventional sustained-release strategies can only load a limited amount of drug, leading to insufficient durability. Herein, we developed microcapsules based on engineered bacteria for sustained release of protein drugs. Engineered bacteria were carried in microcapsules for subcutaneous administration, with a production-lysis circuit for sustained protein production and release. Administrated in diabetic rats, engineered bacteria microcapsules was observed to smoothly release Exendin-4 for 2 weeks and reduce blood glucose. In another example, by releasing subunit vaccines with bacterial microcomponents as vehicles, engineered bacterial microcapsules activated specific immunity in mice and achieved tumor prevention. The engineered bacteria microcapsules have potential to durably release protein drugs and show versatility on the size of drugs. It might be a promising design strategy for long-acting in situ drug factory.
67.

Regulating Bacterial Behavior within Hydrogels of Tunable Viscoelasticity.

blue YtvA E. coli Transgene expression
Adv Sci (Weinh), 11 Apr 2022 DOI: 10.1002/advs.202106026 Link to full text
Abstract: Engineered living materials (ELMs) are a new class of materials in which living organism incorporated into diffusive matrices uptake a fundamental role in material's composition and function. Understanding how the spatial confinement in 3D can regulate the behavior of the embedded cells is crucial to design and predict ELM's function, minimize their environmental impact and facilitate their translation into applied materials. This study investigates the growth and metabolic activity of bacteria within an associative hydrogel network (Pluronic-based) with mechanical properties that can be tuned by introducing a variable degree of acrylate crosslinks. Individual bacteria distributed in the hydrogel matrix at low density form functional colonies whose size is controlled by the extent of permanent crosslinks. With increasing stiffness and elastic response to deformation of the matrix, a decrease in colony volumes and an increase in their sphericity are observed. Protein production follows a different pattern with higher production yields occurring in networks with intermediate permanent crosslinking degrees. These results demonstrate that matrix design can be used to control and regulate the composition and function of ELMs containing microorganisms. Interestingly, design parameters for matrices to regulate bacteria behavior show similarities to those elucidated for 3D culture of mammalian cells.
68.

Bifunctional optogenetic switch for improving shikimic acid production in E. coli.

blue VVD E. coli Transgene expression
Biotechnol Biofuels, 7 Feb 2022 DOI: 10.1186/s13068-022-02111-3 Link to full text
Abstract: Background Biomass formation and product synthesis decoupling have been proven to be promising to increase the titer of desired value add products. Optogenetics provides a potential strategy to develop light-induced circuits that conditionally control metabolic flux redistribution for enhanced microbial production. However, the limited number of light-sensitive proteins available to date hinders the progress of light-controlled tools. Results To address these issues, two optogenetic systems (TPRS and TPAS) were constructed by reprogramming the widely used repressor TetR and protease TEVp to expand the current optogenetic toolkit. By merging the two systems, a bifunctional optogenetic switch was constructed to enable orthogonally regulated gene transcription and protein accumulation. Application of this bifunctional switch to decouple biomass formation and shikimic acid biosynthesis allowed 35 g/L of shikimic acid production in a minimal medium from glucose, representing the highest titer reported to date by E. coli without the addition of any chemical inducers and expensive aromatic amino acids. This titer was further boosted to 76 g/L when using rich medium fermentation. Conclusion The cost effective and light-controlled switch reported here provides important insights into environmentally friendly tools for metabolic pathway regulation and should be applicable to the production of other value-add chemicals.
69.

Development of Optogenetic Dual-Switch System for Rewiring Metabolic Flux for Polyhydroxybutyrate Production.

blue green CcaS/CcaR EL222 RsLOV YtvA E. coli Transgene expression
Molecules, 18 Jan 2022 DOI: 10.3390/molecules27030617 Link to full text
Abstract: Several strategies, including inducer addition and biosensor use, have been developed for dynamical regulation. However, the toxicity, cost, and inflexibility of existing strategies have created a demand for superior technology. In this study, we designed an optogenetic dual-switch system and applied it to increase polyhydroxybutyrate (PHB) production. First, an optimized chromatic acclimation sensor/regulator (RBS10-CcaS#10-CcaR) system (comprising an optimized ribosomal binding site (RBS), light sensory protein CcaS, and response regulator CcaR) was selected for a wide sensing range of approximately 10-fold between green-light activation and red-light repression. The RBS10-CcaS#10-CcaR system was combined with a blue light-activated YF1-FixJ-PhlF system (containing histidine kinase YF1, response regulator FixJ, and repressor PhlF) engineered with reduced crosstalk. Finally, the optogenetic dual-switch system was used to rewire the metabolic flux for PHB production by regulating the sequences and intervals of the citrate synthase gene (gltA) and PHB synthesis gene (phbCAB) expression. Consequently, the strain RBS34, which has high gltA expression and a time lag of 3 h, achieved the highest PHB content of 16.6 wt%, which was approximately 3-fold that of F34 (expressed at 0 h). The results indicate that the optogenetic dual-switch system was verified as a practical and convenient tool for increasing PHB production.
70.

Analysis of Three Architectures for Controlling PTP1B with Light.

blue AsLOV2 LOVTRAP Cos-7 E. coli HEK293T Transgene expression
ACS Synth Biol, 13 Dec 2021 DOI: 10.1021/acssynbio.1c00398 Link to full text
Abstract: Photosensory domains are powerful tools for placing proteins under optical control, but their integration into light-sensitive chimeras is often challenging. Many designs require structural iterations, and direct comparisons of alternative approaches are rare. This study uses protein tyrosine phosphatase 1B (PTP1B), an influential regulatory enzyme, to compare three architectures for controlling PTPs with light: a protein fusion, an insertion chimera, and a split construct. All three designs permitted optical control of PTP1B activity in vitro (i.e., kinetic assays of purified enzyme) and in mammalian cells; photoresponses measured under both conditions, while different in magnitude, were linearly correlated. The fusion- and insertion-based architectures exhibited the highest dynamic range and maintained native localization patterns in mammalian cells. A single insertion architecture enabled optical control of both PTP1B and TCPTP, but not SHP2, where the analogous chimera was active but not photoswitchable. Findings suggest that PTPs are highly tolerant of domain insertions and support the use of in vitro screens to evaluate different optogenetic designs.
71.

NIR light-responsive bacteria with live bio-glue coatings for precise colonization in the gut.

blue YtvA E. coli Signaling cascade control Transgene expression
Cell Rep, 14 Sep 2021 DOI: 10.1016/j.celrep.2021.109690 Link to full text
Abstract: Recombinant bacterial colonization plays an indispensable role in disease prevention, alleviation, and treatment. Successful application mainly depends on whether bacteria can efficiently spatiotemporally colonize the host gut. However, a primary limitation of existing methods is the lack of precise spatiotemporal regulation, resulting in uncontrolled methods that are less effective. Herein, we design upconversion microgels (UCMs) to convert near-infrared light (NIR) into blue light to activate recombinant light-responsive bacteria (Lresb) in vivo, where autocrine "functional cellular glues" made of adhesive proteins assist Lresb inefficiently colonizing the gut. The programmable engineering platform is further developed for the controlled and effective colonization of Escherichia coli Nissle 1917 (EcN) in the gut. The colonizing bacteria effectively alleviate DSS-induced colitis in mice. We anticipate that this approach could facilitate the clinical application of engineered microbial therapeutics to accurately and effectively regulate host health.
72.

Optogenetic Control of Microbial Consortia Populations for Chemical Production.

blue YtvA E. coli S. cerevisiae Transgene expression
ACS Synth Biol, 5 Aug 2021 DOI: 10.1021/acssynbio.1c00182 Link to full text
Abstract: Microbial 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 subpopulations for maximal chemical production remains a major obstacle in the field. In this study, we demonstrate that optogenetics is an effective strategy to dynamically control populations in microbial co-cultures. Using a new optogenetic circuit we call OptoTA, we regulate an endogenous toxin-antitoxin system, enabling tunability of Escherichia coli growth using only blue light. With this system we can control the population composition of co-cultures of E. coli and Saccharomyces cerevisiae. When introducing in each strain different metabolic modules of biosynthetic pathways for isobutyl acetate or naringenin, we found that the productivity of co-cultures increases by adjusting the population ratios with specific light duty cycles. This study shows the feasibility of using optogenetics to control microbial consortia populations and the advantages of using light to control their chemical production.
73.

Engineered NIR light-responsive bacteria as anti-tumor agent for targeted and precise cancer therapy.

blue EL222 E. coli Signaling cascade control
Lancet Infect Dis, 5 Jul 2021 DOI: 10.1016/j.cej.2021.130842 Link to full text
Abstract: Engineered anaerobic bacteria known as live biotherapeutic products (LBPs) have shown great advances in cancer therapy. One advantage of anaerobic bacteria as drug carrier is that it spontaneously target to tumor and persistently release anti-tumor factors. To realize effective anti-cancer therapeutics, one essential premise is to improve the controllability of treatment. Here, we designed near-infrared (NIR)-light responsive bacteria as anti-tumor agent, which is based on a blue-light responsive module and upconversion nanoparticles. The upconversion nanoparticles converted external NIR light to local blue light to noninvasively activate blue-light responsive module (EL222) in engineered LBPs. The activated LBPs then produce tumor necrosis factor α (TNFα) for precise tumor ablation. In vitro and in vivo results have proven that this engineered NIR-light-responsive bacteria could efficiently inhibit tumor growth. We anticipate that this controllable and safe bacteria-based therapy can facilitate the application of LBPs to accurately and effectively regulate diseases.
74.

Single-component near-infrared optogenetic systems for gene transcription regulation.

red iLight E. coli HeLa mouse in vivo primary mouse hippocampal neurons Transgene expression
Nat Commun, 23 Jun 2021 DOI: 10.1038/s41467-021-24212-7 Link to full text
Abstract: Near-infrared (NIR) optogenetic systems for transcription regulation are in high demand because NIR light exhibits low phototoxicity, low scattering, and allows combining with probes of visible range. However, available NIR optogenetic systems consist of several protein components of large size and multidomain structure. Here, we engineer single-component NIR systems consisting of evolved photosensory core module of Idiomarina sp. bacterial phytochrome, named iLight, which are smaller and packable in adeno-associated virus. We characterize iLight in vitro and in gene transcription repression in bacterial and gene transcription activation in mammalian cells. Bacterial iLight system shows 115-fold repression of protein production. Comparing to multi-component NIR systems, mammalian iLight system exhibits higher activation of 65-fold in cells and faster 6-fold activation in deep tissues of mice. Neurons transduced with viral-encoded iLight system exhibit 50-fold induction of fluorescent reporter. NIR light-induced neuronal expression of green-light-activatable CheRiff channelrhodopsin causes 20-fold increase of photocurrent and demonstrates efficient spectral multiplexing.
75.

mem-iLID, a fast and economic protein purification method.

blue bPAC (BlaC) iLID E. coli Xenopus oocytes
Biosci Rep, 18 Jun 2021 DOI: 10.1042/bsr20210800 Link to full text
Abstract: Protein purification is the vital basis to study the function, structure and interaction of proteins. Widely used methods are affinity chromatography-based purifications, which require different chromatography columns and harsh conditions, such as acidic pH and/or adding imidazole or high salt concentration, to elute and collect the purified proteins. Here we established an easy and fast purification method for soluble proteins under mild conditions, based on the light-induced protein dimerization system iLID, which regulates protein binding and release with light. We utilize the biological membrane, which can be easily separated by centrifugation, as the port to anchor the target proteins. In Xenopus laevis oocyte and Escherichia coli, the blue light-sensitive part of iLID, AsLOV2-SsrA, was targeted to the plasma membrane by different membrane anchors. The other part of iLID, SspB, was fused with the protein of interest (POI) and expressed in the cytosol. The SspB-POI can be captured to the membrane fraction through light-induced binding to AsLOV2-SsrA and then released purely to fresh buffer in the dark after simple centrifugation and washing. This method, named mem-iLID, is very flexible in scale and economic. We demonstrate the quickly obtained yield of two pure and fully functional enzymes: a DNA polymerase and a light-activated adenylyl cyclase. Furthermore, we also designed a new SspB mutant for better dissociation and less interference with the protein of interest, which could potentially facilitate other optogenetic manipulations of protein-protein interaction.
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