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Boo A, Toth T, Yu Q, Pfotenhauer A, Fields BD, Lenaghan SC, Stewart CN, Voigt CA. Synthetic microbe-to-plant communication channels. Nat Commun 2024; 15:1817. [PMID: 38418817 PMCID: PMC10901793 DOI: 10.1038/s41467-024-45897-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 02/07/2024] [Indexed: 03/02/2024] Open
Abstract
Plants and microbes communicate to collaborate to stop pests, scavenge nutrients, and react to environmental change. Microbiota consisting of thousands of species interact with each other and plants using a large chemical language that is interpreted by complex regulatory networks. In this work, we develop modular interkingdom communication channels, enabling bacteria to convey environmental stimuli to plants. We introduce a "sender device" in Pseudomonas putida and Klebsiella pneumoniae, that produces the small molecule p-coumaroyl-homoserine lactone (pC-HSL) when the output of a sensor or circuit turns on. This molecule triggers a "receiver device" in the plant to activate gene expression. We validate this system in Arabidopsis thaliana and Solanum tuberosum (potato) grown hydroponically and in soil, demonstrating its modularity by swapping bacteria that process different stimuli, including IPTG, aTc and arsenic. Programmable communication channels between bacteria and plants will enable microbial sentinels to transmit information to crops and provide the building blocks for designing artificial consortia.
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Affiliation(s)
- Alice Boo
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tyler Toth
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Qiguo Yu
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Alexander Pfotenhauer
- Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Brandon D Fields
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Scott C Lenaghan
- Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - C Neal Stewart
- Center for Agricultural Synthetic Biology, University of Tennessee, Knoxville, TN, 37996, USA
| | - Christopher A Voigt
- Department of Biological Engineering, Synthetic Biology Center, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
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Triassi AJ, Fields BD, Monahan CE, Means JM, Park Y, Doosthosseini H, Padmakumar JP, Isabella VM, Voigt CA. Redesign of an Escherichia coli Nissle treatment for phenylketonuria using insulated genomic landing pads and genetic circuits to reduce burden. Cell Syst 2023; 14:512-524.e12. [PMID: 37348465 DOI: 10.1016/j.cels.2023.05.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2021] [Revised: 01/18/2023] [Accepted: 05/19/2023] [Indexed: 06/24/2023]
Abstract
To build therapeutic strains, Escherichia coli Nissle (EcN) have been engineered to express antibiotics, toxin-degrading enzymes, immunoregulators, and anti-cancer chemotherapies. For efficacy, the recombinant genes need to be highly expressed, but this imposes a burden on the cell, and plasmids are difficult to maintain in the body. To address these problems, we have developed landing pads in the EcN genome and genetic circuits to control therapeutic gene expression. These tools were applied to EcN SYNB1618, undergoing clinical trials as a phenylketonuria treatment. The pathway for converting phenylalanine to trans-cinnamic acid was moved to a landing pad under the control of a circuit that keeps the pathway off during storage. The resulting strain (EcN SYN8784) achieved higher activity than EcN SYNB1618, reaching levels near when the pathway is carried on a plasmid. This work demonstrates a simple system for engineering EcN that aids quantitative strain design for therapeutics.
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Affiliation(s)
- Alexander J Triassi
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Brandon D Fields
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | | | - Yongjin Park
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Hamid Doosthosseini
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Jai P Padmakumar
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | | | - Christopher A Voigt
- Synthetic Biology Center, Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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Fields BD, Nguyen SC, Nir G, Kennedy S. A multiplexed DNA FISH strategy for assessing genome architecture in Caenorhabditis elegans. eLife 2019; 8:42823. [PMID: 31084706 PMCID: PMC6516958 DOI: 10.7554/elife.42823] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2018] [Accepted: 04/02/2019] [Indexed: 02/06/2023] Open
Abstract
Eukaryotic DNA is highly organized within nuclei and this organization is important for genome function. Fluorescent in situ hybridization (FISH) approaches allow 3D architectures of genomes to be visualized. Scalable FISH technologies, which can be applied to whole animals, are needed to help unravel how genomic architecture regulates, or is regulated by, gene expression during development, growth, reproduction, and aging. Here, we describe a multiplexed DNA FISH Oligopaint library that targets the entire Caenorhabditis elegans genome at chromosome, three megabase, and 500 kb scales. We describe a hybridization strategy that provides flexibility to DNA FISH experiments by coupling a single primary probe synthesis reaction to dye conjugated detection oligos via bridge oligos, eliminating the time and cost typically associated with labeling probe sets for individual experiments. The approach allows visualization of genome organization at varying scales in all/most cells across all stages of development in an intact animal model system. DNA contains the instructions needed to build and maintain a living organism. How DNA is physically arranged inside a cell is not random, and DNA organization is important because it can affect, for example, which genes are active, and which are not. Researchers often use a technique called “fluorescence in situ hybridization” (or FISH for short) to study how DNA is organized in cells. FISH tethers fluorescent molecules to defined sections of DNA, making those sections glow under the right wavelength of light. It is possible to collect images of the fluorescent DNA regions under a microscope to see where they are in relation to each other and to the rest of the cell. Fields, Nguyen et al. have now created a new library of FISH molecules that can be used to analyze the DNA of a microscopic worm known as Caenorhabditis elegans – a model organism that is widely used to study genetics, animal development, and cell biology. The library can be used to visualize the worm’s whole genome at different scales. The library enables accurate and reliable investigations of how DNA is organized inside C. elegans, including in intact worms, meaning it also offers the first chance to study DNA organization in a whole organism through all stages of its life cycle. This new resource could help to reveal the relationships between DNA organization, cell specialization and gene activity in different cells at different stages of development. This could help to clarify the relationships between physical DNA organization and biological change. This design strategy behind this whole genome library should also be adaptable for similar studies in other animal species.
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Affiliation(s)
- Brandon D Fields
- Laboratory of Genetics, University of Wisconsin-Madison, Madison, United States.,Department of Genetics, Harvard Medical School, Boston, United States
| | - Son C Nguyen
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Guy Nir
- Department of Genetics, Harvard Medical School, Boston, United States
| | - Scott Kennedy
- Department of Genetics, Harvard Medical School, Boston, United States
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Perales R, Pagano D, Wan G, Fields BD, Saltzman AL, Kennedy SG. Transgenerational Epigenetic Inheritance Is Negatively Regulated by the HERI-1 Chromodomain Protein. Genetics 2018; 210:1287-1299. [PMID: 30389807 PMCID: PMC6283161 DOI: 10.1534/genetics.118.301456] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2018] [Accepted: 10/23/2018] [Indexed: 12/31/2022] Open
Abstract
Transgenerational epigenetic inheritance (TEI) is the inheritance of epigenetic information for two or more generations. In most cases, TEI is limited to a small number of generations (two to three). The short-term nature of TEI could be set by innate biochemical limitations to TEI or by genetically encoded systems that actively limit TEI. In Caenorhabditis elegans, double-stranded RNA (dsRNA)-mediated gene silencing [RNAi (RNA interference)] can be inherited (termed RNAi inheritance or RNA-directed TEI). To identify systems that might actively limit RNA-directed TEI, we conducted a forward genetic screen for factors whose mutation enhanced RNAi inheritance. This screen identified the gene heritable enhancer of RNAi (heri-1), whose mutation causes RNAi inheritance to last longer (> 20 generations) than normal. heri-1 encodes a protein with a chromodomain, and a kinase homology domain that is expressed in germ cells and localizes to nuclei. In C. elegans, a nuclear branch of the RNAi pathway [termed the nuclear RNAi or NRDE (nuclear RNA defective) pathway] promotes RNAi inheritance. We find that heri-1(-) animals have defects in spermatogenesis that are suppressible by mutations in the nuclear RNAi Argonaute (Ago) HRDE-1, suggesting that HERI-1 might normally act in sperm progenitor cells to limit nuclear RNAi and/or RNAi inheritance. Consistent with this idea, we find that the NRDE nuclear RNAi pathway is hyperresponsive to experimental RNAi treatments in heri-1 mutant animals. Interestingly, HERI-1 binds to genes targeted by RNAi, suggesting that HERI-1 may have a direct role in limiting nuclear RNAi and, therefore, RNAi inheritance. Finally, the recruitment of HERI-1 to chromatin depends upon the same factors that drive cotranscriptional gene silencing, suggesting that the generational perdurance of RNAi inheritance in C. elegans may be set by competing pro- and antisilencing outputs of the nuclear RNAi machinery.
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Affiliation(s)
- Roberto Perales
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Daniel Pagano
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Gang Wan
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
| | - Brandon D Fields
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
- Laboratory of Genetics, University of Wisconsin-Madison, Wisconsin 53706
| | - Arneet L Saltzman
- Department of Cell and Systems Biology, University of Toronto, Ontario M5S 3G5, Canada
| | - Scott G Kennedy
- Department of Genetics, Harvard Medical School, Boston, Massachusetts 02115
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Wan G, Fields BD, Spracklin G, Shukla A, Phillips CM, Kennedy S. Spatiotemporal regulation of liquid-like condensates in epigenetic inheritance. Nature 2018; 557:679-683. [PMID: 29769721 PMCID: PMC6479227 DOI: 10.1038/s41586-018-0132-0] [Citation(s) in RCA: 111] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Accepted: 04/10/2018] [Indexed: 11/09/2022]
Abstract
Non-membrane bound organelles such as nucleoli, processing bodies, cajal bodies, and germ granules form via spontaneous self-assembly of specific proteins and RNAs. How these biomolecular condensates form and interact are poorly understood. Here we identify two proteins, ZNFX-1 and WAGO-4, that localize to C. elegans germ granules (P granules) in early germline blastomeres. Later in germline development, ZNFX-1/WAGO-4 separate from P granules to define an independent liquid-like condensate that we term the Z granule. In adult germ cells, Z granules assemble into ordered tri-condensate assemblages with P granules and Mutator foci, which we term the PZM granule. Finally, we show that one biological function of ZNFX-1 and WAGO-4 is to interact with silencing RNAs in the C. elegans germline to direct transgenerational epigenetic inheritance (TEI). We speculate that the temporal and spatial ordering of liquid droplet organelles may help cells organize and coordinate the complex RNA processing pathways underlying gene regulatory systems, such as RNA-directed TEI.
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Affiliation(s)
- Gang Wan
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Brandon D Fields
- Department of Genetics, Harvard Medical School, Boston, MA, USA.,Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - George Spracklin
- Department of Genetics, Harvard Medical School, Boston, MA, USA.,Laboratory of Genetics, University of Wisconsin-Madison, Madison, WI, USA
| | - Aditi Shukla
- Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Carolyn M Phillips
- Department of Biological Sciences, University of Southern California, Los Angeles, CA, USA
| | - Scott Kennedy
- Department of Genetics, Harvard Medical School, Boston, MA, USA.
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Etheridge T, Oczypok EA, Lehmann S, Fields BD, Shephard F, Jacobson LA, Szewczyk NJ. Calpains mediate integrin attachment complex maintenance of adult muscle in Caenorhabditis elegans. PLoS Genet 2012; 8:e1002471. [PMID: 22253611 PMCID: PMC3257289 DOI: 10.1371/journal.pgen.1002471] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2011] [Accepted: 11/23/2011] [Indexed: 11/23/2022] Open
Abstract
Two components of integrin containing attachment complexes, UNC-97/PINCH and UNC-112/MIG-2/Kindlin-2, were recently identified as negative regulators of muscle protein degradation and as having decreased mRNA levels in response to spaceflight. Integrin complexes transmit force between the inside and outside of muscle cells and signal changes in muscle size in response to force and, perhaps, disuse. We therefore investigated the effects of acute decreases in expression of the genes encoding these multi-protein complexes. We find that in fully developed adult Caenorhabditis elegans muscle, RNAi against genes encoding core, and peripheral, members of these complexes induces protein degradation, myofibrillar and mitochondrial dystrophies, and a movement defect. Genetic disruption of Z-line– or M-line–specific complex members is sufficient to induce these defects. We confirmed that defects occur in temperature-sensitive mutants for two of the genes: unc-52, which encodes the extra-cellular ligand Perlecan, and unc-112, which encodes the intracellular component Kindlin-2. These results demonstrate that integrin containing attachment complexes, as a whole, are required for proper maintenance of adult muscle. These defects, and collapse of arrayed attachment complexes into ball like structures, are blocked when DIM-1 levels are reduced. Degradation is also blocked by RNAi or drugs targeting calpains, implying that disruption of integrin containing complexes results in calpain activation. In wild-type animals, either during development or in adults, RNAi against calpain genes results in integrin muscle attachment disruptions and consequent sub-cellular defects. These results demonstrate that calpains are required for proper assembly and maintenance of integrin attachment complexes. Taken together our data provide in vivo evidence that a calpain-based molecular repair mechanism exists for dealing with attachment complex disruption in adult muscle. Since C. elegans lacks satellite cells, this mechanism is intrinsic to the muscles and raises the question if such a mechanism also exists in higher metazoans. Muscle is a dynamic tissue that grows in response to use and nutrition and shrinks in response to lack of use, poor nutrition, or disease. Loss of muscle mass is an important public health problem, but we understand little of the genes that regulate muscle shrinkage. We have found that, in adult worm muscle, attachment to the basement membrane is continuously required to prevent catastrophic sub-cellular defects that result in impaired ability of muscle to function. We have also identified a group of proteases that are activated when the attachment fails to be properly maintained. Conversely, when these proteases are lacking in adult muscle, the muscles fail to maintain attachment to the basement membrane. Thus, we have discovered a group of proteases that appear to act to maintain attachment to the basement membrane and therefore to maintain muscle itself. Because these worms lack satellite cells, this maintenance system is intrinsic to muscle, thus raising the question whether a similar or identical system also works in humans.
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Affiliation(s)
- Timothy Etheridge
- School of Graduate Entry Medicine and Health, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
| | - Elizabeth A. Oczypok
- School of Graduate Entry Medicine and Health, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Susann Lehmann
- School of Graduate Entry Medicine and Health, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
| | - Brandon D. Fields
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Freya Shephard
- School of Graduate Entry Medicine and Health, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
| | - Lewis A. Jacobson
- Department of Biological Sciences, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Nathaniel J. Szewczyk
- School of Graduate Entry Medicine and Health, University of Nottingham, Royal Derby Hospital, Derby, United Kingdom
- * E-mail:
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Affiliation(s)
- B D Fields
- Center for Theoretical Astrophysics, Department of Astronomy, University of Illinois, Urbana, IL 61801, USA.
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Ryan SG, Beers TC, Olive KA, Fields BD, Norris JE. Primordial Lithium and Big Bang Nucleosynthesis. Astrophys J 2000; 530:L57-L60. [PMID: 10655164 DOI: 10.1086/312492] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Recent determinations of the abundance of the light-element Li in very metal-poor stars show that its intrinsic dispersion is essentially zero and that the random error in the estimated mean Li abundance is negligible. However, a decreasing trend in the Li abundance toward lower metallicity indicates that the primordial abundance of Li can be inferred only after allowing for nucleosynthesis processes that must have been in operation in the early history of the Galaxy. We show that the observed Li versus Fe trend provides a strong discriminant between alternative models for Galactic chemical evolution of the light elements at early epochs. We critically assess current systematic uncertainties and determine the primordial Li abundance within new, much tighter limits: &parl0;Li&solm0;H&parr0;p=1.23+0.68-0.32x10-10. We show that the Li constraint on OmegaB is now limited as much by uncertainties in the nuclear cross sections used in big bang nucleosynthesis (BBN) calculations as by the observed abundance itself. A clearer understanding of systematics allows us to sharpen the comparison with 4He and deuterium and the resulting test of BBN.
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Shi X, Schramm DN, Fields BD. Constraints on neutrino oscillations from big bang nucleosynthesis. Phys Rev D Part Fields 1993; 48:2563-2572. [PMID: 10016504 DOI: 10.1103/physrevd.48.2563] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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Fields BD, Dodelson S, Turner MS. Effect of neutrino heating on primordial nucleosynthesis. Phys Rev D Part Fields 1993; 47:4309-4314. [PMID: 10015430 DOI: 10.1103/physrevd.47.4309] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
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