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Komera I, Chen X, Liu L, Gao C. Microbial Synthetic Epigenetic Tools Design and Applications. ACS Synth Biol 2024; 13:1621-1632. [PMID: 38758631 DOI: 10.1021/acssynbio.4c00125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/19/2024]
Abstract
Microbial synthetic epigenetics offers significant opportunities for the design of synthetic biology tools by leveraging reversible gene control mechanisms without altering DNA sequences. However, limited understanding and a lack of technologies for thorough analysis of the mechanisms behind epigenetic modifications have hampered their utilization in biotechnological applications. In this review, we explore advancements in developing epigenetic-based synthetic gene regulatory tools at both transcriptional and post-transcriptional levels. Furthermore, we examine strategies developed to construct epigenetic-based circuits that provide controllable and stable gene regulation, aiming to boost the performance of microbial chassis cells. Finally, we discuss the current challenges and perspectives in the development of synthetic epigenetic tools.
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Affiliation(s)
- Irene Komera
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Xiulai Chen
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
| | - Cong Gao
- School of Biotechnology and Key Laboratory of Industrial Biotechnology of Ministry of Education, Jiangnan University, Wuxi 214122, China
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2
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Kompaniiets D, Wang D, Yang Y, Hu Y, Liu B. Structure and molecular mechanism of bacterial transcription activation. Trends Microbiol 2024; 32:379-397. [PMID: 37903670 DOI: 10.1016/j.tim.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/27/2023] [Accepted: 10/03/2023] [Indexed: 11/01/2023]
Abstract
Transcription activation is an important checkpoint of regulation of gene expression which occurs in response to different intracellular and extracellular signals. The key elements in this signal transduction process are transcription activators, which determine when and how gene expression is activated. Recent structural studies on a considerable number of new transcription activation complexes (TACs) revealed the remarkable mechanistic diversity of transcription activation mediated by different factors, necessitating a review and re-evaluation of the transcription activation mechanisms. In this review, we present a comprehensive summary of transcription activation mechanisms and propose a new, elaborate, and systematic classification of transcription activation mechanisms, primarily based on the structural features of diverse TAC components.
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Affiliation(s)
- Dmytro Kompaniiets
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Dong Wang
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Yang Yang
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Yangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Bin Liu
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA.
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3
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Lee-Lopez C, Islam MS, Meléndez AB, Yukl ET. Influence of the Heme Nitric Oxide/Oxygen Binding Protein (H-NOX) on Cell Cycle Regulation in Caulobacter crescentus. Mol Cell Proteomics 2023; 22:100679. [PMID: 37979947 PMCID: PMC10746521 DOI: 10.1016/j.mcpro.2023.100679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2023] [Accepted: 10/29/2023] [Indexed: 11/20/2023] Open
Abstract
The ability of an organism to respond to environmental changes is paramount to survival across a range of conditions. The bacterial heme nitric oxide/oxygen binding proteins (H-NOX) are a family of biofilm-regulating gas sensors that enable bacteria to respond accordingly to the cytotoxic molecule nitric oxide. By interacting with downstream signaling partners, H-NOX regulates the production of the bacterial secondary messenger cyclic diguanylate monophosphate (c-di-GMP) to influence biofilm formation. The aquatic organism Caulobacter crescentus has the propensity to attach to surfaces as part of its transition into the stalked S-phase of its life cycle. This behavior is heavily influenced by intracellular c-di-GMP and thus poses H-NOX as a potential influencer of C. crescentus surface attachment and cell cycle. By generating a strain of C. crescentus lacking hnox, our laboratory has demonstrated that this strain exhibits a considerable growth deficit, an increase in biofilm formation, and an elevation in c-di-GMP. Furthermore, in our comprehensive proteome study of 2779 proteins, 236 proteins were identified that exhibited differential expression in Δhnox C. crescentus, with 132 being downregulated and 104 being upregulated, as determined by a fold change of ≥1.5 or ≤0.66 and a p value ≤0.05. Our systematic analysis unveiled several regulated candidates including GcrA, PopA, RsaA, FtsL, DipM, FlgC, and CpaE that are associated with the regulation of the cellular division process, surface proteins, flagellum, and pili assembly. Further examination of Gene Ontology and pathways indicated that the key differences could be attributed to several metabolic processes. Taken together, our data indicate a role for the HNOX protein in C. crescentus cell cycle progression.
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Affiliation(s)
- Cameron Lee-Lopez
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, USA
| | - Md Shariful Islam
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, USA; Department of Mathematics and Physics, North South University, Dhaka, Bangladesh
| | - Ady B Meléndez
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, USA
| | - Erik T Yukl
- Department of Chemistry and Biochemistry, New Mexico State University, Las Cruces, New Mexico, USA.
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4
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Shepherd MJ, Pierce AP, Taylor TB. Evolutionary innovation through transcription factor rewiring in microbes is shaped by levels of transcription factor activity, expression, and existing connectivity. PLoS Biol 2023; 21:e3002348. [PMID: 37871011 PMCID: PMC10621929 DOI: 10.1371/journal.pbio.3002348] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2023] [Revised: 11/02/2023] [Accepted: 09/25/2023] [Indexed: 10/25/2023] Open
Abstract
The survival of a population during environmental shifts depends on whether the rate of phenotypic adaptation keeps up with the rate of changing conditions. A common way to achieve this is via change to gene regulatory network (GRN) connections-known as rewiring-that facilitate novel interactions and innovation of transcription factors. To understand the success of rapidly adapting organisms, we therefore need to determine the rules that create and constrain opportunities for GRN rewiring. Here, using an experimental microbial model system with the soil bacterium Pseudomonas fluorescens, we reveal a hierarchy among transcription factors that are rewired to rescue lost function, with alternative rewiring pathways only unmasked after the preferred pathway is eliminated. We identify 3 key properties-high activation, high expression, and preexisting low-level affinity for novel target genes-that facilitate transcription factor innovation. Ease of acquiring these properties is constrained by preexisting GRN architecture, which was overcome in our experimental system by both targeted and global network alterations. This work reveals the key properties that determine transcription factor evolvability, and as such, the evolution of GRNs.
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Affiliation(s)
- Matthew J. Shepherd
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, United Kingdom
| | - Aidan P. Pierce
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
| | - Tiffany B. Taylor
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Bath, United Kingdom
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5
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Alakavuklar MA, Fiebig A, Crosson S. The Brucella Cell Envelope. Annu Rev Microbiol 2023; 77:233-253. [PMID: 37104660 PMCID: PMC10787603 DOI: 10.1146/annurev-micro-032521-013159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/29/2023]
Abstract
The cell envelope is a multilayered structure that insulates the interior of bacterial cells from an often chaotic outside world. Common features define the envelope across the bacterial kingdom, but the molecular mechanisms by which cells build and regulate this critical barrier are diverse and reflect the evolutionary histories of bacterial lineages. Intracellular pathogens of the genus Brucella exhibit marked differences in cell envelope structure, regulation, and biogenesis when compared to more commonly studied gram-negative bacteria and therefore provide an excellent comparative model for study of the gram-negative envelope. We review distinct features of the Brucella envelope, highlighting a conserved regulatory system that links cell cycle progression to envelope biogenesis and cell division. We further discuss recently discovered structural features of the Brucella envelope that ensure envelope integrity and that facilitate cell survival in the face of host immune stressors.
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Affiliation(s)
- Melene A Alakavuklar
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Aretha Fiebig
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
| | - Sean Crosson
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, Michigan, USA;
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Komera I, Gao C, Chen X, Chen W, Liu L. Synthetic epigenetics-assisted microbial chassis engineering. Trends Microbiol 2023; 31:889-893. [PMID: 37400289 DOI: 10.1016/j.tim.2023.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 07/05/2023]
Abstract
Microbial chassis engineering is the milestone of efficient biotechnological applications. However, microbial chassis cell engineering is adversely affected by (i) regulatory tool orthogonality, (ii) host metabolic fitness, and (iii) cell population heterogeneity. Herein, we explore how synthetic epigenetics can potentially address these limitations and offer insights into prospects in this field.
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Affiliation(s)
- Irene Komera
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| | - Cong Gao
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| | - Xiulai Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China
| | - Wei Chen
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China
| | - Liming Liu
- State Key Laboratory of Food Science and Resources, Jiangnan University, Wuxi 214122, China; International Joint Laboratory on Food Safety, Jiangnan University, Wuxi 214122, China.
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7
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Shepherd MJ, Reynolds M, Pierce AP, Rice AM, Taylor TB. Transcription factor expression levels and environmental signals constrain transcription factor innovation. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001378. [PMID: 37584667 PMCID: PMC10482368 DOI: 10.1099/mic.0.001378] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Accepted: 07/26/2023] [Indexed: 08/17/2023]
Abstract
Evolutionary innovation of transcription factors frequently drives phenotypic diversification and adaptation to environmental change. Transcription factors can gain or lose connections to target genes, resulting in novel regulatory responses and phenotypes. However the frequency of functional adaptation varies between different regulators, even when they are closely related. To identify factors influencing propensity for innovation, we utilise a Pseudomonas fluorescens SBW25 strain rendered incapable of flagellar mediated motility in soft-agar plates via deletion of the flagellar master regulator (fleQ ). This bacterium can evolve to rescue flagellar motility via gene regulatory network rewiring of an alternative transcription factor to rescue activity of FleQ. Previously, we have identified two members (out of 22) of the RpoN-dependent enhancer binding protein (RpoN-EBP) family of transcription factors (NtrC and PFLU1132) that are capable of innovating in this way. These two transcription factors rescue motility repeatably and reliably in a strict hierarchy – with NtrC the only route in a ∆fleQ background, and PFLU1132 the only route in a ∆fleQ ∆ntrC background. However, why other members in the same transcription factor family have not been observed to rescue flagellar activity is unclear. Previous work shows that protein homology cannot explain this pattern within the protein family (RpoN-EBPs), and mutations in strains that rescued motility suggested high levels of transcription factor expression and activation drive innovation. We predict that mutations that increase expression of the transcription factor are vital to unlock evolutionary potential for innovation. Here, we construct titratable expression mutant lines for 11 of the RpoN-EBPs in P. fluorescens . We show that in five additional RpoN-EBPs (FleR, HbcR, GcsR, DctD, AauR and PFLU2209), high expression levels result in different mutations conferring motility rescue, suggesting alternative rewiring pathways. Our results indicate that expression levels (and not protein homology) of RpoN-EBPs are a key constraining factor in determining evolutionary potential for innovation. This suggests that transcription factors that can achieve high expression through few mutational changes, or transcription factors that are active in the selective environment, are more likely to innovate and contribute to adaptive gene regulatory network evolution.
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Affiliation(s)
- Matthew J. Shepherd
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
- Division of Evolution and Genomic Sciences, School of Biological Sciences, University of Manchester, Manchester, UK
| | - Mitchell Reynolds
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Aidan P. Pierce
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Alan M. Rice
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
| | - Tiffany B. Taylor
- Milner Centre for Evolution, Department of Life Sciences, University of Bath, Claverton Down, Bath BA2 7AY, UK
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Wu X, Yu C, Mu W, Gu Z, Feng Y, Zhang Y. The structural mechanism for transcription activation by Caulobacter crescentus GcrA. Nucleic Acids Res 2023; 51:1960-1970. [PMID: 36715319 PMCID: PMC9976885 DOI: 10.1093/nar/gkad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/28/2022] [Accepted: 01/05/2023] [Indexed: 01/31/2023] Open
Abstract
Canonical bacterial transcription activators bind to their cognate cis elements at the upstream of transcription start site (TSS) in a form of dimer. Caulobacter crescentus GcrA, a non-canonical transcription activator, can activate transcription from promoters harboring its cis element at the upstream or downstream of TSS in a form of monomer. We determined two cryo-EM structures of C. crescentus GcrA-bound transcription activation complexes, GcrA TACU and GcrA TACD, which comprise GcrA, RNAP, σ70 and promoter DNA with GcrA cis elements at either the upstream or downstream of TSS at 3.6 and 3.8 Å, respectively. In the GcrA-TACU structure, GcrA makes bipartite interactions with both σ70 domain 2 (σ702) and its cis element, while in the GcrA-TACD structure, GcrA retains interaction with σ702 but loses the interaction with its cis element. Our results suggest that GcrA likely forms a functionally specialized GcrA-RNAP-σA holoenzyme, in which GcrA first locates its cis element and then facilitates RNAP to load on core promoter at its proximal region. The sequence-specific interaction of GcrA and DNA is disrupted either at the stage of RPo formation or promoter escape depending on the location of GcrA cis elements relative to TSS.
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Affiliation(s)
- Xiaoxian Wu
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chengzhi Yu
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenhui Mu
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Zhanxi Gu
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Feng
- Department of Biophysics, and Department of Infectious Disease of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
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9
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DNA Methylation in
Ensifer
Species during Free-Living Growth and during Nitrogen-Fixing Symbiosis with
Medicago
spp. mSystems 2022; 7:e0109221. [PMID: 35089065 PMCID: PMC8725594 DOI: 10.1128/msystems.01092-21] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
Nitrogen fixation by rhizobia in symbiosis with legumes is economically and ecologically important. The symbiosis can involve a complex bacterial transformation—terminal differentiation—that includes major shifts in the transcriptome and cell cycle.
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10
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Mascolo E, Adhikari S, Caruso SM, deCarvalho T, Folch Salvador A, Serra-Sagristà J, Young R, Erill I, Curtis PD. The transcriptional regulator CtrA controls gene expression in Alphaproteobacteria phages: Evidence for a lytic deferment pathway. Front Microbiol 2022; 13:918015. [PMID: 36060776 PMCID: PMC9437464 DOI: 10.3389/fmicb.2022.918015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Accepted: 07/18/2022] [Indexed: 11/13/2022] Open
Abstract
Pilitropic and flagellotropic phages adsorb to bacterial pili and flagella. These phages have long been used to investigate multiple aspects of bacterial physiology, such as the cell cycle control in the Caulobacterales. Targeting cellular appendages for adsorption effectively constrains the population of infectable hosts, suggesting that phages may have developed strategies to maximize their infective yield. Brevundimonas phage vB_BsubS-Delta is a recently characterized pilitropic phage infecting the Alphaproteobacterium Brevundimonas subvibrioides. Like other Caulobacterales, B. subvibrioides divides asymmetrically and its cell cycle is governed by multiple transcriptional regulators, including the master regulator CtrA. Genomic characterization of phage vB_BsubS-Delta identified the presence of a large intergenic region with an unusually high density of putative CtrA-binding sites. A systematic analysis of the positional distribution of predicted CtrA-binding sites in complete phage genomes reveals that the highly skewed distribution of CtrA-binding sites observed in vB_BsubS-Delta is an unequivocal genomic signature that extends to other pilli- and flagellotropic phages infecting the Alphaproteobacteria. Moreover, putative CtrA-binding sites in these phage genomes localize preferentially to promoter regions and have higher scores than those detected in other phage genomes. Phylogenetic and comparative genomics analyses show that this genomic signature has evolved independently in several phage lineages, suggesting that it provides an adaptive advantage to pili/flagellotropic phages infecting the Alphaproteobacteria. Experimental results demonstrate that CtrA binds to predicted CtrA-binding sites in promoter regions and that it regulates transcription of phage genes in unrelated Alphaproteobacteria-infecting phages. We propose that this focused distribution of CtrA-binding sites reflects a fundamental new aspect of phage infection, which we term lytic deferment. Under this novel paradigm, pili- and flagellotropic phages exploit the CtrA transduction pathway to monitor the host cell cycle state and synchronize lysis with the presence of infectable cells.
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Affiliation(s)
- Elia Mascolo
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, United States
| | - Satish Adhikari
- Department of Biology, University of Mississippi, Oxford, MS, United States
| | - Steven M Caruso
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, United States
| | - Tagide deCarvalho
- Keith R. Porter Imaging Facility, College of Natural and Mathematical Sciences, University of Maryland Baltimore County (UMBC), Baltimore, MD, United States
| | | | | | - Ry Young
- Center for Phage Technology, Texas A&M University, College Station, TX, United States
| | - Ivan Erill
- Department of Biological Sciences, University of Maryland Baltimore County, Baltimore, MD, United States
| | - Patrick D Curtis
- Department of Biology, University of Mississippi, Oxford, MS, United States
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