1
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Herdman M, Isbilir B, von Kügelgen A, Schulze U, Wainman A, Bharat TAM. Cell cycle dependent coordination of surface layer biogenesis in Caulobacter crescentus. Nat Commun 2024; 15:3355. [PMID: 38637514 PMCID: PMC11026435 DOI: 10.1038/s41467-024-47529-5] [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: 06/23/2023] [Accepted: 04/04/2024] [Indexed: 04/20/2024] Open
Abstract
Surface layers (S-layers) are proteinaceous, two-dimensional paracrystalline arrays that constitute a major component of the cell envelope in many prokaryotic species. In this study, we investigated S-layer biogenesis in the bacterial model organism Caulobacter crescentus. Fluorescence microscopy revealed localised incorporation of new S-layer at the poles and mid-cell, consistent with regions of cell growth in the cell cycle. Light microscopy and electron cryotomography investigations of drug-treated bacteria revealed that localised S-layer insertion is retained when cell division is inhibited, but is disrupted upon dysregulation of MreB or lipopolysaccharide. We further uncovered that S-layer biogenesis follows new peptidoglycan synthesis and localises to regions of high cell wall turnover. Finally, correlated cryo-light microscopy and electron cryotomographic analysis of regions of S-layer insertion showed the presence of discontinuities in the hexagonal S-layer lattice, contrasting with other S-layers completed by defined symmetric defects. Our findings present insights into how C. crescentus cells form an ordered S-layer on their surface in coordination with the biogenesis of other cell envelope components.
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Affiliation(s)
- Matthew Herdman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Buse Isbilir
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Andriko von Kügelgen
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Ulrike Schulze
- Cell Biology Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK
| | - Alan Wainman
- Sir William Dunn School of Pathology, University of Oxford, Oxford, OX1 3RE, UK
| | - Tanmay A M Bharat
- Structural Studies Division, MRC Laboratory of Molecular Biology, Cambridge, CB2 0QH, UK.
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2
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Nandana V, Rathnayaka-Mudiyanselage IW, Muthunayake NS, Hatami A, Mousseau CB, Ortiz-Rodríguez LA, Vaishnav J, Collins M, Gega A, Mallikaarachchi KS, Yassine H, Ghosh A, Biteen JS, Zhu Y, Champion MM, Childers WS, Schrader JM. The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions. Cell Rep 2023; 42:113229. [PMID: 37815915 PMCID: PMC10842194 DOI: 10.1016/j.celrep.2023.113229] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Revised: 07/16/2023] [Accepted: 09/22/2023] [Indexed: 10/12/2023] Open
Abstract
Bacterial ribonucleoprotein bodies (BR-bodies) are non-membrane-bound structures that facilitate mRNA decay by concentrating mRNA substrates with RNase E and the associated RNA degradosome machinery. However, the full complement of proteins enriched in BR-bodies has not been defined. Here, we define the protein components of BR-bodies through enrichment of the bodies followed by mass spectrometry-based proteomic analysis. We find 111 BR-body-enriched proteins showing that BR-bodies are more complex than previously assumed. We identify five BR-body-enriched proteins that undergo RNA-dependent phase separation in vitro with a complex network of condensate mixing. We observe that some RNP condensates co-assemble with preferred directionality, suggesting that RNA may be trafficked through RNP condensates in an ordered manner to facilitate mRNA processing/decay, and that some BR-body-associated proteins have the capacity to dissolve the condensate. Altogether, these results suggest that a complex network of protein-protein and protein-RNA interactions controls BR-body phase separation and RNA processing.
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Affiliation(s)
- Vidhyadhar Nandana
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Imalka W Rathnayaka-Mudiyanselage
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA; Department of Chemistry, Wayne State University, Detroit, MI 48202, USA
| | | | - Ali Hatami
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - C Bruce Mousseau
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | | | - Jamuna Vaishnav
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Michael Collins
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Alisa Gega
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | | | - Hadi Yassine
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Aishwarya Ghosh
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Yingxi Zhu
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI 48202, USA
| | - Matthew M Champion
- Department of Chemistry, University of Notre Dame, Notre Dame, IN 46556, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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3
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Nandana V, Rathnayaka-Mudiyanselage IW, Muthunayak NS, Hatami A, Mousseau CB, Ortiz-Rodríguez LA, Vaishnav J, Collins M, Gega A, Mallikaarachchi KS, Yassine H, Ghosh A, Biteen JS, Zhu Y, Champion MM, Childers WS, Schrader JM. The BR-body proteome contains a complex network of protein-protein and protein-RNA interactions. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.18.524314. [PMID: 36712072 PMCID: PMC9882336 DOI: 10.1101/2023.01.18.524314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Bacterial RNP bodies (BR-bodies) are non-membrane-bound structures that facilitate mRNA decay by concentrating mRNA substrates with RNase E and the associated RNA degradosome machinery. However, the full complement of proteins enriched in BR-bodies has not been defined. Here we define the protein components of BR-bodies through enrichment of the bodies followed by mass spectrometry-based proteomic analysis. We found 111 BR-body enriched proteins, including several RNA binding proteins, many of which are also recruited directly to in vitro reconstituted RNase E droplets, showing BR-bodies are more complex than previously assumed. While most BR-body enriched proteins that were tested cannot phase separate, we identified five that undergo RNA-dependent phase separation in vitro, showing other RNP condensates interface with BR-bodies. RNA degradosome protein clients are recruited more strongly to RNase E droplets than droplets of other RNP condensates, implying that client specificity is largely achieved through direct protein-protein interactions. We observe that some RNP condensates assemble with preferred directionally, suggesting that RNA may be trafficked through RNP condensates in an ordered manner to facilitate mRNA processing/decay, and that some BR-body associated proteins have the capacity to dissolve the condensate. Finally, we find that RNA dramatically stimulates the rate of RNase E phase separation in vitro, explaining the dissolution of BR-bodies after cellular mRNA depletion observed previously. Altogether, these results suggest that a complex network of protein-protein and protein-RNA interactions controls BR-body phase separation and RNA processing.
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Affiliation(s)
- V Nandana
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - I W Rathnayaka-Mudiyanselage
- Wayne State University, Department of Biological Sciences, Detroit, MI
- Wayne State University, Department of Chemistry, Detroit, MI
| | - N S Muthunayak
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - A Hatami
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - C B Mousseau
- University of Notre Dame, Department of Chemistry, Notre Dame, IN
| | | | - J Vaishnav
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - M Collins
- University of Pittsburgh, Department of Chemistry, Pittsburgh, PA
| | - A Gega
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | | | - H Yassine
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - A Ghosh
- Wayne State University, Department of Biological Sciences, Detroit, MI
| | - J S Biteen
- University of Michigan, Department of Chemistry, Ann Arbor, MI
| | - Y Zhu
- Wayne State University, Department of Chemical Engineering and Materials Science, Detroit, MI
| | - M M Champion
- University of Notre Dame, Department of Chemistry, Notre Dame, IN
| | - W S Childers
- University of Pittsburgh, Department of Chemistry, Pittsburgh, PA
| | - J M Schrader
- Wayne State University, Department of Biological Sciences, Detroit, MI
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4
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Lu N, Duvall SW, Zhao G, Kowallis KA, Zhang C, Tan W, Sun J, Petitjean HN, Tomares DT, Zhao GP, Childers WS, Zhao W. Scaffold-Scaffold Interaction Facilitates Cell Polarity Development in Caulobacter crescentus. mBio 2023; 14:e0321822. [PMID: 36971555 PMCID: PMC10127582 DOI: 10.1128/mbio.03218-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/29/2023] Open
Abstract
Caulobacter crescentus
is a well-established bacterial model to study asymmetric cell division for decades. During cell development, the polarization of scaffold protein PopZ from monopolar to bipolar plays a central role in
C. crescentus
asymmetric cell division.
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5
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Synchronized Swarmers and Sticky Stalks: Caulobacter crescentus as a Model for Bacterial Cell Biology. J Bacteriol 2023; 205:e0038422. [PMID: 36715542 PMCID: PMC9945503 DOI: 10.1128/jb.00384-22] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
First isolated and classified in the 1960s, Caulobacter crescentus has been instrumental in the study of bacterial cell biology and differentiation. C. crescentus is a Gram-negative alphaproteobacterium that exhibits a dimorphic life cycle composed of two distinct cell types: a motile swarmer cell and a nonmotile, division-competent stalked cell. Progression through the cell cycle is accentuated by tightly controlled biogenesis of appendages, morphological transitions, and distinct localization of developmental regulators. These features as well as the ability to synchronize populations of cells and follow their progression make C. crescentus an ideal model for answering questions relevant to how development and differentiation are achieved at the single-cell level. This review will explore the discovery and development of C. crescentus as a model organism before diving into several key features and discoveries that have made it such a powerful organism to study. Finally, we will summarize a few of the ongoing areas of research that are leveraging knowledge gained over the last century with C. crescentus to highlight its continuing role at the forefront of cell and developmental biology.
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6
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Kaplan M, Chreifi G, Metskas LA, Liedtke J, Wood CR, Oikonomou CM, Nicolas WJ, Subramanian P, Zacharoff LA, Wang Y, Chang YW, Beeby M, Dobro MJ, Zhu Y, McBride MJ, Briegel A, Shaffer CL, Jensen GJ. In situ imaging of bacterial outer membrane projections and associated protein complexes using electron cryo-tomography. eLife 2021; 10:73099. [PMID: 34468314 PMCID: PMC8455137 DOI: 10.7554/elife.73099] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 08/23/2021] [Indexed: 12/19/2022] Open
Abstract
The ability to produce outer membrane projections in the form of tubular membrane extensions (MEs) and membrane vesicles (MVs) is a widespread phenomenon among diderm bacteria. Despite this, our knowledge of the ultrastructure of these extensions and their associated protein complexes remains limited. Here, we surveyed the ultrastructure and formation of MEs and MVs, and their associated protein complexes, in tens of thousands of electron cryo-tomograms of ~90 bacterial species that we have collected for various projects over the past 15 years (Jensen lab database), in addition to data generated in the Briegel lab. We identified outer MEs and MVs in 13 diderm bacterial species and classified several major ultrastructures: (1) tubes with a uniform diameter (with or without an internal scaffold), (2) tubes with irregular diameter, (3) tubes with a vesicular dilation at their tip, (4) pearling tubes, (5) connected chains of vesicles (with or without neck-like connectors), (6) budding vesicles and nanopods. We also identified several protein complexes associated with these MEs and MVs which were distributed either randomly or exclusively at the tip. These complexes include a secretin-like structure and a novel crown-shaped structure observed primarily in vesicles from lysed cells. In total, this work helps to characterize the diversity of bacterial membrane projections and lays the groundwork for future research in this field.
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Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Georges Chreifi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Lauren Ann Metskas
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Janine Liedtke
- Leiden University, Sylvius Laboratories, Leiden, Netherlands
| | - Cecily R Wood
- Department of Veterinary Science, University of Kentucky, Lexington, United States
| | - Catherine M Oikonomou
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - William J Nicolas
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Poorna Subramanian
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Lori A Zacharoff
- Department of Physics and Astronomy, University of Southern California, Los Angeles, United States
| | - Yuhang Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States
| | - Yi-Wei Chang
- Department of Biochemistry and Biophysics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, United States
| | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, United Kingdom
| | | | - Yongtao Zhu
- Department of Biological Sciences, Minnesota State University, Mankato, United States
| | - Mark J McBride
- Department of Biological Sciences, University of Wisconsin-Milwaukee, Milwaukee, United States
| | - Ariane Briegel
- Leiden University, Sylvius Laboratories, Leiden, Netherlands
| | - Carrie L Shaffer
- Department of Veterinary Science, University of Kentucky, Lexington, United States.,Department of Microbiology, Immunology, and Molecular Genetics, University of Kentucky, Lexington, United States.,Department of Pharmaceutical Sciences, University of Kentucky, Lexington, United States
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, United States.,Department of Chemistry and Biochemistry, Brigham Young University, Provo, United States
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7
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Kaplan M, Wang Y, Chreifi G, Zhang L, Chang YW, Jensen GJ. Programmed Flagellar Ejection in Caulobacter crescentus Leaves PL-subcomplexes. J Mol Biol 2021; 433:167004. [PMID: 33891903 PMCID: PMC9843737 DOI: 10.1016/j.jmb.2021.167004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 04/12/2021] [Accepted: 04/13/2021] [Indexed: 01/19/2023]
Abstract
The bacterial flagellum consists of a long extracellular filament that is rotated by a motor embedded in the cell envelope. While flagellar assembly has been extensively studied,1 the disassembly process remains less well understood. In addition to the programmed flagellar ejection that occurs during the life cycle of Caulobacter crescentus, we and others have recently shown that many bacterial species lose their flagella under starvation conditions, leaving relic structures in the outer membrane.2-7 However, it remains unknown whether the programmed flagellar ejection of C. crescentus leaves similar relics or not. Here, we imaged the various stages of the C. crescentus life cycle using electron cryo-tomography (cryo-ET) and found that flagellar relic subcomplexes, akin to those produced in the starvation-induced process, remain as a result of flagellar ejection during cell development. This similarity suggests that the programmed flagellar ejection of C. crescentus might share a common evolutionary path with the more general, and likely more ancient,3 starvation-related flagellar loss.
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Affiliation(s)
- Mohammed Kaplan
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Yuhang Wang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Georges Chreifi
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Lujia Zhang
- Shanghai Engineering Research Center of Molecular Therapeutics and New Drug Development, School of Chemistry and Molecular Engineering, East China Normal University, Shanghai 200062, China; New York University-East China Normal University Center for Computational Chemistry, New York University Shanghai, Shanghai 200062, China
| | - Yi-Wei Chang
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA
| | - Grant J Jensen
- Division of Biology and Biological Engineering, California Institute of Technology, Pasadena, CA 91125, USA; Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84604, USA.
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8
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Joseph AM, Daw S, Sadhir I, Badrinarayanan A. Coordination between nucleotide excision repair and specialized polymerase DnaE2 action enables DNA damage survival in non-replicating bacteria. eLife 2021; 10:e67552. [PMID: 33856342 PMCID: PMC8102061 DOI: 10.7554/elife.67552] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2021] [Accepted: 04/14/2021] [Indexed: 12/15/2022] Open
Abstract
Translesion synthesis (TLS) is a highly conserved mutagenic DNA lesion tolerance pathway, which employs specialized, low-fidelity DNA polymerases to synthesize across lesions. Current models suggest that activity of these polymerases is predominantly associated with ongoing replication, functioning either at or behind the replication fork. Here we provide evidence for DNA damage-dependent function of a specialized polymerase, DnaE2, in replication-independent conditions. We develop an assay to follow lesion repair in non-replicating Caulobacter and observe that components of the replication machinery localize on DNA in response to damage. These localizations persist in the absence of DnaE2 or if catalytic activity of this polymerase is mutated. Single-stranded DNA gaps for SSB binding and low-fidelity polymerase-mediated synthesis are generated by nucleotide excision repair (NER), as replisome components fail to localize in the absence of NER. This mechanism of gap-filling facilitates cell cycle restoration when cells are released into replication-permissive conditions. Thus, such cross-talk (between activity of NER and specialized polymerases in subsequent gap-filling) helps preserve genome integrity and enhances survival in a replication-independent manner.
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Affiliation(s)
- Asha Mary Joseph
- National Centre for Biological Sciences - Tata Institute of Fundamental ResearchBangaloreIndia
| | - Saheli Daw
- National Centre for Biological Sciences - Tata Institute of Fundamental ResearchBangaloreIndia
| | - Ismath Sadhir
- National Centre for Biological Sciences - Tata Institute of Fundamental ResearchBangaloreIndia
- Max Planck Institute for Terrestrial Microbiology, LOEWE Centre for Synthetic Microbiology (SYNMIKRO)MarburgGermany
| | - Anjana Badrinarayanan
- National Centre for Biological Sciences - Tata Institute of Fundamental ResearchBangaloreIndia
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9
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A localized adaptor protein performs distinct functions at the Caulobacter cell poles. Proc Natl Acad Sci U S A 2021; 118:2024705118. [PMID: 33753507 PMCID: PMC8020655 DOI: 10.1073/pnas.2024705118] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
Asymmetric cell division yields two distinct daughter cells by mechanisms that underlie stem cell behavior and cellular diversity in all organisms. The bacterium Caulobacter crescentus is able to orchestrate this complex process with less than 4,000 genes. This article describes a strategy deployed by Caulobacter where a regulatory protein, PopA, is programed to perform distinct roles based on its subcellular address. We demonstrate that, depending on the availability of a second messenger molecule, PopA adopts either a monomer or dimer form. The two oligomeric forms interact with different partners at the two cell poles, playing a critical role in the degradation of a master transcription factor at one pole and flagellar assembly at the other pole. Asymmetric cell division generates two daughter cells with distinct characteristics and fates. Positioning different regulatory and signaling proteins at the opposing ends of the predivisional cell produces molecularly distinct daughter cells. Here, we report a strategy deployed by the asymmetrically dividing bacterium Caulobacter crescentus where a regulatory protein is programmed to perform distinct functions at the opposing cell poles. We find that the CtrA proteolysis adaptor protein PopA assumes distinct oligomeric states at the two cell poles through asymmetrically distributed c-di-GMP: dimeric at the stalked pole and monomeric at the swarmer pole. Different polar organizing proteins at each cell pole recruit PopA where it interacts with and mediates the function of two molecular machines: the ClpXP degradation machinery at the stalked pole and the flagellar basal body at the swarmer pole. We discovered a binding partner of PopA at the swarmer cell pole that together with PopA regulates the length of the flagella filament. Our work demonstrates how a second messenger provides spatiotemporal cues to change the physical behavior of an effector protein, thereby facilitating asymmetry.
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10
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Duvall SW, Childers WS. Design of a Histidine Kinase FRET Sensor to Detect Complex Signal Integration within Living Bacteria. ACS Sens 2020; 5:1589-1596. [PMID: 32495620 DOI: 10.1021/acssensors.0c00008] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Histidine kinases (HK) switch between conformational states that promote kinase and phosphatase activities to regulate diverse cellular processes. Past studies have shown that these functional states can display heterogeneity between cells in microbial communities and can vary at the subcellular level. Methods to track and correlate the kinase conformational state with the phenotypic response of living bacteria cells will offer new opportunities to interrogate bacterial signaling mechanisms. As a proof of principle, we incorporated both mClover3 (donor) and mRuby3 (acceptor) fluorescent proteins into the Caulobacter crescentus cell-cycle HK CckA as an in vivo fluorescence resonance energy transfer (FRET) sensor to detect these structural changes. Our engineered FRET sensor was responsive to CckA-specific input signals and detected subcellular changes in CckA signal integration that occurs as cells develop. We demonstrated the potential of using the CckA FRET sensor as an in vivo screening tool for HK inhibitors. In summary, we have developed a new HK FRET sensor design strategy that can be adopted to monitor in vivo changes for interrogation of a broad range of signaling mechanisms in living bacteria.
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Affiliation(s)
- Samuel W. Duvall
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - W. Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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11
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Al-Husini N, Tomares DT, Pfaffenberger ZJ, Muthunayake NS, Samad MA, Zuo T, Bitar O, Aretakis JR, Bharmal MHM, Gega A, Biteen JS, Childers WS, Schrader JM. BR-Bodies Provide Selectively Permeable Condensates that Stimulate mRNA Decay and Prevent Release of Decay Intermediates. Mol Cell 2020; 78:670-682.e8. [PMID: 32343944 DOI: 10.1016/j.molcel.2020.04.001] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2019] [Revised: 12/16/2019] [Accepted: 03/30/2020] [Indexed: 12/22/2022]
Abstract
Biomolecular condensates play a key role in organizing RNAs and proteins into membraneless organelles. Bacterial RNP-bodies (BR-bodies) are a biomolecular condensate containing the RNA degradosome mRNA decay machinery, but the biochemical function of such organization remains poorly defined. Here, we define the RNA substrates of BR-bodies through enrichment of the bodies followed by RNA sequencing (RNA-seq). We find that long, poorly translated mRNAs, small RNAs, and antisense RNAs are the main substrates, while rRNA, tRNA, and other conserved non-coding RNAs (ncRNAs) are excluded from these bodies. BR-bodies stimulate the mRNA decay rate of enriched mRNAs, helping to reshape the cellular mRNA pool. We also observe that BR-body formation promotes complete mRNA decay, avoiding the buildup of toxic endo-cleaved mRNA decay intermediates. The combined selective permeability of BR-bodies for both enzymes and substrates together with the stimulation of the sub-steps of mRNA decay provide an effective organization strategy for bacterial mRNA decay.
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Affiliation(s)
- Nadra Al-Husini
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA
| | | | | | - Mohammad A Samad
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Tiancheng Zuo
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - Obaidah Bitar
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - James R Aretakis
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | | | - Alisa Gega
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA
| | - Julie S Biteen
- Department of Chemistry, University of Michigan, Ann Arbor, MI 48109, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, USA.
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI 48202, USA.
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12
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Abstract
Structural maintenance of chromosomes (SMC) proteins play a central role in the organization, segregation and maintenance of chromosomes across domains of life. In bacteria, an SMC-family protein, RecN, has been implicated to have important functions in DNA damage repair. Recent studies have suggested that RecN is required to increase chromosome cohesion in response to DNA damage and may also stimulate specific events during recombination-based repair. While biochemical and genetic assays provide insights into mechanism of action of RecN and other repair factors, in vivo understanding of activity and regulation of proteins can be predominantly gained via microscopy-based approaches. Here, we describe a protocol to study the localization of fluorescently tagged RecN to a site-specific double-strand break (DSB) in Caulobacter crescentus. We further outline a method to probe RecN dynamics in cells with a single, nonreplicating chromosome. This technique can be used to study the early steps of recombination-based repair and understand the regulation of protein recruitment to and further association with sites of damage.
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13
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Lasker K, von Diezmann L, Zhou X, Ahrens DG, Mann TH, Moerner WE, Shapiro L. Selective sequestration of signalling proteins in a membraneless organelle reinforces the spatial regulation of asymmetry in Caulobacter crescentus. Nat Microbiol 2020; 5:418-429. [PMID: 31959967 PMCID: PMC7549192 DOI: 10.1038/s41564-019-0647-7] [Citation(s) in RCA: 68] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/25/2019] [Indexed: 12/16/2022]
Abstract
Selective recruitment and concentration of signalling proteins within membraneless compartments is a ubiquitous mechanism for subcellular organization1-3. The dynamic flow of molecules into and out of these compartments occurs on faster timescales than for membrane-enclosed organelles, presenting a possible mechanism to control spatial patterning within cells. Here, we combine single-molecule tracking and super-resolution microscopy, light-induced subcellular localization, reaction-diffusion modelling and a spatially resolved promoter activation assay to study signal exchange in and out of the 200 nm cytoplasmic pole-organizing protein popZ (PopZ) microdomain at the cell pole of the asymmetrically dividing bacterium Caulobacter crescentus4-8. Two phospho-signalling proteins, the transmembrane histidine kinase CckA and the cytoplasmic phosphotransferase ChpT, provide the only phosphate source for the cell fate-determining transcription factor CtrA9-18. We find that all three proteins exhibit restricted rates of entry into and escape from the microdomain as well as enhanced phospho-signalling within, leading to a submicron gradient of activated CtrA-P19 that is stable and sublinear. Entry into the microdomain is selective for cytosolic proteins and requires a binding pathway to PopZ. Our work demonstrates how nanoscale protein assemblies can modulate signal propagation with fine spatial resolution, and that in Caulobacter, this modulation serves to reinforce asymmetry and differential cell fate of the two daughter cells.
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Affiliation(s)
- Keren Lasker
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Lexy von Diezmann
- Department of Chemistry, Stanford University, Stanford, CA, USA
- Center for Cell and Genome Science, University of Utah, Salt Lake City, UT, USA
- School of Biological Sciences, University of Utah, Salt Lake City, UT, USA
| | - Xiaofeng Zhou
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Daniel G Ahrens
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
| | - Thomas H Mann
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA
- NOMIS Center for Immunobiology and Microbial Pathogenesis, Salk Institute for Biological Studies, La Jolla, CA, USA
| | - W E Moerner
- Department of Chemistry, Stanford University, Stanford, CA, USA
| | - Lucy Shapiro
- Department of Developmental Biology, Stanford University School of Medicine, Stanford, CA, USA.
- Chan Zuckerberg Biohub, San Francisco, CA, USA.
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14
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Role of Caulobacter Cell Surface Structures in Colonization of the Air-Liquid Interface. J Bacteriol 2019; 201:JB.00064-19. [PMID: 31010900 DOI: 10.1128/jb.00064-19] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Accepted: 04/15/2019] [Indexed: 01/17/2023] Open
Abstract
In aquatic environments, Caulobacter spp. can be found at the boundary between liquid and air known as the neuston. I report an approach to study temporal features of Caulobacter crescentus colonization and pellicle biofilm development at the air-liquid interface and have defined the role of cell surface structures in this process. At this interface, C. crescentus initially forms a monolayer of cells bearing a surface adhesin known as the holdfast. When excised from the liquid surface, this monolayer strongly adheres to glass. The monolayer subsequently develops into a three-dimensional structure that is highly enriched in clusters of stalked cells known as rosettes. As this pellicle film matures, it becomes more cohesive and less adherent to a glass surface. A mutant strain lacking a flagellum does not efficiently reach the surface, and strains lacking type IV pili exhibit defects in organization of the three-dimensional pellicle. Strains unable to synthesize the holdfast fail to accumulate at the boundary between air and liquid and do not form a pellicle. Phase-contrast images support a model whereby the holdfast functions to trap C. crescentus cells at the air-liquid boundary. Unlike the holdfast, neither the flagellum nor type IV pili are required for C. crescentus to partition to the air-liquid interface. While it is well established that the holdfast enables adherence to solid surfaces, this study provides evidence that the holdfast has physicochemical properties that allow partitioning of nonmotile mother cells to the air-liquid interface and facilitate colonization of this microenvironment.IMPORTANCE In aquatic environments, the boundary at the air interface is often highly enriched with nutrients and oxygen. Colonization of this niche likely confers a significant fitness advantage in many cases. This study provides evidence that the cell surface adhesin known as a holdfast enables Caulobacter crescentus to partition to and colonize the air-liquid interface. Additional surface structures, including the flagellum and type IV pili, are important determinants of colonization and biofilm formation at this boundary. Considering that holdfast-like adhesins are broadly conserved in Caulobacter spp. and other members of the diverse class Alphaproteobacteria, these surface structures may function broadly to facilitate colonization of air-liquid boundaries in a range of ecological contexts, including freshwater, marine, and soil ecosystems.
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15
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Absolute Measurements of mRNA Translation in Caulobacter crescentus Reveal Important Fitness Costs of Vitamin B 12 Scavenging. mSystems 2019; 4:4/4/e00170-19. [PMID: 31138672 PMCID: PMC6538847 DOI: 10.1128/msystems.00170-19] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Caulobacter crescentus is a model system of the bacterial cell cycle culminating in asymmetric cell division, with each daughter cell inheriting a distinct set of proteins. While a genetic network of master transcription factors coordinates the cell cycle timing of transcription for nearly 20% of Caulobacter genes, we lack knowledge of how many of each protein “part” encoded in the genome are synthesized. Therefore, to determine the absolute production rates across the genome, we performed ribosome profiling, providing, for the first time, a quantitative resource with measurements of each protein “part” needed to generate daughter cells. This resource furthers the goal of a systems-level understanding of the genetic network controlling asymmetric cell division. To highlight the utility of this data set, we probe the protein synthesis cost of a B12 utilization pathway and provide new insights into Caulobacter’s adaptation to its natural environments. Caulobacter crescentus is a model for the bacterial cell cycle which culminates in asymmetric cell division, yet little is known about the absolute levels of protein synthesis of the cellular parts needed to complete the cell cycle. Here we utilize ribosome profiling to provide absolute measurements of mRNA translation in C. crescentus, providing an important resource with quantitative genome-wide measurements of protein output across individual genes. Analysis of protein synthesis rates revealed ∼4.5% of cellular protein synthesis is for genes related to vitamin B12 import (btuB) and B12-independent methionine biosynthesis (metE) when grown in common growth media lacking B12. While its facultative B12 lifestyle provides a fitness advantage in the absence of B12, we find that it provides a fitness disadvantage of the cells in the presence of B12, potentially explaining why many Caulobacter species have lost the metE gene and become obligates for B12. IMPORTANCECaulobacter crescentus is a model system of the bacterial cell cycle culminating in asymmetric cell division, with each daughter cell inheriting a distinct set of proteins. While a genetic network of master transcription factors coordinates the cell cycle timing of transcription for nearly 20% of Caulobacter genes, we lack knowledge of how many of each protein “part” encoded in the genome are synthesized. Therefore, to determine the absolute production rates across the genome, we performed ribosome profiling, providing, for the first time, a quantitative resource with measurements of each protein “part” needed to generate daughter cells. This resource furthers the goal of a systems-level understanding of the genetic network controlling asymmetric cell division. To highlight the utility of this data set, we probe the protein synthesis cost of a B12 utilization pathway and provide new insights into Caulobacter’s adaptation to its natural environments. Author Video: An author video summary of this article is available.
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16
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Importance of Pyruvate Sensing and Transport for the Resuscitation of Viable but Nonculturable Escherichia coli K-12. J Bacteriol 2019; 201:JB.00610-18. [PMID: 30420452 DOI: 10.1128/jb.00610-18] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 10/29/2018] [Indexed: 12/21/2022] Open
Abstract
Escherichia coli and many other bacterial species can enter into a viable but nonculturable (VBNC) state, which is a survival strategy adopted by cells exposed to adverse environmental conditions. Pyruvate is known to be one factor that promotes resuscitation of VBNC cells. Here we studied the role of a pyruvate-sensing network, composed of the histidine kinase-response regulator systems BtsS/BtsR and YpdA/YpdB and the target gene btsT, encoding the high-affinity pyruvate/H+ symporter BtsT, in the resuscitation of VBNC E. coli K-12 cells after exposure to cold for 120 days. Analysis of the proteome of VBNC cells revealed upregulation, relative to exponentially growing cells, of BtsT and other proteins involved in pyruvate metabolism. Provision of pyruvate stimulated protein and DNA biosynthesis, and thus resuscitation, in wild-type but not btsSR ypdAB mutant VBNC cells. This result was corroborated by time-dependent tracking of the resuscitation of individual VBNC E. coli cells observed in a microfluidic system. Finally, transport assays revealed that 14C-labeled pyruvate was rapidly taken up into VBNC cells by BtsT. These results provide the first evidence that pyruvate is taken up as a carbon source for the resuscitation of VBNC E. coli cells.IMPORTANCE Viable but nonculturable (VBNC) bacteria do not form colonies in standard medium but otherwise retain their metabolic activity and can express toxic proteins. Many bacterial genera, including Escherichia, Vibrio, and Listeria, have been shown to enter the VBNC state upon exposure to adverse conditions, such as low temperature, radiation, and starvation. Ultimately, these organisms pose a public health risk with potential implications for the pharmaceutical and food industries, as dormant organisms are especially difficult to selectively eliminate and VBNC bacteria can be resuscitated if placed in an environment with appropriate nutrition and temperature. Here we used a microfluidic system to monitor the resuscitation of single VBNC cells over time. We provide new molecular insights into the initiation of resuscitation by demonstrating that VBNC E. coli cells rapidly take up pyruvate with an inducible high-affinity transporter, whose expression is triggered by the BtsSR-YpdAB sensing network.
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17
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Le TBK. Chromosome Conformation Capture with Deep Sequencing to Study the Roles of the Structural Maintenance of Chromosomes Complex In Vivo. Methods Mol Biol 2019; 2004:105-118. [PMID: 31147913 DOI: 10.1007/978-1-4939-9520-2_9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Recent applications of chromosome conformation capture with deep sequencing (Hi-C and other C techniques) has enabled high-throughput investigations and driven major advances in understanding chromosome organization in bacteria and eukaryotes. C techniques reveal systematically the identities of interacting DNA and the frequency of each interaction in vivo. Beyond a bird's-eye view survey of the global chromosome architecture, C techniques together with genetic perturbation have proven to be powerful in understanding factors that shape chromosome architectures. The structural maintenance of chromosomes (SMC) proteins play major roles in organizing the chromosomes from bacteria to humans, and C techniques have contributed to understanding their mechanism and impact on genome organization in a cellular context. Here, I describe a Hi-C protocol, a variant of C techniques, to construct genome-wide DNA contact maps for bacteria. This protocol is optimized for the gram-negative bacterium Caulobacter crescentus, but it can be readily adapted for any bacterial species of interest.
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Affiliation(s)
- Tung B K Le
- Department of Molecular Microbiology, John Innes Centre, Norwich, UK.
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18
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Al-Husini N, Tomares DT, Bitar O, Childers WS, Schrader JM. α-Proteobacterial RNA Degradosomes Assemble Liquid-Liquid Phase-Separated RNP Bodies. Mol Cell 2018; 71:1027-1039.e14. [PMID: 30197298 DOI: 10.1016/j.molcel.2018.08.003] [Citation(s) in RCA: 117] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2018] [Revised: 06/11/2018] [Accepted: 07/31/2018] [Indexed: 12/30/2022]
Abstract
Ribonucleoprotein (RNP) granules play an important role in organizing eukaryotic mRNA metabolism via liquid-liquid phase separation (LLPS) of mRNA decay factors into membrane-less organelles in the cytoplasm. Here we show that the bacterium Caulobacter crescentus Ribonuclease (RNase) E assembles RNP LLPS condensates that we term bacterial RNP-bodies (BR-bodies), similar to eukaryotic P-bodies and stress granules. RNase E requires RNA to assemble a BR-body, and disassembly requires RNA cleavage, suggesting BR-bodies provide localized sites of RNA degradation. The unstructured C-terminal domain of RNase E is both necessary and sufficient to assemble the core of the BR-body, is functionally conserved in related α-proteobacteria, and influences mRNA degradation. BR-bodies are rapidly induced under cellular stresses and provide enhanced cell growth under stress. To our knowledge, Caulobacter RNase E is the first bacterial protein identified that forms LLPS condensates, providing an effective strategy for subcellular organization in cells lacking membrane-bound compartments.
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Affiliation(s)
- Nadra Al-Husini
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
| | - Dylan T Tomares
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA
| | - Obaidah Bitar
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA
| | - W Seth Childers
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA, 15260, USA.
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI, 48202, USA.
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19
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Aretakis JR, Al-Husini N, Schrader JM. Methodology for Ribosome Profiling of Key Stages of the Caulobacter crescentus Cell Cycle. Methods Enzymol 2018; 612:443-465. [PMID: 30502952 DOI: 10.1016/bs.mie.2018.07.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Bacterial cell division is the result of a productive round of the cell cycle to yield two daughter cells. The cell cycle is highly coordinated in Caulobacter crescentus where it is driven by a cell cycle gene-regulatory network that coordinates gene expression with the major cell cycle events such as chromosome replication and cell division. Recent ribosomes profiling data showed that 484 genes undergo changes in translation efficiency during the cell cycle, suggesting a broad role for translational control in cell cycle regulation. In this chapter, we focus on how to perform ribosome profiling to measure the translation efficiency across cellular mRNAs at key stages in the Caulobacter cell cycle. This methodology relies on the high-yield ludox gradient synchronization of Caulobacter cells followed by ribosome profiling to measure ribosome density and total RNA-seq to measure mRNA levels.
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Affiliation(s)
- James R Aretakis
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Nadra Al-Husini
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States
| | - Jared M Schrader
- Department of Biological Sciences, Wayne State University, Detroit, MI, United States.
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20
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Beroual W, Brilli M, Biondi EG. Non-coding RNAs Potentially Controlling Cell Cycle in the Model Caulobacter crescentus: A Bioinformatic Approach. Front Genet 2018; 9:164. [PMID: 29899753 PMCID: PMC5988900 DOI: 10.3389/fgene.2018.00164] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 04/23/2018] [Indexed: 11/13/2022] Open
Abstract
Caulobacter crescentus represents a remarkable model system to investigate global regulatory programs in bacteria. In particular, several decades of intensive study have revealed that its cell cycle is controlled by a cascade of master regulators, such as DnaA, GcrA, CcrM, and CtrA, that are responsible for the activation of functions required to progress through DNA replication, cell division and morphogenesis of polar structures (flagellum and stalk). In order to accomplish this task, several post-translational (phosphorylation and proteolysis) and transcriptional mechanisms are involved. Surprisingly, the role of non-coding RNAs (ncRNAs) in regulating the cell cycle has not been investigated. Here we describe a bioinformatic analysis that revealed that ncRNAs may well play a crucial role regulating cell cycle in C. crescentus. We used available prediction tools to understand which target genes may be regulated by ncRNAs in this bacterium. Furthermore, we predicted whether ncRNAs with a cell cycle regulated expression profile may be directly regulated by DnaA, GcrA, and CtrA, at the onset, during or end of the S-phase/swarmer cell, or if any of them has CcrM methylation sites in the promoter region. Our analysis suggests the existence of a potentially very important network of ncRNAs regulated by or regulating well-known cell cycle genes in C. crescentus. Our hypothesis is that ncRNAs are intimately connected to the known regulatory network, playing a crucial modulatory role in cell cycle progression.
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Affiliation(s)
- Wanassa Beroual
- Laboratoire de Chimie Bactérienne, Centre National de la Recherche Scientifique, Aix Marseille University, Marseille, France
| | - Matteo Brilli
- Department of Biosciences, Pediatric Clinical Research Center "Romeo ed Enrica Invernizzi, " University of Milan, Milan, Italy
| | - Emanuele G Biondi
- Laboratoire de Chimie Bactérienne, Centre National de la Recherche Scientifique, Aix Marseille University, Marseille, France
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21
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Kemter FS, Messerschmidt SJ, Schallopp N, Sobetzko P, Lang E, Bunk B, Spröer C, Teschler JK, Yildiz FH, Overmann J, Waldminghaus T. Synchronous termination of replication of the two chromosomes is an evolutionary selected feature in Vibrionaceae. PLoS Genet 2018; 14:e1007251. [PMID: 29505558 PMCID: PMC5854411 DOI: 10.1371/journal.pgen.1007251] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Revised: 03/15/2018] [Accepted: 02/13/2018] [Indexed: 11/18/2022] Open
Abstract
Vibrio cholerae, the causative agent of the cholera disease, is commonly used as a model organism for the study of bacteria with multipartite genomes. Its two chromosomes of different sizes initiate their DNA replication at distinct time points in the cell cycle and terminate in synchrony. In this study, the time-delayed start of Chr2 was verified in a synchronized cell population. This replication pattern suggests two possible regulation mechanisms for other Vibrio species with different sized secondary chromosomes: Either all Chr2 start DNA replication with a fixed delay after Chr1 initiation, or the timepoint at which Chr2 initiates varies such that termination of chromosomal replication occurs in synchrony. We investigated these two models and revealed that the two chromosomes of various Vibrionaceae species terminate in synchrony while Chr2-initiation timing relative to Chr1 is variable. Moreover, the sequence and function of the Chr2-triggering crtS site recently discovered in V. cholerae were found to be conserved, explaining the observed timing mechanism. Our results suggest that it is beneficial for bacterial cells with multiple chromosomes to synchronize their replication termination, potentially to optimize chromosome related processes as dimer resolution or segregation.
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Affiliation(s)
- Franziska S. Kemter
- LOEWE Center for Synthetic Microbiology–SYNMIKRO, Philipps-Universität Marburg, Marburg, Germany
| | - Sonja J. Messerschmidt
- LOEWE Center for Synthetic Microbiology–SYNMIKRO, Philipps-Universität Marburg, Marburg, Germany
| | - Nadine Schallopp
- LOEWE Center for Synthetic Microbiology–SYNMIKRO, Philipps-Universität Marburg, Marburg, Germany
| | - Patrick Sobetzko
- LOEWE Center for Synthetic Microbiology–SYNMIKRO, Philipps-Universität Marburg, Marburg, Germany
| | - Elke Lang
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Boyke Bunk
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Cathrin Spröer
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
| | - Jennifer K. Teschler
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, United States of America
| | - Fitnat H. Yildiz
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, Santa Cruz, United States of America
| | - Jörg Overmann
- Leibniz Institute DSMZ-German Collection of Microorganisms and Cell Cultures, Braunschweig, Germany
- German Centre of Infection Research (DZIF), Partner Site Hannover–Braunschweig, Braunschweig, Germany
| | - Torsten Waldminghaus
- LOEWE Center for Synthetic Microbiology–SYNMIKRO, Philipps-Universität Marburg, Marburg, Germany
- * E-mail:
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22
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Felletti M, Omnus DJ, Jonas K. Regulation of the replication initiator DnaA in Caulobacter crescentus. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1862:697-705. [PMID: 29382570 DOI: 10.1016/j.bbagrm.2018.01.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/28/2017] [Accepted: 01/10/2018] [Indexed: 11/18/2022]
Abstract
The decision to initiate DNA replication is a critical step in the cell cycle of all organisms. In nearly all bacteria, replication initiation requires the activity of the conserved replication initiation protein DnaA. Due to its central role in cell cycle progression, DnaA activity must be precisely regulated. This review summarizes the current state of DnaA regulation in the asymmetrically dividing α-proteobacterium Caulobacter crescentus, an important model for bacterial cell cycle studies. Mechanisms will be discussed that regulate DnaA activity and abundance under optimal conditions and in coordination with the asymmetric Caulobacter cell cycle. Furthermore, we highlight recent findings of how regulated DnaA synthesis and degradation collaborate to adjust DnaA abundance under stress conditions. The mechanisms described provide important examples of how DNA replication is regulated in an α-proteobacterium and thus represent an important starting point for the study of DNA replication in many other bacteria. This article is part of a Special Issue entitled: Dynamic gene expression, edited by Prof. Patrick Viollier.
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Affiliation(s)
- Michele Felletti
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Deike J Omnus
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden
| | - Kristina Jonas
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, 10691 Stockholm, Sweden.
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23
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A New Essential Cell Division Protein in Caulobacter crescentus. J Bacteriol 2017; 199:JB.00811-16. [PMID: 28167520 DOI: 10.1128/jb.00811-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2016] [Accepted: 01/31/2017] [Indexed: 11/20/2022] Open
Abstract
Bacterial cell division is a complex process that relies on a multiprotein complex composed of a core of widely conserved and generally essential proteins and on accessory proteins that vary in number and identity in different bacteria. The assembly of this complex and, particularly, the initiation of constriction are regulated processes that have come under intensive study. In this work, we characterize the function of DipI, a protein conserved in Alphaproteobacteria and Betaproteobacteria that is essential in Caulobacter crescentus Our results show that DipI is a periplasmic protein that is recruited late to the division site and that it is required for the initiation of constriction. The recruitment of the conserved cell division proteins is not affected by the absence of DipI, but localization of DipI to the division site occurs only after a mature divisome has formed. Yeast two-hybrid analysis showed that DipI strongly interacts with the FtsQLB complex, which has been recently implicated in regulating constriction initiation. A possible role of DipI in this process is discussed.IMPORTANCE Bacterial cell division is a complex process for which most bacterial cells assemble a multiprotein complex that consists of conserved proteins and of accessory proteins that differ among bacterial groups. In this work, we describe a new cell division protein (DipI) present only in a group of bacteria but essential in Caulobacter crescentus Cells devoid of DipI cannot constrict. Although a mature divisome is required for DipI recruitment, DipI is not needed for recruiting other division proteins. These results, together with the interaction of DipI with a protein complex that has been suggested to regulate cell wall synthesis during division, suggest that DipI may be part of the regulatory mechanism that controls constriction initiation.
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24
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Hallez R, Delaby M, Sanselicio S, Viollier PH. Hit the right spots: cell cycle control by phosphorylated guanosines in alphaproteobacteria. Nat Rev Microbiol 2017; 15:137-148. [PMID: 28138140 DOI: 10.1038/nrmicro.2016.183] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
The class Alphaproteobacteria includes Gram-negative free-living, symbiotic and obligate intracellular bacteria, as well as important plant, animal and human pathogens. Recent work has established the key antagonistic roles that phosphorylated guanosines, cyclic-di-GMP (c-di-GMP) and the alarmones guanosine tetraphosphate and guanosine pentaphosphate (collectively referred to as (p)ppGpp), have in the regulation of the cell cycle in these bacteria. In this Review, we discuss the insights that have been gained into the regulation of the initiation of DNA replication and cytokinesis by these second messengers, with a particular focus on the cell cycle of Caulobacter crescentus. We explore how the fluctuating levels of c-di-GMP and (p)ppGpp during the progression of the cell cycle and under conditions of stress control the synthesis and proteolysis of key regulators of the cell cycle. As these signals also promote bacterial interactions with host cells, the enzymes that control (p)ppGpp and c-di-GMP are attractive antibacterial targets.
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Affiliation(s)
- Régis Hallez
- Bacterial Cell cycle and Development (BCcD), Unité de recherche en biologie des micro-organismes (URBM), University of Namur, 61 Rue de Bruxelles, Namur 5000, Belgium
| | - Marie Delaby
- Department of Microbiology and Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
| | - Stefano Sanselicio
- Department of Microbiology and Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland.,Present address: Molecular Genetics Group, Groningen Biomolecular Sciences and Biotechnology Institute, Centre for Synthetic Biology, University of Groningen, Nijenborgh 7, 9747 AG Groningen, The Netherlands
| | - Patrick H Viollier
- Department of Microbiology and Molecular Medicine, Institute of Genetics &Genomics in Geneva (iGE3), Faculty of Medicine, University of Geneva, CH-1211 Geneva, Switzerland
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25
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Abstract
Progression of the Caulobacter cell cycle requires temporal and spatial control of gene expression, culminating in an asymmetric cell division yielding distinct daughter cells. To explore the contribution of translational control, RNA-seq and ribosome profiling were used to assay global transcription and translation levels of individual genes at six times over the cell cycle. Translational efficiency (TE) was used as a metric for the relative rate of protein production from each mRNA. TE profiles with similar cell cycle patterns were found across multiple clusters of genes, including those in operons or in subsets of operons. Collections of genes associated with central cell cycle functional modules (e.g., biosynthesis of stalk, flagellum, or chemotaxis machinery) have consistent but different TE temporal patterns, independent of their operon organization. Differential translation of operon-encoded genes facilitates precise cell cycle-timing for the dynamic assembly of multiprotein complexes, such as the flagellum and the stalk and the correct positioning of regulatory proteins to specific cell poles. The cell cycle-regulatory pathways that produce specific temporal TE patterns are separate from-but highly coordinated with-the transcriptional cell cycle circuitry, suggesting that the scheduling of translational regulation is organized by the same cyclical regulatory circuit that directs the transcriptional control of the Caulobacter cell cycle.
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26
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Sumares JAP, Morão LG, Martins PMM, Martins DAB, Gomes E, Belasque J, Ferreira H. Temperature stress promotes cell division arrest in Xanthomonas citri subsp. citri. Microbiologyopen 2015; 5:244-53. [PMID: 26663580 PMCID: PMC4831469 DOI: 10.1002/mbo3.323] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/02/2015] [Accepted: 11/06/2015] [Indexed: 11/10/2022] Open
Abstract
Citrus canker is an economically important disease that affects orange production in some of the most important producing areas around the world. It represents a great threat to the Brazilian and North American citriculture, particularly to the states of São Paulo and Florida, which together correspond to the biggest orange juice producers in the world. The etiological agent of this disease is the Gram‐negative bacterium Xanthomonas citri subsp. citri (Xcc), which grows optimally in laboratory cultures at ~30°C. To investigate how temperatures differing from 30°C influence the development of Xcc, we subjected the bacterium to thermal stresses, and afterward scored its recovery capability. In addition, we analyzed cell morphology and some markers of essential cellular processes that could indicate the extent of the heat‐induced damage. We found that the exposure of Xcc to 37°C for a period of 6 h led to a cell cycle arrest at the division stage. Thermal stress might have also interfered with the DNA replication and/or the chromosome segregation apparatuses, since cells displayed an increased number of sister origins side‐by‐side within rods. Additionally, Xcc treated at 37°C was still able to induce citrus canker symptoms, showing that thermal stress did not affect the ability of Xcc to colonize the host citrus. At 40–42°C, Xcc lost viability and became unable to induce disease symptoms in citrus. Our results provide evidence about essential cellular mechanisms perturbed by temperature, and can be potentially explored as a new method for Xanthomonas citri synchronization in cell cycle studies, as well as for the sanitation of plant material.
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Affiliation(s)
- Júlia A P Sumares
- Faculdade de Ciências Farmacêuticas, Depto. de Ciências Biológicas, Universidade Estadual Paulista, Rodovia Araraquara/Jaú Km 1, CP 502, Araraquara, SP, 14801-902, Brazil
| | - Luana Galvão Morão
- Depto. Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Av. 24A 1515, Rio Claro, SP, 13506-900, Brazil
| | - Paula M M Martins
- Depto. Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Av. 24A 1515, Rio Claro, SP, 13506-900, Brazil
| | - Daniela A B Martins
- Depto. de Bioquímica e Tecnologia Química, Instituto de Química, Universidade Estadual Paulista, R. Prof. Francisco Degni, 55, Araraquara, SP, 14800-060, Brazil
| | - Eleni Gomes
- Depto. de Biologia, Universidade Estadual Paulista, Rua Cristóvão Colombo, 2265 Jardim Nazareth, São Jose do Rio Preto, SP, 15054-000, Brazil
| | - José Belasque
- Depto. de Fitopatologia e Nematologia, Escola Superior de Agricultura "Luiz de Queiroz", Universidade de São Paulo, Av. Pádua Dias 11, Piracicaba, SP, 13418-900, Brazil
| | - Henrique Ferreira
- Depto. Bioquímica e Microbiologia, Instituto de Biociências, Universidade Estadual Paulista, Av. 24A 1515, Rio Claro, SP, 13506-900, Brazil
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