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Morgene F, Rizoug Zeghlache C, Feng SY, Hauck Y, Mirouze N. Natural transformation and cell division delay in competent Staphylococcus aureus. Microbiol Spectr 2023; 11:e0280723. [PMID: 37831481 PMCID: PMC10714784 DOI: 10.1128/spectrum.02807-23] [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: 07/26/2023] [Accepted: 09/01/2023] [Indexed: 10/14/2023] Open
Abstract
IMPORTANCE Natural transformation, considered one of the three main mechanisms leading to horizontal gene transfer in bacteria, is able to promote genomic plasticity and foster antibiotic resistance spreading. Conserved machinery and actors required to perform natural transformation have been shown to accumulate at different cellular localizations depending on the model organism considered. Here, we show in the human pathogen Staphylococcus aureus that DNA binding, uptake, and recombination are spatially and temporally coordinated to ensure S. aureus natural transformation. We also reveal that localization of natural transformation proteins occurs in the vicinity of the division septum allowing S. aureus competent cells to block cell division to ensure the success of natural transformation before the final constriction of the cytokinetic ring.
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Affiliation(s)
- Fedy Morgene
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Célia Rizoug Zeghlache
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Shi Yuan Feng
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Yolande Hauck
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
| | - Nicolas Mirouze
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), Gif-sur-Yvette, France
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2
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Zuke JD, Erickson R, Hummels KR, Burton BM. Visualizing dynamic competence pili and DNA capture throughout the long axis of Bacillus subtilis. J Bacteriol 2023; 205:e0015623. [PMID: 37695859 PMCID: PMC10521363 DOI: 10.1128/jb.00156-23] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/05/2023] [Indexed: 09/13/2023] Open
Abstract
The first step in the process of bacterial natural transformation is DNA capture. Although long hypothesized based on genetics and functional experiments, the pilus structure responsible for initial DNA binding had not yet been visualized for Bacillus subtilis. Here, we visualize functional competence pili in Bacillus subtilis using fluorophore-conjugated maleimide labeling in conjunction with epifluorescence microscopy. In strains that produce pilin monomers within tenfold of wild-type levels, the median length of detectable pili is 300 nm. These pili are retractile and associate with DNA. The analysis of pilus distribution at the cell surface reveals that they are predominantly located along the long axis of the cell. The distribution is consistent with localization of proteins associated with subsequent transformation steps, DNA binding, and DNA translocation in the cytosol. These data suggest a distributed model for B. subtilis transformation machinery, in which initial steps of DNA capture occur throughout the long axis of the cell and subsequent steps may also occur away from the cell poles. IMPORTANCE This work provides novel visual evidence for DNA translocation across the cell wall during Bacillus subtilis natural competence, an essential step in the natural transformation process. Our data demonstrate the existence of natural competence-associated retractile pili that can bind exogenous DNA. Furthermore, we show that pilus biogenesis occurs throughout the cell long axis. These data strongly support DNA translocation occurring all along the lateral cell wall during natural competence, wherein pili are produced, bind to free DNA in the extracellular space, and finally retract to pull the bound DNA through the gap in the cell wall created during pilus biogenesis.
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Affiliation(s)
- Jason D. Zuke
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
- Microbiology Doctoral Training Program, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Rachel Erickson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
| | - Katherine R. Hummels
- Department of Microbiology and Immunology, Harvard Medical School, Boston, MA, USA
| | - Briana M. Burton
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA
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3
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Zuke JD, Erickson R, Hummels KR, Burton BM. Visualizing dynamic competence pili and DNA capture throughout the long axis of Bacillus subtilis. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.26.542325. [PMID: 37292776 PMCID: PMC10246001 DOI: 10.1101/2023.05.26.542325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The first step in the process of bacterial natural transformation is DNA capture. Although long-hypothesized based on genetics and functional experiments, the pilus structure responsible for initial DNA-binding had not yet been visualized for Bacillus subtilis. Here, we visualize functional competence pili in Bacillus subtilis using fluorophore-conjugated maleimide labeling in conjunction with epifluorescence microscopy. In strains that produce pilin monomers within ten-fold of wild type levels, the median length of detectable pili is 300nm. These pili are retractile and associate with DNA. Analysis of pilus distribution at the cell surface reveals that they are predominantly located along the long axis of the cell. The distribution is consistent with localization of proteins associated with subsequent transformation steps, DNA-binding and DNA translocation in the cytosol. These data suggest a distributed model for B. subtilis transformation machinery, in which initial steps of DNA capture occur throughout the long axis of the cell and subsequent steps may also occur away from the cell poles.
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Affiliation(s)
- Jason D. Zuke
- Department of Bacteriology, University of Wisconsin - Madison
- Microbiology Doctoral Training Program, University of Wisconsin - Madison
| | - Rachel Erickson
- Department of Bacteriology, University of Wisconsin - Madison
| | - Katherine R. Hummels
- Current address: Department of Microbiology and Immunology, Harvard Medical School
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4
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Lou J, Wang J, Yang Y, Yang Q, LI R, Hu M, He Q, Du J, Wang X, Li M, Yang S. Development and characterization of efficient xylose utilization strains of Zymomonas mobilis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:231. [PMID: 34863266 PMCID: PMC8645129 DOI: 10.1186/s13068-021-02082-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 11/19/2021] [Indexed: 05/15/2023]
Abstract
BACKGROUND Efficient use of glucose and xylose is a key for the economic production of lignocellulosic biofuels and biochemicals, and different recombinant strains have been constructed for xylose utilization including those using Zymomonas mobilis as the host. However, the xylose utilization efficiency still needs to be improved. In this work, the strategy of combining metabolic engineering and adaptive laboratory evolution (ALE) was employed to develop recombinant Z. mobilis strains that can utilize xylose efficiently at high concentrations, and NGS-based genome resequencing and RNA-Seq transcriptomics were performed for strains evolved after serial transfers in different media to understand the impact of xylose and differences among strains with different xylose-utilization capabilities at molecular level. RESULTS Heterologous genes encoding xylose isomerase and xylulokinase were evaluated, which were then introduced into xylose-utilizing strain Z. mobilis 8b to enhance its capacity of xylose utilization. The results demonstrated that the effect of three xylose isomerases on xylose utilization was different, and the increase of copy number of xylose metabolism genes can improve xylose utilization. Among various recombinant strains constructed, the xylose utilization capacity of the recombinant strain 8b-RsXI-xylB was the best, which was further improved through continuous adaption with 38 transfers over 100 days in 50 g/L xylose media. The fermentation performances of the parental strain 8b, the evolved 8b-S38 strain with the best xylose utilization capability, and the intermediate strain 8b-S8 in different media were compared, and the results showed that only 8b-S38 could completely consume xylose at 50 g/L and 100 g/L concentrations. In addition, the xylose consumption rate of 8b-S38 was faster than that of 8b at different xylose concentrations from 50 to 150 g/L, and the ethanol yield increased by 16 ~ 40%, respectively. The results of the mixed-sugar fermentation also demonstrated that 8b-S38 had a higher xylose consumption rate than 8b, and its maximum ethanol productivity was 1.2 ~ 1.4 times higher than that of 8b and 8b-S8. Whole-genome resequencing identified three common genetic changes in 8b-S38 compared with 8b and 8b-S8. RNA-Seq study demonstrated that the expression levels of genes encoding chaperone proteins, ATP-dependent proteases, phage shock proteins, ribosomal proteins, flagellar operons, and transcriptional regulators were significantly increased in xylose media in 8b-S38. The up-regulated expression of these genes may therefore contribute to the efficient xylose utilization of 8b-S38 by maintaining the normal cell metabolism and growth, repairing cellular damages, and rebalancing cellular energy to help cells resist the stressful environment. CONCLUSIONS This study provides gene candidates to improve xylose utilization, and the result of expressing an extra copy of xylose isomerase and xylulokinase improved xylose utilization also provides a direction for efficient xylose-utilization strain development in other microorganisms. In addition, this study demonstrated the necessity to combine metabolic engineering and ALE for industrial strain development. The recombinant strain 8b-S38 can efficiently metabolize xylose for ethanol fermentation at high xylose concentrations as well as in mixed sugars of glucose and xylose, which could be further developed as the microbial biocatalyst for the production of lignocellulosic biofuels and biochemicals.
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Affiliation(s)
- Jiyun Lou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jingwen Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qing Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Runxia LI
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mimi Hu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Qiaoning He
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Jun Du
- China Biotech Fermentation Industry Association, Beijing, 100833 China
| | - Xia Wang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
| | - Mian Li
- Zhejiang Huakang Pharmaceutical Co., Ltd., Kaihua County, Zhejiang, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, 430062 China
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5
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Huang M, Liu M, Huang L, Wang M, Jia R, Zhu D, Chen S, Zhao X, Zhang S, Gao Q, Zhang L, Cheng A. The activation and limitation of the bacterial natural transformation system: The function in genome evolution and stability. Microbiol Res 2021; 252:126856. [PMID: 34454311 DOI: 10.1016/j.micres.2021.126856] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2021] [Revised: 08/19/2021] [Accepted: 08/22/2021] [Indexed: 12/26/2022]
Abstract
Bacteria can take up exogenous naked DNA and integrate it into their genomes, which has been regarded as a main contributor to bacterial evolution. The competent status of bacteria is influenced by environmental cues and by the immune systems of bacteria. Here, we review recent advances in understanding the working mechanisms underlying activation of the natural transformation system and limitations thereof. Environmental stresses including the presence of antimicrobials can activate the natural transformation system. However, bacterial enzymes (nucleases), non-coding RNAs, specific DNA sequences, the restriction-modification (R-M) systems, CRISPR-Cas systems and prokaryotic Argonaute proteins (Agos) are have been found to be involved in the limitation of the natural transformation system. Together, this review represents an opportunity to gain insight into bacterial genome stability and evolution.
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Affiliation(s)
- Mi Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Mafeng Liu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Li Huang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Mingshu Wang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Renyong Jia
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Dekang Zhu
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Shun Chen
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Xinxin Zhao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Shaqiu Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Qun Gao
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Ling Zhang
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China
| | - Anchun Cheng
- Institute of Preventive Veterinary Medicine, Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Research Centre of Avian Disease, College of Veterinary Medicine of Sichuan Agricultural University, Chengdu, Sichuan, 611130, PR China; Key Laboratory of Animal Disease and Human Health of Sichuan Province, Chengdu, Sichuan, 611130, PR China.
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6
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Cardiolipin-Containing Lipid Membranes Attract the Bacterial Cell Division Protein DivIVA. Int J Mol Sci 2021; 22:ijms22158350. [PMID: 34361115 PMCID: PMC8348161 DOI: 10.3390/ijms22158350] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2021] [Revised: 07/28/2021] [Accepted: 08/01/2021] [Indexed: 02/04/2023] Open
Abstract
DivIVA is a protein initially identified as a spatial regulator of cell division in the model organism Bacillus subtilis, but its homologues are present in many other Gram-positive bacteria, including Clostridia species. Besides its role as topological regulator of the Min system during bacterial cell division, DivIVA is involved in chromosome segregation during sporulation, genetic competence, and cell wall synthesis. DivIVA localizes to regions of high membrane curvature, such as the cell poles and cell division site, where it recruits distinct binding partners. Previously, it was suggested that negative curvature sensing is the main mechanism by which DivIVA binds to these specific regions. Here, we show that Clostridioides difficile DivIVA binds preferably to membranes containing negatively charged phospholipids, especially cardiolipin. Strikingly, we observed that upon binding, DivIVA modifies the lipid distribution and induces changes to lipid bilayers containing cardiolipin. Our observations indicate that DivIVA might play a more complex and so far unknown active role during the formation of the cell division septal membrane.
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7
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Labana P, Dornan MH, Lafrenière M, Czarny TL, Brown ED, Pezacki JP, Boddy CN. Armeniaspirols inhibit the AAA+ proteases ClpXP and ClpYQ leading to cell division arrest in Gram-positive bacteria. Cell Chem Biol 2021; 28:1703-1715.e11. [PMID: 34293284 DOI: 10.1016/j.chembiol.2021.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Revised: 04/22/2021] [Accepted: 06/29/2021] [Indexed: 01/16/2023]
Abstract
Multi-drug-resistant bacteria present an urgent threat to modern medicine, creating a desperate need for antibiotics with new modes of action. As natural products remain an unsurpassed source for clinically viable antibiotic compounds, we investigate the mechanism of action of armeniaspirol. The armeniaspirols are a structurally unique class of Gram-positive antibiotic discovered from Streptomyces armeniacus for which resistance cannot be readily obtained. We show that armeniaspirol inhibits the ATP-dependent proteases ClpXP and ClpYQ in vitro and in the model Gram-positive Bacillus subtilis. This inhibition dysregulates the divisome and elongasome supported by an upregulation of key proteins FtsZ, DivIVA, and MreB inducing cell division arrest. The inhibition of ClpXP and ClpYQ to dysregulate cell division represents a unique antibiotic mechanism of action and armeniaspirol is the only known natural product inhibitor of the coveted anti-virulence target ClpP. Thus, armeniaspirol possesses a promising lead scaffold for antibiotic development with unique pharmacology.
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Affiliation(s)
- Puneet Labana
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Mark H Dornan
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Matthew Lafrenière
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Tomasz L Czarny
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Eric D Brown
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - John P Pezacki
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada
| | - Christopher N Boddy
- Department of Chemistry and Biomolecular Sciences, University of Ottawa, Ottawa, ON K1N 6N5, Canada.
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8
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Sharma K, Sultana T, Dahms TES, Dillon JAR. CcpN: a moonlighting protein regulating catabolite repression of gluconeogenic genes in Bacillus subtilis also affects cell length and interacts with DivIVA. Can J Microbiol 2020; 66:723-732. [PMID: 32762636 DOI: 10.1139/cjm-2020-0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
CcpN is a transcriptional repressor in Bacillus subtilis that binds to the promoter region of gapB and pckA, downregulating their expression in the presence of glucose. CcpN also represses sr1, which encodes a small noncoding regulatory RNA that suppresses the arginine biosynthesis gene cluster. CcpN has homologues in other Gram-positive bacteria, including Enterococcus faecalis. We report the interaction of CcpN with DivIVA of B. subtilis as determined using bacterial two-hybrid and glutathione S-transferase pull-down assays. Insertional inactivation of CcpN leads to cell elongation and formation of straight chains of cells. These findings suggest that CcpN is a moonlighting protein involved in both gluconeogenesis and cell elongation.
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Affiliation(s)
- Kusum Sharma
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada.,Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada
| | - Taranum Sultana
- Department of Chemistry and Biochemistry, 3737 Wascana Parkway, University of Regina, Regina, SK S4S 0A2, Canada
| | - Tanya E S Dahms
- Department of Chemistry and Biochemistry, 3737 Wascana Parkway, University of Regina, Regina, SK S4S 0A2, Canada
| | - Jo-Anne R Dillon
- Department of Biochemistry, Microbiology and Immunology, College of Medicine, University of Saskatchewan, 107 Wiggins Road, Saskatoon, SK S7N 5E5, Canada.,Vaccine and Infectious Disease Organization, University of Saskatchewan, 120 Veterinary Road, Saskatoon, SK S7N 5E3, Canada
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9
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Boonstra M, Schaffer M, Sousa J, Morawska L, Holsappel S, Hildebrandt P, Sappa PK, Rath H, de Jong A, Lalk M, Mäder U, Völker U, Kuipers OP. Analyses of competent and non-competent subpopulations of Bacillus subtilis reveal yhfW, yhxC and ncRNAs as novel players in competence. Environ Microbiol 2020; 22:2312-2328. [PMID: 32249531 PMCID: PMC7317962 DOI: 10.1111/1462-2920.15005] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2019] [Accepted: 03/29/2020] [Indexed: 11/28/2022]
Abstract
Upon competence-inducing nutrient-limited conditions, only part of the Bacillus subtilis population becomes competent. Here, we separated the two subpopulations by fluorescence-assisted cell sorting (FACS). Using RNA-seq, we confirmed the previously described ComK regulon. We also found for the first time significantly downregulated genes in the competent subpopulation. The downregulated genes are not under direct control by ComK but have higher levels of corresponding antisense RNAs in the competent subpopulation. During competence, cell division and replication are halted. By investigating the proteome during competence, we found higher levels of the regulators of cell division, MinD and Noc. The exonucleases SbcC and SbcD were also primarily regulated at the post-transcriptional level. In the competent subpopulation, yhfW was newly identified as being highly upregulated. Its absence reduces the expression of comG, and has a modest, but statistically significant effect on the expression of comK. Although expression of yhfW is higher in the competent subpopulation, no ComK-binding site is present in its promoter region. Mutants of yhfW have a small but significant defect in transformation. Metabolomic analyses revealed significant reductions in tricarboxylic acid (TCA) cycle metabolites and several amino acids in a ΔyhfW mutant. RNA-seq analysis of ΔyhfW revealed higher expression of the NAD synthesis genes nadA, nadB and nadC.
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Affiliation(s)
- Mirjam Boonstra
- Molecular Genetics group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, the Netherlands
| | - Marc Schaffer
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Joana Sousa
- Department of Cellular Biochemistry/Metabolomics, Institute of Biochemistry, University of Greifswald, Germany
| | - Luiza Morawska
- Molecular Genetics group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, the Netherlands
| | - Siger Holsappel
- Molecular Genetics group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, the Netherlands
| | - Petra Hildebrandt
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Praveen Kumar Sappa
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Hermann Rath
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Anne de Jong
- Molecular Genetics group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, the Netherlands
| | - Michael Lalk
- Department of Cellular Biochemistry/Metabolomics, Institute of Biochemistry, University of Greifswald, Germany
| | - Ulrike Mäder
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Uwe Völker
- Department of Functional Genomics, Interfaculty Institute of Genetics and Functional Genomics, University Medicine Greifswald, Germany
| | - Oscar P Kuipers
- Molecular Genetics group, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, the Netherlands
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10
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Sharma K, Sultana T, Liao M, Dahms TES, Dillon JAR. EF1025, a Hypothetical Protein From Enterococcus faecalis, Interacts With DivIVA and Affects Cell Length and Cell Shape. Front Microbiol 2020; 11:83. [PMID: 32117116 PMCID: PMC7028823 DOI: 10.3389/fmicb.2020.00083] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Accepted: 01/15/2020] [Indexed: 01/22/2023] Open
Abstract
DivIVA plays multifaceted roles in Gram-positive organisms through its association with various cell division and non-cell division proteins. We report a novel DivIVA interacting protein in Enterococcus faecalis, named EF1025 (encoded by EF1025), which is conserved in Gram-positive bacteria. The interaction of EF1025 with DivIVAEf was confirmed by Bacterial Two-Hybrid, Glutathione S-Transferase pull-down, and co-immunoprecipitation assays. EF1025, which contains a DNA binding domain and two Cystathionine β-Synthase (CBS) domains, forms a decamer mediated by the two CBS domains. Viable cells were recovered after insertional inactivation or deletion of EF1025 only through complementation of EF1025 in trans. These cells were longer than the average length of E. faecalis cells and had distorted shapes. Overexpression of EF1025 also resulted in cell elongation. Immuno-staining revealed comparable localization patterns of EF1025 and DivIVAEf in the later stages of division in E. faecalis cells. In summary, EF1025 is a novel DivIVA interacting protein influencing cell length and morphology in E. faecalis.
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Affiliation(s)
- Kusum Sharma
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
- Vaccine and Infectious Disease Organization – International Vaccine Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Taranum Sultana
- Department of Chemistry and Biochemistry, University of Regina, Regina, SK, Canada
| | - Mingmin Liao
- Vaccine and Infectious Disease Organization – International Vaccine Centre, University of Saskatchewan, Saskatoon, SK, Canada
| | - Tanya E. S. Dahms
- Department of Chemistry and Biochemistry, University of Regina, Regina, SK, Canada
| | - Jo-Anne R. Dillon
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, SK, Canada
- Vaccine and Infectious Disease Organization – International Vaccine Centre, University of Saskatchewan, Saskatoon, SK, Canada
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11
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Martin HA, Kidman AA, Socea J, Vallin C, Pedraza-Reyes M, Robleto EA. The Bacillus Subtilis K-State Promotes Stationary-Phase Mutagenesis via Oxidative Damage. Genes (Basel) 2020; 11:genes11020190. [PMID: 32053972 PMCID: PMC7073564 DOI: 10.3390/genes11020190] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 02/05/2020] [Accepted: 02/06/2020] [Indexed: 12/12/2022] Open
Abstract
Bacterial cells develop mutations in the absence of cellular division through a process known as stationary-phase or stress-induced mutagenesis. This phenomenon has been studied in a few bacterial models, including Escherichia coli and Bacillus subtilis; however, the underlying mechanisms between these systems differ. For instance, RecA is not required for stationary-phase mutagenesis in B. subtilis like it is in E. coli. In B. subtilis, RecA is essential to the process of genetic transformation in the subpopulation of cells that become naturally competent in conditions of stress. Interestingly, the transcriptional regulator ComK, which controls the development of competence, does influence the accumulation of mutations in stationary phase in B. subtilis. Since recombination is not involved in this process even though ComK is, we investigated if the development of a subpopulation (K-cells) could be involved in stationary-phase mutagenesis. Using genetic knockout strains and a point-mutation reversion system, we investigated the effects of ComK, ComEA (a protein involved in DNA transport during transformation), and oxidative damage on stationary-phase mutagenesis. We found that stationary-phase revertants were more likely to have undergone the development of competence than the background of non-revertant cells, mutations accumulated independently of DNA uptake, and the presence of exogenous oxidants potentiated mutagenesis in K-cells. Therefore, the development of the K-state creates conditions favorable to an increase in the genetic diversity of the population not only through exogenous DNA uptake but also through stationary-phase mutagenesis.
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Affiliation(s)
- Holly A. Martin
- University of Nevada, Las Vegas, 4505 S Maryland Pkwy, Las Vegas, NV 89154, USA; (H.A.M.); (A.A.K.); (J.S.); (C.V.)
| | - Amanda A. Kidman
- University of Nevada, Las Vegas, 4505 S Maryland Pkwy, Las Vegas, NV 89154, USA; (H.A.M.); (A.A.K.); (J.S.); (C.V.)
| | - Jillian Socea
- University of Nevada, Las Vegas, 4505 S Maryland Pkwy, Las Vegas, NV 89154, USA; (H.A.M.); (A.A.K.); (J.S.); (C.V.)
| | - Carmen Vallin
- University of Nevada, Las Vegas, 4505 S Maryland Pkwy, Las Vegas, NV 89154, USA; (H.A.M.); (A.A.K.); (J.S.); (C.V.)
| | - Mario Pedraza-Reyes
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, P.O. Box 187, Guanajuato Gto. 36050, Mexico;
| | - Eduardo A. Robleto
- University of Nevada, Las Vegas, 4505 S Maryland Pkwy, Las Vegas, NV 89154, USA; (H.A.M.); (A.A.K.); (J.S.); (C.V.)
- Correspondence: ; Tel.: +1-702-895-2496
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12
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Burghard-Schrod M, Altenburger S, Graumann PL. The Bacillus subtilis dCMP deaminase ComEB acts as a dynamic polar localization factor for ComGA within the competence machinery. Mol Microbiol 2020; 113:906-922. [PMID: 31954084 DOI: 10.1111/mmi.14457] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Revised: 01/08/2020] [Accepted: 01/10/2020] [Indexed: 01/15/2023]
Abstract
Bacillus subtilis can import DNA from the environment by an uptake machinery that localizes to a single cell pole. We investigated the roles of ComEB and of the ATPase ComGA during the state of competence. We show that ComEB plays an important role during competence, possibly because it is necessary for the recruitment of GomGA to the cell pole. ComEB localizes to the cell poles even upon expression during exponential phase, indicating that it can serve as polar marker. ComEB is also a deoxycytidylate monophosphate (dCMP) deaminase, for the function of which a conserved cysteine residue is important. However, cysteine-mutant ComEB is still capable of natural transformation, while a comEB deletion strain is highly impaired in competence, indicating that ComEB confers two independent functions. Single-molecule tracking (SMT) reveals that both proteins exchange at the cell poles between bound and unbound in a time scale of a few milliseconds, but turnover of ComGA increases during DNA uptake, whereas the mobility of ComEB is not affected. Our data reveal a highly dynamic role of ComGA during DNA uptake and an unusual role for ComEB as a mediator of polar localization, localizing by diffusion-capture on an extremely rapid time scale and functioning as a moonlighting enzyme.
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Affiliation(s)
- Marie Burghard-Schrod
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.,Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Stephan Altenburger
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.,Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
| | - Peter L Graumann
- SYNMIKRO, LOEWE Center for Synthetic Microbiology, Marburg, Germany.,Department of Chemistry, Philipps Universität Marburg, Marburg, Germany
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13
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Abstract
Reproduction in the bacterial kingdom predominantly occurs through binary fission-a process in which one parental cell is divided into two similarly sized daughter cells. How cell division, in conjunction with cell elongation and chromosome segregation, is orchestrated by a multitude of proteins has been an active area of research spanning the past few decades. Together, the monumental endeavors of multiple laboratories have identified several cell division and cell shape regulators as well as their underlying regulatory mechanisms in rod-shaped Escherichia coli and Bacillus subtilis, which serve as model organisms for Gram-negative and Gram-positive bacteria, respectively. Yet our understanding of bacterial cell division and morphology regulation is far from complete, especially in noncanonical and non-rod-shaped organisms. In this review, we focus on two proteins that are highly conserved in Gram-positive organisms, DivIVA and its homolog GpsB, and attempt to summarize the recent advances in this area of research and discuss their various roles in cell division, cell growth, and chromosome segregation in addition to their interactome and posttranslational regulation.
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14
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Wang Y, Wang Y, Li J, Gong S, Sun L, Grenier D, Li Y. Pdh is involved in the cell division and Normal septation of Streptococcus suis. Microbiol Res 2019; 228:126304. [PMID: 31422235 DOI: 10.1016/j.micres.2019.126304] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2019] [Revised: 07/15/2019] [Accepted: 07/18/2019] [Indexed: 02/06/2023]
Abstract
Streptococcus suis (S. suis) is an important zoonotic pathogen that causes major economic losses in the pig industry worldwide. The S. suis cell division process is an integral part of its growth and reproduction, which is controlled by a complex regulatory network. Pyruvate dehydrogenase (PDH), which catalyzes the oxidative decarboxylation of pyruvate to form acetyl-CoA, while reducing NAD + to NADH, plays an important role in energy metabolism. Recently, we reported that pdh regulates virulence by reducing stress tolerance and biofilm formation in S. suis serotype 2. In this study, we found that deletion of the pdh gene in S. suis resulted in abnormal cell chains, plump morphology and abnormal localization of the Z rings, indicating that the knockout mutant is impaired in its ability to divide. In addition, the interaction between FtsZ and PDH in vitro was confirmed by ELISA, and qRT-PCR analysis revealed that the deletion of the pdh gene results in differential expression of the division-related genes ftsZ, ftsK, ftsl, zapA, divIC, pbp1a, rodA, mreD, and sepF. These results indicate that pdh is involved in the normal formation of Z rings and cell morphology during S. suis cell division.
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Affiliation(s)
- Yang Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China.
| | - Yuxin Wang
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Jinpeng Li
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Shenglong Gong
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Liyun Sun
- College of Animal Science and Technology, Henan University of Science and Technology, Luoyang, China; Key Laboratory of Molecular Pathogen and Immunology of Animal of Luoyang, Luoyang, China
| | - Daniel Grenier
- Groupe de Recherche en Écologie Buccale (GREB), Faculté de Médecine Dentaire, Université Laval, Quebec City, QC, Canada
| | - Yi Li
- College of Life Science, Luoyang Normal University, Luoyang, China.
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15
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Halbedel S, Lewis RJ. Structural basis for interaction of DivIVA/GpsB proteins with their ligands. Mol Microbiol 2019; 111:1404-1415. [PMID: 30887576 DOI: 10.1111/mmi.14244] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/13/2019] [Indexed: 01/06/2023]
Abstract
DivIVA proteins and their GpsB homologues are late cell division proteins found in Gram-positive bacteria. DivIVA/GpsB proteins associate with the inner leaflet of the cytosolic membrane and act as scaffolds for other proteins required for cell growth and division. DivIVA/GpsB proteins comprise an N-terminal lipid-binding domain for membrane association fused to C-terminal domains supporting oligomerization. Despite sharing the same domain organization, DivIVA and GpsB serve different cellular functions: DivIVA plays diverse roles in division site selection, chromosome segregation and controlling peptidoglycan homeostasis, whereas GpsB contributes to the spatiotemporal control of penicillin-binding protein activity. The crystal structures of the lipid-binding domains of DivIVA from Bacillus subtilis and GpsB from several species share a fold unique to this group of proteins, whereas the C-terminal domains of DivIVA and GpsB are radically different. A number of pivotal features identified from the crystal structures explain the functional differences between the proteins. Herein we discuss these structural and functional relationships and recent advances in our understanding of how DivIVA/GpsB proteins bind and recruit their interaction partners, knowledge that might be useful for future structure-based DivIVA/GpsB inhibitor design.
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Affiliation(s)
- Sven Halbedel
- FG11 Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute, Wernigerode, Germany
| | - Richard J Lewis
- Institute for Cell and Molecular Biosciences, University of Newcastle, Newcastle upon Tyne, NE2 4HH, United Kingdom
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16
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Martin HA, Porter KE, Vallin C, Ermi T, Contreras N, Pedraza-Reyes M, Robleto EA. Mfd protects against oxidative stress in Bacillus subtilis independently of its canonical function in DNA repair. BMC Microbiol 2019; 19:26. [PMID: 30691388 PMCID: PMC6350366 DOI: 10.1186/s12866-019-1394-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Accepted: 01/16/2019] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Previous reports showed that mutagenesis in nutrient-limiting conditions is dependent on Mfd in Bacillus subtilis. Mfd initiates one type of transcription-coupled repair (TCR); this type of repair is known to target bulky lesions, like those associated with UV exposure. Interestingly, the roles of Mfd in repair of oxidative-promoted DNA damage and regulation of transcription differ. Here, we used a genetic approach to test whether Mfd protected B. subtilis from exposure to two different oxidants. RESULTS Wild-type cells survived tert-butyl hydroperoxide (t-BHP) exposure significantly better than Mfd-deficient cells. This protective effect was independent of UvrA, a component of the canonical TCR/nucleotide excision repair (NER) pathway. Further, our results suggest that Mfd and MutY, a DNA glycosylase that processes 8-oxoG DNA mismatches, work together to protect cells from lesions generated by oxidative damage. We also tested the role of Mfd in mutagenesis in starved cells exposed to t-BHP. In conditions of oxidative stress, Mfd and MutY may work together in the formation of mutations. Unexpectedly, Mfd increased survival when cells were exposed to the protein oxidant diamide. Under this type of oxidative stress, cells survival was not affected by MutY or UvrA. CONCLUSIONS These results are significant because they show that Mfd mediates error-prone repair of DNA and protects cells against oxidation of proteins by affecting gene expression; Mfd deficiency resulted in increased gene expression of the OhrR repressor which controls the cellular response to organic peroxide exposure. These observations point to Mfd functioning beyond a DNA repair factor in cells experiencing oxidative stress.
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Affiliation(s)
- Holly Anne Martin
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada, 89154, USA
| | - Katelyn E Porter
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada, 89154, USA
| | - Carmen Vallin
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada, 89154, USA
| | - Tatiana Ermi
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada, 89154, USA
| | - Natalie Contreras
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada, 89154, USA
| | - Mario Pedraza-Reyes
- Department of Biology, Division of Natural and Exact Sciences, University of Guanajuato, P.O. Box 187, Gto. 36050, Guanajuato, Mexico
| | - Eduardo A Robleto
- School of Life Sciences, University of Nevada, Las Vegas, 4505 Maryland Parkway, Las Vegas, Nevada, 89154, USA.
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17
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Mirouze N, Ferret C, Cornilleau C, Carballido-López R. Antibiotic sensitivity reveals that wall teichoic acids mediate DNA binding during competence in Bacillus subtilis. Nat Commun 2018; 9:5072. [PMID: 30498236 PMCID: PMC6265299 DOI: 10.1038/s41467-018-07553-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 10/22/2018] [Indexed: 12/02/2022] Open
Abstract
Despite decades of investigation of genetic transformation in the model Gram-positive bacterium Bacillus subtilis, the factors responsible for exogenous DNA binding at the surface of competent cells remain to be identified. Here, we report that wall teichoic acids (WTAs), cell wall-anchored anionic glycopolymers associated to numerous critical functions in Gram-positive bacteria, are involved in this initial step of transformation. Using a combination of cell wall-targeting antibiotics and fluorescence microscopy, we show that competence-specific WTAs are produced and specifically localized in the competent cells to mediate DNA binding at the proximity of the transformation apparatus. Furthermore, we propose that TuaH, a putative glycosyl transferase induced during competence, modifies competence-induced WTAs in order to promote (directly or indirectly) DNA binding. On the basis of our results and previous knowledge in the field, we propose a model for DNA binding and transport during genetic transformation in B. subtilis. Natural genetic transformation in bacteria requires DNA binding at the surface of competent cells. Here, Mirouze et al. show that wall teichoic acids are specifically produced or modified during competence in Bacillus subtilis and promote (directly or indirectly) DNA binding at the cell surface.
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Affiliation(s)
- Nicolas Mirouze
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France. .,Institute for Integrative Biology of the Cell (I2BC), INSERM, CEA, CNRS, Université Paris-Sud, Orsay, 91190, Gif sur Yvette, France.
| | - Cécile Ferret
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
| | - Charlène Cornilleau
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France.,Inovarion, 75013, Paris, France
| | - Rut Carballido-López
- MICALIS, INRA, AgroParisTech, Université Paris-Saclay, 78350, Jouy-en-Josas, France
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18
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Improvement of butanol production by the development and co-culture of C. acetobutylicum TSH1 and B. cereus TSH2. Appl Microbiol Biotechnol 2018; 102:6753-6763. [DOI: 10.1007/s00253-018-9151-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2018] [Revised: 05/17/2018] [Accepted: 05/29/2018] [Indexed: 01/07/2023]
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19
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Nguyen LTT, Takemura AJ, Ohniwa RL, Saito S, Morikawa K. Sodium Polyanethol Sulfonate Modulates Natural Transformation of SigH-Expressing Staphylococcus aureus. Curr Microbiol 2017; 75:499-504. [DOI: 10.1007/s00284-017-1409-5] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 11/29/2017] [Indexed: 11/28/2022]
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20
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A programmed cell division delay preserves genome integrity during natural genetic transformation in Streptococcus pneumoniae. Nat Commun 2017; 8:1621. [PMID: 29158515 PMCID: PMC5696345 DOI: 10.1038/s41467-017-01716-9] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 10/11/2017] [Indexed: 11/22/2022] Open
Abstract
Competence for genetic transformation is a differentiation program during which exogenous DNA is imported into the cell and integrated into the chromosome. In Streptococcus pneumoniae, competence develops transiently and synchronously in all cells during exponential phase, and is accompanied by a pause in growth. Here, we reveal that this pause is linked to the cell cycle. At least two parallel pathways impair peptidoglycan synthesis in competent cells. Single-cell analyses demonstrate that ComM, a membrane protein induced during competence, inhibits both initiation of cell division and final constriction of the cytokinetic ring. Competence also interferes with the activity of the serine/threonine kinase StkP, the central regulator of pneumococcal cell division. We further present evidence that the ComM-mediated delay in division preserves genomic integrity during transformation. We propose that cell division arrest is programmed in competent pneumococcal cells to ensure that transformation is complete before resumption of cell division, to provide this pathogen with the maximum potential for genetic diversity and adaptation. In Streptococcus pneumoniae, competence for genetic transformation is accompanied by a pause in growth. Here, Bergé et al. show that this pause is linked to the cell cycle via at least two pathways that impair peptidoglycan synthesis and preserve genomic integrity during transformation.
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21
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Genetic Dissection of DivIVA Functions in Listeria monocytogenes. J Bacteriol 2017; 199:JB.00421-17. [PMID: 28972021 DOI: 10.1128/jb.00421-17] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2017] [Accepted: 09/22/2017] [Indexed: 12/30/2022] Open
Abstract
DivIVA is a membrane binding protein that clusters at curved membrane regions, such as the cell poles and the membrane invaginations occurring during cell division. DivIVA proteins recruit many other proteins to these subcellular sites through direct protein-protein interactions. DivIVA-dependent functions are typically associated with cell growth and division, even though species-specific differences in the spectrum of DivIVA functions and their causative interaction partners exist. DivIVA from the Gram-positive human pathogen Listeria monocytogenes has at least three different functions. In this bacterium, DivIVA is required for precise positioning of the septum at midcell, it contributes to the secretion of autolysins required for the breakdown of peptidoglycan at the septum after the completion of cell division, and it is essential for flagellar motility. While the DivIVA interaction partners for control of division site selection are well established, the proteins connecting DivIVA with autolysin secretion or swarming motility are completely unknown. We set out to identify divIVA alleles in which these three DivIVA functions could be separated, since the question of the degree to which the three functions of L. monocytogenes DivIVA are interlinked could not be answered before. Here, we identify such alleles, and our results show that division site selection, autolysin secretion, and swarming represent three discrete pathways that are independently influenced by DivIVA. These findings provide the required basis for the identification of DivIVA interaction partners controlling autolysin secretion and swarming in the future.IMPORTANCE DivIVA of the pathogenic bacterium Listeria monocytogenes is a central scaffold protein that influences at least three different cellular processes, namely, cell division, protein secretion, and bacterial motility. How DivIVA coordinates these rather unrelated processes is not known. We here identify variants of L. monocytogenes DivIVA, in which these functions are separated from each other. These results have important implications for the models explaining how DivIVA interacts with other proteins.
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22
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Shen Q, Tan H, Xing GW, Zheng J, Jia Z. A new method to investigate the catalytic mechanism of YhdE pyrophosphatase by using a pyrophosphate fluorescence probe. Sci Rep 2017; 7:8169. [PMID: 28811554 PMCID: PMC5557916 DOI: 10.1038/s41598-017-08368-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Accepted: 07/11/2017] [Indexed: 01/27/2023] Open
Abstract
YhdE is a Maf (multicopy associated filamentation) proteins from Escherichia coli which exhibits pyrophosphatase activity towards selected nucleotides, although its catalytic mechanism remains unclear. Herein we used a novel fluorescence probe (4-isoACBA–Zn(II) complex) to characterize the enzymatic properties of YhdE and its mutant, establishing a new method for assaying pyrophosphatase catalytic function. Our results reveal for the first time that the new fluorescence sensor confers high sensitivity and specificity and pyrophosphate (PPi) is the direct catalytic product of YhdE. Crystal structures of a mutant in the active-site loop (YhdE_E33A) show conformational flexibility implicated in the catalytic mechanism of YhdE. ITC experiments and computational docking further reveal that Asp70 and substrate dTTP coordinate Mn2+. Quantum mechanics calculations indicate that YhdE hydrolysis appears to follow a stepwise pathway in which a water molecule first attacks the α-phosphorus atom in the substrate, followed by the release of PPi from the pentavalent intermediate.
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Affiliation(s)
- Qingya Shen
- College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Hongwei Tan
- College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Guo-Wen Xing
- College of Chemistry, Beijing Normal University, Beijing, 100875, China
| | - Jimin Zheng
- College of Chemistry, Beijing Normal University, Beijing, 100875, China.
| | - Zongchao Jia
- Department of Biochemical and Molecular Science, Queen's University, Kingston, Ontario, K7L 3N6, Canada.
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23
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Abstract
For years intermediate filaments (IF), belonging to the third class of filamentous cytoskeletal proteins alongside microtubules and actin filaments, were thought to be exclusive to metazoan cells. Structurally these eukaryote IFs are very well defined, consisting of globular head and tail domains, which flank the central rod-domain. This central domain is dominated by an α-helical secondary structure predisposed to form the characteristic coiled-coil, parallel homo-dimer. These elementary dimers can further associate, both laterally and longitudinally, generating a variety of filament-networks built from filaments in the range of 10 nm in diameter. The general role of these filaments with their characteristic mechano-elastic properties both in the cytoplasm and in the nucleus of eukaryote cells is to provide mechanical strength and a scaffold supporting diverse shapes and cellular functions.Since 2003, after the first bacterial IF-like protein, crescentin was identified, it has been evident that bacteria also employ filamentous networks, other than those built from bacterial tubulin or actin homologues, in order to support their cell shape, growth and, in some cases, division. Intriguingly, compared to their eukaryote counterparts, the group of bacterial IF-like proteins shows much wider structural diversity. The sizes of both the head and tail domains are markedly reduced and there is great variation in the length of the central rod-domain. Furthermore, bacterial rod-domains often lack the sub-domain organisation of eukaryote IFs that is the defining feature of the IF-family. However, the fascinating display of filamentous assemblies, including rope, striated cables and hexagonal laces together with the conditions required for their formation both in vitro and in vivo strongly resemble that of eukaryote IFs suggesting that these bacterial proteins are deservedly classified as part of the IF-family and that the current definition should be relaxed slightly to allow their inclusion. The lack of extensive head and tail domains may well make the bacterial proteins more amenable for structural characterisation, which will be essential for establishing the mechanism for their association into filaments. What is more, the well-developed tools for bacterial manipulations provide an excellent opportunity of studying the bacterial systems with the prospect of making significant progress in our understanding of the general underlying principles of intermediate filament assemblies.
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Affiliation(s)
- Gabriella H Kelemen
- School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK.
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24
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Schumacher MA. Bacterial Nucleoid Occlusion: Multiple Mechanisms for Preventing Chromosome Bisection During Cell Division. Subcell Biochem 2017; 84:267-298. [PMID: 28500529 DOI: 10.1007/978-3-319-53047-5_9] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In most bacteria cell division is driven by the prokaryotic tubulin homolog, FtsZ, which forms the cytokinetic Z ring. Cell survival demands both the spatial and temporal accuracy of this process to ensure that equal progeny are produced with intact genomes. While mechanisms preventing septum formation at the cell poles have been known for decades, the means by which the bacterial nucleoid is spared from bisection during cell division, called nucleoid exclusion (NO), have only recently been deduced. The NO theory was originally posited decades ago based on the key observation that the cell division machinery appeared to be inhibited from forming near the bacterial nucleoid. However, what might drive the NO process was unclear. Within the last 10 years specific proteins have been identified as important mediators of NO. Arguably the best studied NO mechanisms are those employed by the Escherichia coli SlmA and Bacillus subtilis Noc proteins. Both proteins bind specific DNA sequences within selected chromosomal regions to act as timing devices. However, Noc and SlmA contain completely different structural folds and utilize distinct NO mechanisms. Recent studies have identified additional processes and factors that participate in preventing nucleoid septation during cell division. These combined data show multiple levels of redundancy as well as a striking diversity of mechanisms have evolved to protect cells against catastrophic bisection of the nucleoid. Here we discuss these recent findings with particular emphasis on what is known about the molecular underpinnings of specific NO machinery and processes.
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Affiliation(s)
- Maria A Schumacher
- Department of Biochemistry, Duke University School of Medicine, 243 Nanaline H. Duke, Durham, NC, 27710, USA.
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25
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Miras M, Dubnau D. A DegU-P and DegQ-Dependent Regulatory Pathway for the K-state in Bacillus subtilis. Front Microbiol 2016; 7:1868. [PMID: 27920766 PMCID: PMC5118428 DOI: 10.3389/fmicb.2016.01868] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Accepted: 11/07/2016] [Indexed: 12/04/2022] Open
Abstract
The K-state in the model bacterium Bacillus subtilis is associated with transformability (competence) as well as with growth arrest and tolerance for antibiotics. Entry into the K-state is determined by the stochastic activation of the transcription factor ComK and occurs in about ∼15% of the population in domesticated strains. Although the upstream mechanisms that regulate the K-state have been intensively studied and are well understood, it has remained unexplained why undomesticated isolates of B. subtilis are poorly transformable compared to their domesticated counterparts. We show here that this is because fewer cells enter the K-state, suggesting that a regulatory pathway limiting entry to the K-state is missing in domesticated strains. We find that loss of this limitation is largely due to an inactivating point mutation in the promoter of degQ. The resulting low level of DegQ decreases the concentration of phosphorylated DegU, which leads to the de-repression of the srfA operon and ultimately to the stabilization of ComK. As a result, more cells reach the threshold concentration of ComK needed to activate the auto-regulatory loop at the comK promoter. In addition, we demonstrate that the activation of srfA transcription in undomesticated strains is transient, turning off abruptly as cells enter the stationary phase. Thus, the K-state and transformability are more transient and less frequently expressed in the undomesticated strains. This limitation is more extreme than appreciated from studies of domesticated strains. Selection has apparently limited both the frequency and the duration of the bistably expressed K-state in wild strains, likely because of the high cost of growth arrest associated with the K-state. Future modeling of K-state regulation and of the fitness advantages and costs of the K-state must take these features into account.
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Affiliation(s)
- Mathieu Miras
- Public Health Research Institute Center, New Jersey Medical School, Rutgers University, NewarkNJ, USA; Laboratoire de Microbiologie et Génétique Moléculaires, Université de ToulouseToulouse, France
| | - David Dubnau
- Public Health Research Institute Center, New Jersey Medical School, Rutgers University, Newark NJ, USA
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Kaspar J, Kim JN, Ahn SJ, Burne RA. An Essential Role for (p)ppGpp in the Integration of Stress Tolerance, Peptide Signaling, and Competence Development in Streptococcus mutans. Front Microbiol 2016; 7:1162. [PMID: 27516759 PMCID: PMC4963387 DOI: 10.3389/fmicb.2016.01162] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2016] [Accepted: 07/12/2016] [Indexed: 11/25/2022] Open
Abstract
The microbes that inhabit the human oral cavity are subjected to constant fluctuations in their environment. To overcome these challenges and gain a competitive advantage, oral streptococci employ numerous adaptive strategies, many of which appear to be intertwined with the development of genetic competence. Here, we demonstrate that the regulatory circuits that control development of competence in Streptococcus mutans, a primary etiological agent of human dental caries, are integrated with key stress tolerance pathways by the molecular alarmone (p)ppGpp. We first observed that the growth of a strain that does not produce (p)ppGpp (ΔrelAPQ, (p)ppGpp0) is not sensitive to growth inhibition by comXinducing peptide (XIP), unlike the wild-type strain UA159, even though XIP-dependent activation of the alternative sigma factor comX by the ComRS pathway is not impaired in the (p)ppGpp0 strain. Overexpression of a (p)ppGpp synthase gene (relP) in the (p)ppGpp0 mutant restored growth inhibition by XIP. We also demonstrate that exposure to micromolar concentrations of XIP elicited changes in (p)ppGpp accumulation in UA159. Loss of the RelA/SpoT homolog (RSH) enzyme, RelA, lead to higher basal levels of (p)ppGpp accumulation, but to decreased sensitivity to XIP and to decreases in comR promoter activity and ComX protein levels. By introducing single amino acid substitutions into the RelA enzyme, the hydrolase activity of the enzyme was shown to be crucial for full com gene induction and transformation by XIP. Finally, loss of relA resulted in phenotypic changes to ΔrcrR mutants, highlighted by restoration of transformation and ComX protein production in the otherwise non-transformable ΔrcrR-NP mutant. Thus, RelA activity and its influence on (p)ppGpp pools appears to modulate competence signaling and development through RcrRPQ and the peptide effectors encoded within rcrQ. Collectively, this study provides new insights into the molecular mechanisms that integrate intercellular communication with the physiological status of the cells and the regulation of key virulence-related phenotypes in S. mutans.
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Affiliation(s)
- Justin Kaspar
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
| | - Jeong N Kim
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
| | - Sang-Joon Ahn
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
| | - Robert A Burne
- Department of Oral Biology, College of Dentistry, University of Florida, Gainesville FL, USA
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Stationary-Phase Mutagenesis in Stressed Bacillus subtilis Cells Operates by Mfd-Dependent Mutagenic Pathways. Genes (Basel) 2016; 7:genes7070033. [PMID: 27399782 PMCID: PMC4962003 DOI: 10.3390/genes7070033] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2016] [Revised: 06/22/2016] [Accepted: 06/24/2016] [Indexed: 12/15/2022] Open
Abstract
In replication-limited cells of Bacillus subtilis, Mfd is mutagenic at highly transcribed regions, even in the absence of bulky DNA lesions. However, the mechanism leading to increased mutagenesis through Mfd remains currently unknown. Here, we report that Mfd may promote mutagenesis in nutritionally stressed B. subtilis cells by coordinating error-prone repair events mediated by UvrA, MutY and PolI. Using a point-mutated gene conferring leucine auxotrophy as a genetic marker, it was found that the absence of UvrA reduced the Leu+ revertants and that a second mutation in mfd reduced mutagenesis further. Moreover, the mfd and polA mutants presented low but similar reversion frequencies compared to the parental strain. These results suggest that Mfd promotes mutagenic events that required the participation of NER pathway and PolI. Remarkably, this Mfd-dependent mutagenic pathway was found to be epistatic onto MutY; however, whereas the MutY-dependent Leu+ reversions required Mfd, a direct interaction between these proteins was not apparent. In summary, our results support the concept that Mfd promotes mutagenesis in starved B. subtilis cells by coordinating both known and previously unknown Mfd-associated repair pathways. These mutagenic processes bias the production of genetic diversity towards highly transcribed regions in the genome.
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Yüksel M, Power JJ, Ribbe J, Volkmann T, Maier B. Fitness Trade-Offs in Competence Differentiation of Bacillus subtilis. Front Microbiol 2016; 7:888. [PMID: 27375604 PMCID: PMC4896167 DOI: 10.3389/fmicb.2016.00888] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Accepted: 05/25/2016] [Indexed: 11/15/2022] Open
Abstract
In the stationary phase, Bacillus subtilis differentiates stochastically and transiently into the state of competence for transformation (K-state). The latter is associated with growth arrest, and it is unclear how the ability to develop competence is stably maintained, despite its cost. To quantify the effect differentiation has on the competitive fitness of B. subtilis, we characterized the competition dynamics between strains with different probabilities of entering the K-state. The relative fitness decreased with increasing differentiation probability both during the stationary phase and during outgrowth. When exposed to antibiotics inhibiting cell wall synthesis, transcription, and translation, cells that differentiated into the K-state showed a selective advantage compared to differentiation-deficient bacteria; this benefit did not require transformation. Although beneficial, the K-state was not induced by sub-MIC concentrations of antibiotics. Increasing the differentiation probability beyond the wt level did not significantly affect the competition dynamics with transient antibiotic exposure. We conclude that the competition dynamics are very sensitive to the fraction of competent cells under benign conditions but less sensitive during antibiotic exposure, supporting the picture of stochastic differentiation as a fitness trade-off.
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Affiliation(s)
- Melih Yüksel
- Department of Physics, University of Cologne Köln, Germany
| | | | - Jan Ribbe
- Department of Physics, University of Cologne Köln, Germany
| | | | - Berenike Maier
- Department of Physics, University of Cologne Köln, Germany
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Zaccaria E, Wells JM, van Baarlen P. Metabolic Context of the Competence-Induced Checkpoint for Cell Replication in Streptococcus suis. PLoS One 2016; 11:e0153571. [PMID: 27149631 PMCID: PMC4858297 DOI: 10.1371/journal.pone.0153571] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Accepted: 03/31/2016] [Indexed: 11/19/2022] Open
Abstract
Natural genetic transformation is a transient, rapidly progressing energy-consuming process characterized by expression of the transformasome and competence-associated regulatory genes. This transient state is tightly controlled to avoid potentially adverse effects of genetic recombination on genome integrity during cell division. We investigated the global response of Streptococcus suis to exposure to the SigX competence-inducing peptide (XIP), and thus to the activation of the competence machinery, using time series analysis together with PCA analysis, gene clustering followed by heatmap visualisation, and GO enrichment analysis. We explored the possible regulatory link between metabolism and competence, and predicted the physiological adaptation of S. suis during competence induction, progression and exit using transcriptome analysis. We showed that competence development is associated with a suppression of basal metabolism, which may have consequences for the microbe's resilience to fluctuations in the environment, as competence is costly in terms of use of energy and protein translation. Furthermore our data suggest that several basal metabolic pathways are incompatible with activation of competence in S. suis. This study also showed that targeting specific pathways during the development of competence, might render S. suis more vulnerable toward novel antibiotic therapies.
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Affiliation(s)
- Edoardo Zaccaria
- Host-Microbe Interactomics, Animal Sciences, Wageningen University, Wageningen, The Netherlands
| | - Jerry M. Wells
- Host-Microbe Interactomics, Animal Sciences, Wageningen University, Wageningen, The Netherlands
| | - Peter van Baarlen
- Host-Microbe Interactomics, Animal Sciences, Wageningen University, Wageningen, The Netherlands
- * E-mail:
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30
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Juan PA, Attaiech L, Charpentier X. Natural transformation occurs independently of the essential actin-like MreB cytoskeleton in Legionella pneumophila. Sci Rep 2015; 5:16033. [PMID: 26526572 PMCID: PMC4630621 DOI: 10.1038/srep16033] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/08/2015] [Indexed: 11/10/2022] Open
Abstract
Natural transformation is the process by which bacteria can actively take up and integrate exogenous DNA thereby providing a source of genetic diversity. Under specific growth conditions the coordinated expression of several genes – a situation referred to as “competence” – allows bacteria to assemble a highly processive and dedicated system that can import high molecular weight DNA. Within the cell these large imported DNA molecules are protected from degradation and brought to the chromosome for recombination. Here, we report elevated expression of mreB during competence in the Gram-negative pathogen Legionella pneumophila. Interestingly a similar observation had previously been reported in the distantly-related Gram-positive organism Bacillus subtilis. MreB is often viewed as the bacterial actin homolog contributing to bacterial morphogenesis by coordinating peptidoglycan-synthesising complexes. In addition MreB is increasingly found to be involved in a growing number of processes including chromosome segregation and motor-driven motility. Using genetic and pharmacological approaches, we examined the possible role of MreB during natural transformation in L. pneumophila. Our data show that natural transformation does not require MreB dynamics and exclude a direct role of MreB filaments in the transport of foreign DNA and its recombination in the chromosome.
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Affiliation(s)
- Pierre-Alexandre Juan
- CNRS UMR5240 MAP, Villeurbanne, France.,Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Laetitia Attaiech
- CNRS UMR5240 MAP, Villeurbanne, France.,Université Claude Bernard Lyon 1, Villeurbanne, France
| | - Xavier Charpentier
- CNRS UMR5240 MAP, Villeurbanne, France.,Université Claude Bernard Lyon 1, Villeurbanne, France
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Wang N, Jiang J, Li X, Tan H, Zheng J, Chen G, Jia Z. Molecular Dynamics Simulation Studies of dTTP Binding and Catalysis Mediated by YhdE Dimerization. PLoS One 2015; 10:e0134879. [PMID: 26252214 PMCID: PMC4529217 DOI: 10.1371/journal.pone.0134879] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Accepted: 07/14/2015] [Indexed: 11/18/2022] Open
Abstract
YhdE is a Maf-like (multicopy associated filamentation) protein that primarily acts as dTTPase to hydrolyze dTTP into dTMP and two phosphate molecules in cell metabolism pathway. Two crystal structures of YhdE have been previously determined, representing the open and closed active site conformations, respectively. Based on the structures, we have carried out molecular dynamics simulations and free energy calculations to investigate dTTP binding to and hydrolysis by YhdE. Our results suggest that YhdE closed state is structurally more compact than its open state at room temperature. YhdE open state is a favorable conformation for dTTP binding and closed state is a structurally favorable conformation for catalytic reaction. This observation is supported by the structure of YhdE homolog in complex with a nucleotide analog. Free energy calculations reveal that YhdE dimerization occurs preferentially in dTTP binding and is favorable for successive cooperative reaction. The key residues R11, R12 and K80, are found to contribute to the substrate stabilization. Further, YhdE dimerization and binding of dTTP induce the cooperative effect through a direct allosteric communication network in YhdE from the dTTP binding sites in the catalytic center to the intermolecular β-strand in YhdE dimer.
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Affiliation(s)
- Nan Wang
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Jiahong Jiang
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Xichen Li
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Hongwei Tan
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Jimin Zheng
- College of Chemistry, Beijing Normal University, Beijing, China
- * E-mail: (JMZ); (ZCJ)
| | - Guangju Chen
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Zongchao Jia
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
- * E-mail: (JMZ); (ZCJ)
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32
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Fontaine L, Wahl A, Fléchard M, Mignolet J, Hols P. Regulation of competence for natural transformation in streptococci. INFECTION GENETICS AND EVOLUTION 2015; 33:343-60. [DOI: 10.1016/j.meegid.2014.09.010] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 08/28/2014] [Accepted: 09/07/2014] [Indexed: 02/02/2023]
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33
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Gamba P, Jonker MJ, Hamoen LW. A Novel Feedback Loop That Controls Bimodal Expression of Genetic Competence. PLoS Genet 2015; 11:e1005047. [PMID: 26110430 PMCID: PMC4482431 DOI: 10.1371/journal.pgen.1005047] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Accepted: 02/01/2015] [Indexed: 01/25/2023] Open
Abstract
Gene expression can be highly heterogeneous in isogenic cell populations. An extreme type of heterogeneity is the so-called bistable or bimodal expression, whereby a cell can differentiate into two alternative expression states. Stochastic fluctuations of protein levels, also referred to as noise, provide the necessary source of heterogeneity that must be amplified by specific genetic circuits in order to obtain a bimodal response. A classical model of bimodal differentiation is the activation of genetic competence in Bacillus subtilis. The competence transcription factor ComK activates transcription of its own gene, and an intricate regulatory network controls the switch to competence and ensures its reversibility. However, it is noise in ComK expression that determines which cells activate the ComK autostimulatory loop and become competent for genetic transformation. Despite its important role in bimodal gene expression, noise remains difficult to investigate due to its inherent stochastic nature. We adapted an artificial autostimulatory loop that bypasses all known ComK regulators to screen for possible factors that affect noise. This led to the identification of a novel protein Kre (YkyB) that controls the bimodal regulation of ComK. Interestingly, Kre appears to modulate the induction of ComK by affecting the stability of comK mRNA. The protein influences the expression of many genes, however, Kre is only found in bacteria that contain a ComK homologue and, importantly, kre expression itself is downregulated by ComK. The evolutionary significance of this new feedback loop for the reduction of transcriptional noise in comK expression is discussed. Our findings show the importance of mRNA stability in bimodal regulation, a factor that requires more attention when studying and modelling this non-deterministic developmental mechanism. Gene expression can be highly heterogeneous in clonal cell populations. An extreme type of heterogeneity is the so-called bistable or bimodal expression, whereby a cell can differentiate into two alternative expression states, and consequently a population will be composed of cells that are ‘ON’ and cells that are ‘OFF’. Stochastic fluctuations of protein levels, also referred to as noise, provide the necessary source of heterogeneity that must be amplified by autostimulatory feedback regulation to obtain the bimodal response. A classical model of bistable differentiation is the development of genetic competence in Bacillus subtilis. Noise in expression of the transcription factor ComK ultimately determines the fraction of cells that enter the competent state. Due to its intrinsic random nature, noise is difficult to investigate. We adapted an artificial autostimulatory loop that bypasses all known ComK regulators, to screen for possible factors that affect noise in the bimodal regulation of ComK. This led to the discovery of Kre, a novel factor that controls the bimodal expression of ComK. Kre appears to affect the stability of comK mRNA. Interestingly, ComK itself represses the expression of kre, adding a new double negative feedback loop to the intricate ComK regulation circuit. Our data emphasize that mRNA stability is an important factor in bimodal regulation.
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Affiliation(s)
- Pamela Gamba
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- * E-mail: (PG); (LWH)
| | - Martijs J. Jonker
- MicroArray Department and Integrative Bioinformatics Unit, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
| | - Leendert W. Hamoen
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University, Newcastle upon Tyne, United Kingdom
- Bacterial Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam, Amsterdam, The Netherlands
- * E-mail: (PG); (LWH)
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MreB-Dependent Inhibition of Cell Elongation during the Escape from Competence in Bacillus subtilis. PLoS Genet 2015; 11:e1005299. [PMID: 26091431 PMCID: PMC4474612 DOI: 10.1371/journal.pgen.1005299] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Accepted: 05/26/2015] [Indexed: 02/02/2023] Open
Abstract
During bacterial exponential growth, the morphogenetic actin-like MreB proteins form membrane-associated assemblies that move processively following trajectories perpendicular to the long axis of the cell. Such MreB structures are thought to scaffold and restrict the movement of peptidoglycan synthesizing machineries, thereby coordinating sidewall elongation. In Bacillus subtilis, this function is performed by the redundant action of three MreB isoforms, namely MreB, Mbl and MreBH. mreB and mbl are highly transcribed from vegetative promoters. We have found that their expression is maximal at the end of exponential phase, and rapidly decreases to a low basal level upon entering stationary phase. However, in cells developing genetic competence, a stationary phase physiological adaptation, expression of mreB was specifically reactivated by the central competence regulator ComK. In competent cells, MreB was found in complex with several competence proteins by in vitro pull-down assays. In addition, it co-localized with the polar clusters formed by the late competence peripheral protein ComGA, in a ComGA-dependent manner. ComGA has been shown to be essential for the inhibition of cell elongation characteristic of cells escaping the competence state. We show here that the pathway controlling this elongation inhibition also involves MreB. Our findings suggest that ComGA sequesters MreB to prevent cell elongation and therefore the escape from competence. In bacterial cells, like in their eukaryotic counterparts, precise spatiotemporal localization of proteins is critical for their cellular function. This study shows that the expression and the localization of the bacterial actin-like MreB protein are growth phase-dependent. During exponential growth, we previously showed that MreB, together with other morphogenetic factors, forms discrete assemblies that move in a directed manner along peripheral tracks. Here, we demonstrate that in cells that develop genetic competence during stationary phase, transcription of mreB is specifically activated and MreB relocalizes to the cell poles. Our findings suggest a model in which MreB sequestration by the late competence protein ComGA prevents cell elongation during the escape from competence.
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35
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Hahn J, Tanner AW, Carabetta VJ, Cristea IM, Dubnau D. ComGA-RelA interaction and persistence in the Bacillus subtilis K-state. Mol Microbiol 2015; 97:454-71. [PMID: 25899641 DOI: 10.1111/mmi.13040] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/19/2015] [Indexed: 01/17/2023]
Abstract
The bistably expressed K-state of Bacillus subtilis is characterized by two distinct features; transformability and arrested growth when K-state cells are exposed to fresh medium. The arrest is manifested by a failure to assemble replisomes and by decreased rates of cell growth and rRNA synthesis. These phenotypes are all partially explained by the presence of the AAA(+) protein ComGA, which is also required for the binding of transforming DNA to the cell surface and for the assembly of the transformation pilus that mediates DNA transport. We have discovered that ComGA interacts with RelA and that the ComGA-dependent inhibition of rRNA synthesis is largely bypassed in strains that cannot synthesize the alarmone (p)ppGpp. We propose that the interaction of ComGA with RelA prevents the hydrolysis of (p)ppGpp in K-state cells, which are thus trapped in a non-growing state until ComGA is degraded. We show that some K-state cells exhibit tolerance to antibiotics, a form of type 1 persistence, and we propose that the bistable expression of both transformability and the growth arrest are bet-hedging adaptations that improve fitness in the face of varying environments, such as those presumably encountered by B. subtilis in the soil.
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Affiliation(s)
- Jeanette Hahn
- Public Health Research Institute Center of New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
| | - Andrew W Tanner
- Public Health Research Institute Center of New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
| | - Valerie J Carabetta
- Public Health Research Institute Center of New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
| | - Ileana M Cristea
- Department of Molecular Biology, Princeton University, Princeton, NJ, 08544, USA
| | - David Dubnau
- Public Health Research Institute Center of New Jersey Medical School, Rutgers University, 225 Warren Street, Newark, NJ, 07103, USA
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36
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FtsZ filament capping by MciZ, a developmental regulator of bacterial division. Proc Natl Acad Sci U S A 2015; 112:E2130-8. [PMID: 25848052 DOI: 10.1073/pnas.1414242112] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Cytoskeletal structures are dynamically remodeled with the aid of regulatory proteins. FtsZ (filamentation temperature-sensitive Z) is the bacterial homolog of tubulin that polymerizes into rings localized to cell-division sites, and the constriction of these rings drives cytokinesis. Here we investigate the mechanism by which the Bacillus subtilis cell-division inhibitor, MciZ (mother cell inhibitor of FtsZ), blocks assembly of FtsZ. The X-ray crystal structure reveals that MciZ binds to the C-terminal polymerization interface of FtsZ, the equivalent of the minus end of tubulin. Using in vivo and in vitro assays and microscopy, we show that MciZ, at substoichiometric levels to FtsZ, causes shortening of protofilaments and blocks the assembly of higher-order FtsZ structures. The findings demonstrate an unanticipated capping-based regulatory mechanism for FtsZ.
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37
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Jin J, Wu R, Zhu J, Yang S, Lei Z, Wang N, Singh VK, Zheng J, Jia Z. Insights into the cellular function of YhdE, a nucleotide pyrophosphatase from Escherichia coli. PLoS One 2015; 10:e0117823. [PMID: 25658941 PMCID: PMC4319933 DOI: 10.1371/journal.pone.0117823] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2014] [Accepted: 01/02/2015] [Indexed: 11/19/2022] Open
Abstract
YhdE, a Maf-like protein in Escherichia coli, exhibits nucleotide pyrophosphatase (PPase) activity, yet its cellular function remains unknown. Here, we characterized the PPase activity of YhdE on dTTP, UTP and TTP and determined two crystal structures of YhdE, revealing ‘closed’ and ‘open’ conformations of an adaptive active site. Our functional studies demonstrated that YhdE retards cell growth by prolonging the lag and log phases, particularly under stress conditions. Morphology studies showed that yhdE-knockout cells transformed the normal rod shape of wild-type cells to a more spherical form, and the cell wall appeared to become more flexible. In contrast, YhdE overexpression resulted in filamentous cells. This study reveals the previously unknown involvement of YhdE in cell growth inhibition under stress conditions, cell-division arrest and cell-shape maintenance, highlighting YhdE’s important role in E. coli cell-cycle checkpoints.
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Affiliation(s)
- Jin Jin
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Ruijuan Wu
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Jia Zhu
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Shaoyuan Yang
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Zhen Lei
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Nan Wang
- College of Chemistry, Beijing Normal University, Beijing, China
| | - Vinay K. Singh
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
| | - Jimin Zheng
- College of Chemistry, Beijing Normal University, Beijing, China
- * E-mail: (JZ); (ZJ)
| | - Zongchao Jia
- College of Chemistry, Beijing Normal University, Beijing, China
- Department of Biomedical and Molecular Sciences, Queen’s University, Kingston, Ontario, Canada
- * E-mail: (JZ); (ZJ)
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38
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Muschiol S, Balaban M, Normark S, Henriques-Normark B. Uptake of extracellular DNA: competence induced pili in natural transformation of Streptococcus pneumoniae. Bioessays 2015; 37:426-35. [PMID: 25640084 PMCID: PMC4405041 DOI: 10.1002/bies.201400125] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Transport of DNA across bacterial membranes involves complex DNA uptake systems. In Gram-positive bacteria, the DNA uptake machinery shares fundamental similarities with type IV pili and type II secretion systems. Although dedicated pilus structures, such as type IV pili in Gram-negative bacteria, are necessary for efficient DNA uptake, the role of similar structures in Gram-positive bacteria is just beginning to emerge. Recently two essentially very different pilus structures composed of the same major pilin protein ComGC were proposed to be involved in transformation of the Gram-positive bacterium Streptococcus pneumoniae – one is a long, thin, type IV pilus-like fiber with DNA binding capacity and the other one is a pilus structure that was thicker, much shorter and not able to bind DNA. Here we discuss how competence induced pili, either by pilus retraction or by a transient pilus-related opening in the cell wall, may mediate DNA uptake in S. pneumoniae.
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Affiliation(s)
- Sandra Muschiol
- Department of Microbiology, Tumor and Cell Biology, Karolinska Institutet, Stockholm, Sweden; Department of Laboratory Medicine, Division of Clinical Microbiology, Karolinska University Hospital, Stockholm, Sweden
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Sieger B, Bramkamp M. Interaction sites of DivIVA and RodA from Corynebacterium glutamicum. Front Microbiol 2015; 5:738. [PMID: 25709601 PMCID: PMC4285798 DOI: 10.3389/fmicb.2014.00738] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Accepted: 12/05/2014] [Indexed: 11/29/2022] Open
Abstract
Elongation growth in actinobacteria is localized at the cell poles. This is in contrast to many classical model organisms where insertion of new cell wall material is localized around the lateral site. We previously described a role of RodA from Corynebacterium glutamicum in apical cell growth and morphogenesis. Deletion of rodA had drastic effects on morphology and growth, likely a result from misregulation of penicillin-binding proteins and cell wall precursor delivery. We identified the interaction of RodA with the polar scaffold protein DivIVA, thus explaining subcellular localization of RodA to the cell poles. In this study, we describe this interaction in detail and map the interaction sites of DivIVA and RodA. A single amino acid residue in the N-terminal domain of DivIVA was found to be crucial for the interaction with RodA. The interaction site of RodA was mapped to its cytoplasmic, C-terminal domain, in a region encompassing the last 10 amino acids (AAs). Deletion of these 10 AAs significantly decreased the interaction efficiency with DivIVA. Our results corroborate the interaction of DivIVA and RodA, underscoring the important role of DivIVA as a spatial organizer of the elongation machinery in Corynebacterineae.
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Affiliation(s)
- Boris Sieger
- Biocenter - Ludwig-Maximilians-University Munich Munich, Germany
| | - Marc Bramkamp
- Biocenter - Ludwig-Maximilians-University Munich Munich, Germany
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Jakobs M, Meinhardt F. What renders Bacilli genetically competent? A gaze beyond the model organism. Appl Microbiol Biotechnol 2014; 99:1557-70. [DOI: 10.1007/s00253-014-6316-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 12/08/2014] [Accepted: 12/09/2014] [Indexed: 12/20/2022]
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Kaval KG, Rismondo J, Halbedel S. A function of DivIVA in Listeria monocytogenes division site selection. Mol Microbiol 2014; 94:637-54. [PMID: 25185533 DOI: 10.1111/mmi.12784] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/02/2014] [Indexed: 11/29/2022]
Abstract
The cell division protein DivIVA influences protein transport via the accessory SecA2 secretion route in Listeria monocytogenes. In contrast, DivIVA from the closely related bacterium Bacillus subtilis contributes to division site selection via the MinCDJ system. However, no classical min phenotype, i.e. filamentation and minicell production was observed with a listerial ΔdivIVA mutant. This has prompted the speculation that division site selection is DivIVA-independent in L. monocytogenes. We addressed this question with genetic, cytological and bacterial two-hybrid experiments and the data obtained correct this view. DivIVA not only binds to MinJ but also directly interacts with MinD. Experiments with fluorescently tagged proteins showed that localization of MinC and MinD was clearly DivIVA-dependent, whereas localization of MinJ was not. An impact of DivIVA on cell division was confirmed by careful comparisons of cell size distributions of divIVA and secA2 mutants. Gene deletion studies and epistasis experiments consistently reinforced these findings, and also revealed that MinJ must have a DivIVA-independent function. The frequency of minicell formation is low in L. monocytogenes min mutants. However, since listerial minicells might be useful as carriers for the introduction of therapeutic compounds into eukaryotic cells, we present a strategy how minicell frequency can be increased.
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Affiliation(s)
- Karan Gautam Kaval
- FG11 Division of Enteropathogenic Bacteria and Legionella, Robert Koch Institute, Burgstrasse 37, 38855, Wernigerode, Germany
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Abstract
Daptomycin is a lipopeptide antimicrobial with in vitro bactericidal activity against Gram-positive bacteria that was first approved for clinical use in 2004 in the United States. Since this time, significant data have emerged regarding the use of daptomycin for the treatment of serious infections, such as bacteremia and endocarditis, caused by Gram-positive pathogens. However, there are also increasing reports of daptomycin nonsusceptibility, in Staphylococcus aureus and, in particular, Enterococcus faecium and Enterococcus faecalis. Such nonsusceptibility is largely in the context of prolonged treatment courses and infections with high bacterial burdens, but it may occur in the absence of prior daptomycin exposure. Nonsusceptibility in both S. aureus and Enterococcus is mediated by adaptations to cell wall homeostasis and membrane phospholipid metabolism. This review summarizes the data on daptomycin, including daptomycin's unique mode of action and spectrum of activity and mechanisms for nonsusceptibility in key pathogens, including S. aureus, E. faecium, and E. faecalis. The challenges faced by the clinical laboratory in obtaining accurate susceptibility results and reporting daptomycin MICs are also discussed.
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Haeusser DP, Hoashi M, Weaver A, Brown N, Pan J, Sawitzke JA, Thomason LC, Court DL, Margolin W. The Kil peptide of bacteriophage λ blocks Escherichia coli cytokinesis via ZipA-dependent inhibition of FtsZ assembly. PLoS Genet 2014; 10:e1004217. [PMID: 24651041 PMCID: PMC3961180 DOI: 10.1371/journal.pgen.1004217] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 01/17/2014] [Indexed: 11/19/2022] Open
Abstract
Assembly of the essential, tubulin-like FtsZ protein into a ring-shaped structure at the nascent division site determines the timing and position of cytokinesis in most bacteria and serves as a scaffold for recruitment of the cell division machinery. Here we report that expression of bacteriophage λ kil, either from a resident phage or from a plasmid, induces filamentation of Escherichia coli cells by rapid inhibition of FtsZ ring formation. Mutant alleles of ftsZ resistant to the Kil protein map to the FtsZ polymer subunit interface, stabilize FtsZ ring assembly, and confer increased resistance to endogenous FtsZ inhibitors, consistent with Kil inhibiting FtsZ assembly. Cells with the normally essential cell division gene zipA deleted (in a modified background) display normal FtsZ rings after kil expression, suggesting that ZipA is required for Kil-mediated inhibition of FtsZ rings in vivo. In support of this model, point mutations in the C-terminal FtsZ-interaction domain of ZipA abrogate Kil activity without discernibly altering FtsZ-ZipA interactions. An affinity-tagged-Kil derivative interacts with both FtsZ and ZipA, and inhibits sedimentation of FtsZ filament bundles in vitro. Together, these data inspire a model in which Kil interacts with FtsZ and ZipA in the cell to prevent FtsZ assembly into a coherent, division-competent ring structure. Phage growth assays show that kil+ phage lyse ∼30% later than kil mutant phage, suggesting that Kil delays lysis, perhaps via its interaction with FtsZ and ZipA.
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Affiliation(s)
- Daniel P. Haeusser
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas, United States of America
| | - Marina Hoashi
- National Cancer Institute at Frederick, Gene Regulation and Chromosome Biology Laboratory, Frederick, Maryland, United States of America
| | - Anna Weaver
- National Cancer Institute at Frederick, Gene Regulation and Chromosome Biology Laboratory, Frederick, Maryland, United States of America
| | - Nathan Brown
- National Cancer Institute at Frederick, Gene Regulation and Chromosome Biology Laboratory, Frederick, Maryland, United States of America
| | - James Pan
- National Cancer Institute at Frederick, Gene Regulation and Chromosome Biology Laboratory, Frederick, Maryland, United States of America
| | - James A. Sawitzke
- National Cancer Institute at Frederick, Gene Regulation and Chromosome Biology Laboratory, Frederick, Maryland, United States of America
| | - Lynn C. Thomason
- Frederick National Laboratory for Cancer Research, Leidos Biomedical, Inc., Gene Regulation and Chromosome Biology Laboratory, Frederick, Maryland, United States of America
| | - Donald L. Court
- National Cancer Institute at Frederick, Gene Regulation and Chromosome Biology Laboratory, Frederick, Maryland, United States of America
| | - William Margolin
- Department of Microbiology and Molecular Genetics, University of Texas Medical School at Houston, Houston, Texas, United States of America
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Halbedel S, Kawai M, Breitling R, Hamoen LW. SecA is required for membrane targeting of the cell division protein DivIVA in vivo. Front Microbiol 2014; 5:58. [PMID: 24592260 PMCID: PMC3924036 DOI: 10.3389/fmicb.2014.00058] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Accepted: 01/29/2014] [Indexed: 11/13/2022] Open
Abstract
The conserved protein DivIVA is involved in different morphogenetic processes in Gram-positive bacteria. In Bacillus subtilis, the protein localizes to the cell division site and cell poles, and functions as a scaffold for proteins that regulate division site selection, and for proteins that are required for sporulation. To identify other proteins that bind to DivIVA, we performed an in vivo cross-linking experiment. A possible candidate that emerged was the secretion motor ATPase SecA. SecA mutants have been described that inhibit sporulation, and since DivIVA is necessary for sporulation, we examined the localization of DivIVA in these mutants. Surprisingly, DivIVA was delocalized, suggesting that SecA is required for DivIVA targeting. To further corroborate this, we performed SecA depletion and inhibition experiments, which provided further indications that DivIVA localization depends on SecA. Cell fractionation experiments showed that SecA is important for binding of DivIVA to the cell membrane. This was unexpected since DivIVA does not contain a signal sequence, and is able to bind to artificial lipid membranes in vitro without support of other proteins. SecA is required for protein secretion and membrane insertion, and therefore its role in DivIVA localization is likely indirect. Possible alternative roles of SecA in DivIVA folding and/or targeting are discussed.
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Affiliation(s)
- Sven Halbedel
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University Newcastle upon Tyne, UK ; FG11 Division of Enteropathogenic bacteria and Legionella, Robert Koch Institute Wernigerode, Germany
| | - Maki Kawai
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University Newcastle upon Tyne, UK
| | - Reinhard Breitling
- Institut für Molekularbiologie, Friedrich-Schiller-Universität Jena, Germany
| | - Leendert W Hamoen
- Centre for Bacterial Cell Biology, Institute for Cell and Molecular Biosciences, Newcastle University Newcastle upon Tyne, UK ; Bacterial Cell Biology, Swammerdam Institute for Life Sciences, University of Amsterdam Amsterdam, Netherlands
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Abstract
It is now well appreciated that bacterial cells are highly organized, which is far from the initial concept that they are merely bags of randomly distributed macromolecules and chemicals. Central to their spatial organization is the precise positioning of certain proteins in subcellular domains of the cell. In particular, the cell poles - the ends of rod-shaped cells - constitute important platforms for cellular regulation that underlie processes as essential as cell cycle progression, cellular differentiation, virulence, chemotaxis and growth of appendages. Thus, understanding how the polar localization of specific proteins is achieved and regulated is a crucial question in bacterial cell biology. Often, polarly localized proteins are recruited to the poles through their interaction with other proteins or protein complexes that were already located there, in a so-called diffusion-and-capture mechanism. Bacteria are also starting to reveal their secrets on how the initial pole 'recognition' can occur and how this event can be regulated to generate dynamic, reproducible patterns in time (for example, during the cell cycle) and space (for example, at a specific cell pole). Here, we review the major mechanisms that have been described in the literature, with an emphasis on the self-organizing principles. We also present regulation strategies adopted by bacterial cells to obtain complex spatiotemporal patterns of protein localization.
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Affiliation(s)
- Géraldine Laloux
- de Duve Institute, Université Catholique de Louvain, B-1200 Brussels, Belgium
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Tchigvintsev A, Tchigvintsev D, Flick R, Popovic A, Dong A, Xu X, Brown G, Lu W, Wu H, Cui H, Dombrowski L, Joo JC, Beloglazova N, Min J, Savchenko A, Caudy AA, Rabinowitz JD, Murzin AG, Yakunin AF. Biochemical and structural studies of conserved Maf proteins revealed nucleotide pyrophosphatases with a preference for modified nucleotides. ACTA ACUST UNITED AC 2013; 20:1386-98. [PMID: 24210219 PMCID: PMC3899018 DOI: 10.1016/j.chembiol.2013.09.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2013] [Revised: 09/06/2013] [Accepted: 09/13/2013] [Indexed: 11/17/2022]
Abstract
Maf (for multicopy associated filamentation) proteins represent a large family of conserved proteins implicated in cell division arrest but whose biochemical activity remains unknown. Here, we show that the prokaryotic and eukaryotic Maf proteins exhibit nucleotide pyrophosphatase activity against 5-methyl-UTP, pseudo-UTP, 5-methyl-CTP, and 7-methyl-GTP, which represent the most abundant modified bases in all organisms, as well as against canonical nucleotides dTTP, UTP, and CTP. Overexpression of the Maf protein YhdE in E. coli cells increased intracellular levels of dTMP and UMP, confirming that dTTP and UTP are the in vivo substrates of this protein. Crystal structures and site-directed mutagenesis of Maf proteins revealed the determinants of their activity and substrate specificity. Thus, pyrophosphatase activity of Maf proteins toward canonical and modified nucleotides might provide the molecular mechanism for a dual role of these proteins in cell division arrest and house cleaning. Maf proteins represent a family of nucleoside triphosphate pyrophosphatases Maf proteins hydrolyze the canonical nucleotides dTTP, UTP, and CTP Maf proteins are also active against m5UTP, m5CTP, pseudo-UTP, and m7GTP Maf structures reveal the molecular mechanisms of their substrate selectivity
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Affiliation(s)
- Anatoli Tchigvintsev
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON M5S 3E5, Canada
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Lin L, Thanbichler M. Nucleotide-independent cytoskeletal scaffolds in bacteria. Cytoskeleton (Hoboken) 2013; 70:409-23. [PMID: 23852773 DOI: 10.1002/cm.21126] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2013] [Revised: 06/28/2013] [Accepted: 07/03/2013] [Indexed: 11/11/2022]
Abstract
Bacteria possess a diverse set of cytoskeletal proteins that mediate key cellular processes such as morphogenesis, cell division, DNA segregation, and motility. Similar to eukaryotic actin or tubulin, many of them require nucleotide binding and hydrolysis for proper polymerization and function. However, there is also a growing number of bacterial cytoskeletal elements that assemble in a nucleotide-independent manner, including intermediate filament-like structures as well several classes of bacteria-specific polymers. The members of this group form stable scaffolds that have architectural roles or act as localization factors recruiting other proteins to distinct positions within the cell. Here, we highlight the elements that constitute the nucleotide-independent cytoskeleton of bacteria and discuss their biological functions in different species.
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Affiliation(s)
- Lin Lin
- Max Planck Research Group "Prokaryotic Cell Biology", Max Planck Institute for Terrestrial Microbiology, Marburg, Germany; Faculty of Biology, Philipps-Universität, Marburg, Germany
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48
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Abstract
DivIVA proteins are curvature-sensitive membrane binding proteins that recruit other proteins to the poles and the division septum. They consist of a conserved N-terminal lipid binding domain fused to a less conserved C-terminal domain. DivIVA homologues interact with different proteins involved in cell division, chromosome segregation, genetic competence, or cell wall synthesis. It is unknown how DivIVA interacts with these proteins, and we used the interaction of Bacillus subtilis DivIVA with MinJ and RacA to investigate this. MinJ is a transmembrane protein controlling division site selection, and the DNA-binding protein RacA is crucial for chromosome segregation during sporulation. Initial bacterial two-hybrid experiments revealed that the C terminus of DivIVA appears to be important for recruiting both proteins. However, the interpretation of these results is limited since it appeared that C-terminal truncations also interfere with DivIVA oligomerization. Therefore, a chimera approach was followed, making use of the fact that Listeria monocytogenes DivIVA shows normal polar localization but is not biologically active when expressed in B. subtilis. Complementation experiments with different chimeras of B. subtilis and L. monocytogenes DivIVA suggest that MinJ and RacA bind to separate DivIVA domains. Fluorescence microscopy of green fluorescent protein-tagged RacA and MinJ corroborated this conclusion and suggests that MinJ recruitment operates via the N-terminal lipid binding domain, whereas RacA interacts with the C-terminal domain. We speculate that this difference is related to the cellular compartments in which MinJ and RacA are active: the cell membrane and the cytoplasm, respectively.
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RefZ facilitates the switch from medial to polar division during spore formation in Bacillus subtilis. J Bacteriol 2012; 194:4608-18. [PMID: 22730127 DOI: 10.1128/jb.00378-12] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
During sporulation, Bacillus subtilis redeploys the division protein FtsZ from midcell to the cell poles, ultimately generating an asymmetric septum. Here, we describe a sporulation-induced protein, RefZ, that facilitates the switch from a medial to a polar FtsZ ring placement. The artificial expression of RefZ during vegetative growth converts FtsZ rings into FtsZ spirals, arcs, and foci, leading to filamentation and lysis. Mutations in FtsZ specifically suppress RefZ-dependent division inhibition, suggesting that RefZ may target FtsZ. During sporulation, cells lacking RefZ are delayed in polar FtsZ ring formation, spending more time in the medial and transition stages of FtsZ ring assembly. A RefZ-green fluorescent protein (GFP) fusion localizes in weak polar foci at the onset of sporulation and as a brighter midcell focus at the time of polar division. RefZ has a TetR DNA binding motif, and point mutations in the putative recognition helix disrupt focus formation and abrogate cell division inhibition. Finally, chromatin immunoprecipitation assays identified sites of RefZ enrichment in the origin region and near the terminus. Collectively, these data support a model in which RefZ helps promote the switch from medial to polar division and is guided by the organization of the chromosome. Models in which RefZ acts as an activator of FtsZ ring assembly near the cell poles or as an inhibitor of the transient medial ring at midcell are discussed.
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50
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Modell JW, Hopkins AC, Laub MT. A DNA damage checkpoint in Caulobacter crescentus inhibits cell division through a direct interaction with FtsW. Genes Dev 2011; 25:1328-43. [PMID: 21685367 DOI: 10.1101/gad.2038911] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
Following DNA damage, cells typically delay cell cycle progression and inhibit cell division until their chromosomes have been repaired. The bacterial checkpoint systems responsible for these DNA damage responses are incompletely understood. Here, we show that Caulobacter crescentus responds to DNA damage by coordinately inducing an SOS regulon and inhibiting the master regulator CtrA. Included in the SOS regulon is sidA (SOS-induced inhibitor of cell division A), a membrane protein of only 29 amino acids that helps to delay cell division following DNA damage, but is dispensable in undamaged cells. SidA is sufficient, when overproduced, to block cell division. However, unlike many other regulators of bacterial cell division, SidA does not directly disrupt the assembly or stability of the cytokinetic ring protein FtsZ, nor does it affect the recruitment of other components of the cell division machinery. Instead, we provide evidence that SidA inhibits division by binding directly to FtsW to prevent the final constriction of the cytokinetic ring.
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Affiliation(s)
- Joshua W Modell
- Department of Biology, Massachusetts Institute of Technology, Cambridge, USA
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