1
|
Sass TH, Lovett ST. The DNA damage response of Escherichia coli, revisited: Differential gene expression after replication inhibition. Proc Natl Acad Sci U S A 2024; 121:e2407832121. [PMID: 38935560 PMCID: PMC11228462 DOI: 10.1073/pnas.2407832121] [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: 04/19/2024] [Accepted: 05/29/2024] [Indexed: 06/29/2024] Open
Abstract
In 1967, in this journal, Evelyn Witkin proposed the existence of a coordinated DNA damage response in Escherichia coli, which later came to be called the "SOS response." We revisited this response using the replication inhibitor azidothymidine (AZT) and RNA-Seq analysis and identified several features. We confirm the induction of classic Save our ship (SOS) loci and identify several genes, including many of the pyrimidine pathway, that have not been previously demonstrated to be DNA damage-inducible. Despite a strong dependence on LexA, these genes lack LexA boxes and their regulation by LexA is likely to be indirect via unknown factors. We show that the transcription factor "stringent starvation protein" SspA is as important as LexA in the regulation of AZT-induced genes and that the genes activated by SspA change dramatically after AZT exposure. Our experiments identify additional LexA-independent DNA damage inducible genes, including 22 small RNA genes, some of which appear to activated by SspA. Motility and chemotaxis genes are strongly down-regulated by AZT, possibly as a result of one of more of the small RNAs or other transcription factors such as AppY and GadE, whose expression is elevated by AZT. Genes controlling the iron siderophore, enterobactin, and iron homeostasis are also strongly induced, independent of LexA. We confirm that IraD antiadaptor protein is induced independent of LexA and that a second antiadaptor, IraM is likewise strongly AZT-inducible, independent of LexA, suggesting that RpoS stabilization via these antiadaptor proteins is an integral part of replication stress tolerance.
Collapse
Affiliation(s)
- Thalia H Sass
- Department of Biology, Brandeis University, Waltham, MA 02454-9110
- Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, MA 02454-9110
| | - Susan T Lovett
- Department of Biology, Brandeis University, Waltham, MA 02454-9110
- Rosenstiel Basic Medical Sciences Research Center MS029, Brandeis University, Waltham, MA 02454-9110
| |
Collapse
|
2
|
Wei N, Zha F, Zhou L, Xu H, Liu Z, Meng Q, Zhu T, Yin J, Yu Z. ppGpp is a dual-role regulator involved in balancing iron absorption and prodiginine biosynthesis in Pseudoalteromonas. Mol Microbiol 2024; 122:68-80. [PMID: 38845079 DOI: 10.1111/mmi.15285] [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: 12/21/2023] [Revised: 04/26/2024] [Accepted: 05/29/2024] [Indexed: 07/21/2024]
Abstract
Iron is an essential element for microbial survival and secondary metabolism. However, excess iron availability and overloaded secondary metabolites can hinder microbial growth and survival. Microorganisms must tightly control iron homeostasis and secondary metabolism. Our previous studies have found that the stringent starvation protein A (SspA) positively regulates prodiginine biosynthesis by activating iron uptake in Pseudoalteromonas sp. strain R3. It is believed that the interaction between SspA and the small nucleotide ppGpp is important for iron to exert regulation functions. However, the roles of ppGpp in iron absorption and prodiginine biosynthesis, and the underlying relationship between ppGpp and SspA in strain R3 remain unclear. In this study, we found that ppGpp accumulation in strain R3 could be induced by limiting iron. In addition, ppGpp not only positively regulated iron uptake and prodiginine biosynthesis via increasing the SspA level but also directly repressed iron uptake and prodiginine biosynthesis independent of SspA, highlighting the finding that ppGpp can stabilize both iron levels and prodiginine production. Notably, the abolishment of ppGpp significantly increased prodiginine production, thus providing a theoretical basis for manipulating prodiginine production in the future. This dynamic ppGpp-mediated interaction between iron uptake and prodiginine biosynthesis has significant implications for understanding the roles of nutrient uptake and secondary metabolism for the survival of bacteria in unfavorable environments.
Collapse
Affiliation(s)
- Ning Wei
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Fanglan Zha
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Luosai Zhou
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Hongyang Xu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Zhuangzhuang Liu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Qiu Meng
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Tingheng Zhu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Jianhua Yin
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| | - Zhiliang Yu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou, Zhejiang Province, China
| |
Collapse
|
3
|
Joron K, Zamel J, Kalisman N, Lerner E. Evidence for a compact σ 70 conformation in vitro and in vivo. iScience 2024; 27:110140. [PMID: 38957792 PMCID: PMC11217687 DOI: 10.1016/j.isci.2024.110140] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 03/28/2024] [Accepted: 05/27/2024] [Indexed: 07/04/2024] Open
Abstract
The initiation of transcription in Escherichia coli (E. coli) is facilitated by promoter specificity factors, also known as σ factors, which may bind a promoter only as part of a complex with RNA polymerase (RNAP). By performing in vitro cross-linking mass spectrometry (CL-MS) of apo-σ70, we reveal structural features suggesting a compact conformation compared to the known RNAP-bound extended conformation. Then, we validate the existence of the compact conformation using in vivo CL-MS by identifying cross-links similar to those found in vitro, which deviate from the extended conformation only during the stationary phase of bacterial growth. Conclusively, we provide information in support of a compact conformation of apo-σ70 that exists in live cells, which might represent a transcriptionally inactive form that can be activated upon binding to RNAP.
Collapse
Affiliation(s)
- Khalil Joron
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, Edmond J. Safra Campus, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Joanna Zamel
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, Edmond J. Safra Campus, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Nir Kalisman
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, Edmond J. Safra Campus, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| | - Eitan Lerner
- Department of Biological Chemistry, Alexander Silberman Institute of Life Sciences, Faculty of Mathematics & Science, Edmond J. Safra Campus, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
- Center for Nanoscience and Nanotechnology, Hebrew University of Jerusalem, Jerusalem 9190401, Israel
| |
Collapse
|
4
|
Kompaniiets D, Wang D, Yang Y, Hu Y, Liu B. Structure and molecular mechanism of bacterial transcription activation. Trends Microbiol 2024; 32:379-397. [PMID: 37903670 DOI: 10.1016/j.tim.2023.10.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 09/27/2023] [Accepted: 10/03/2023] [Indexed: 11/01/2023]
Abstract
Transcription activation is an important checkpoint of regulation of gene expression which occurs in response to different intracellular and extracellular signals. The key elements in this signal transduction process are transcription activators, which determine when and how gene expression is activated. Recent structural studies on a considerable number of new transcription activation complexes (TACs) revealed the remarkable mechanistic diversity of transcription activation mediated by different factors, necessitating a review and re-evaluation of the transcription activation mechanisms. In this review, we present a comprehensive summary of transcription activation mechanisms and propose a new, elaborate, and systematic classification of transcription activation mechanisms, primarily based on the structural features of diverse TAC components.
Collapse
Affiliation(s)
- Dmytro Kompaniiets
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Dong Wang
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA
| | - Yang Yang
- Roy J. Carver Department of Biochemistry, Biophysics and Molecular Biology, Iowa State University, Ames, IA, USA
| | - Yangbo Hu
- State Key Laboratory of Virology, Wuhan Institute of Virology, Center for Biosafety Mega-Science, Chinese Academy of Sciences, Wuhan 430071, China.
| | - Bin Liu
- Section of Transcription and Gene Regulation, The Hormel Institute, University of Minnesota, Austin, MN 55912, USA.
| |
Collapse
|
5
|
Degabriel M, Valeva S, Boisset S, Henry T. Pathogenicity and virulence of Francisella tularensis. Virulence 2023; 14:2274638. [PMID: 37941380 PMCID: PMC10653695 DOI: 10.1080/21505594.2023.2274638] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2023] [Accepted: 10/18/2023] [Indexed: 11/10/2023] Open
Abstract
Tularaemia is a zoonotic disease caused by the Gram-negative bacterium, Francisella tularensis. Depending on its entry route into the organism, F. tularensis causes different diseases, ranging from life-threatening pneumonia to less severe ulceroglandular tularaemia. Various strains with different geographical distributions exhibit different levels of virulence. F. tularensis is an intracellular bacterium that replicates primarily in the cytosol of the phagocytes. The main virulence attribute of F. tularensis is the type 6 secretion system (T6SS) and its effectors that promote escape from the phagosome. In addition, F. tularensis has evolved a peculiar envelope that allows it to escape detection by the immune system. In this review, we cover tularaemia, different Francisella strains, and their pathogenicity. We particularly emphasize the intracellular life cycle, associated virulence factors, and metabolic adaptations. Finally, we present how F. tularensis largely escapes immune detection to be one of the most infectious and lethal bacterial pathogens.
Collapse
Affiliation(s)
- Manon Degabriel
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
| | - Stanimira Valeva
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
| | - Sandrine Boisset
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
- Univ. Grenoble Alpes, CHU Grenoble Alpes, CNRS, CEA, UMR5075, Institut de Biologie Structurale, Grenoble, France
| | - Thomas Henry
- CIRI, Centre International de Recherche en Infectiologie, Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, ENS de Lyon, Univ Lyon, LYON, France
| |
Collapse
|
6
|
Holmes CL, Wilcox AE, Forsyth V, Smith SN, Moricz BS, Unverdorben LV, Mason S, Wu W, Zhao L, Mobley HLT, Bachman MA. Klebsiella pneumoniae causes bacteremia using factors that mediate tissue-specific fitness and resistance to oxidative stress. PLoS Pathog 2023; 19:e1011233. [PMID: 37463183 PMCID: PMC10381055 DOI: 10.1371/journal.ppat.1011233] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/28/2023] [Indexed: 07/20/2023] Open
Abstract
Gram-negative bacteremia is a major cause of global morbidity involving three phases of pathogenesis: initial site infection, dissemination, and survival in the blood and filtering organs. Klebsiella pneumoniae is a leading cause of bacteremia and pneumonia is often the initial infection. In the lung, K. pneumoniae relies on many factors like capsular polysaccharide and branched chain amino acid biosynthesis for virulence and fitness. However, mechanisms directly enabling bloodstream fitness are unclear. Here, we performed transposon insertion sequencing (TnSeq) in a tail-vein injection model of bacteremia and identified 58 K. pneumoniae bloodstream fitness genes. These factors are diverse and represent a variety of cellular processes. In vivo validation revealed tissue-specific mechanisms by which distinct factors support bacteremia. ArnD, involved in Lipid A modification, was required across blood filtering organs and supported resistance to soluble splenic factors. The purine biosynthesis enzyme PurD supported liver fitness in vivo and was required for replication in serum. PdxA, a member of the endogenous vitamin B6 biosynthesis pathway, optimized replication in serum and lung fitness. The stringent response regulator SspA was required for splenic fitness yet was dispensable in the liver. In a bacteremic pneumonia model that incorporates initial site infection and dissemination, splenic fitness defects were enhanced. ArnD, PurD, DsbA, SspA, and PdxA increased fitness across bacteremia phases and each demonstrated unique fitness dynamics within compartments in this model. SspA and PdxA enhanced K. pnuemoniae resistance to oxidative stress. SspA, but not PdxA, specifically resists oxidative stress produced by NADPH oxidase Nox2 in the lung, spleen, and liver, as it was a fitness factor in wild-type but not Nox2-deficient (Cybb-/-) mice. These results identify site-specific fitness factors that act during the progression of Gram-negative bacteremia. Defining K. pneumoniae fitness strategies across bacteremia phases could illuminate therapeutic targets that prevent infection and sepsis.
Collapse
Affiliation(s)
- Caitlyn L Holmes
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Alexis E Wilcox
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Valerie Forsyth
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Sara N Smith
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Bridget S Moricz
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Lavinia V Unverdorben
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Sophia Mason
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Weisheng Wu
- Bioinformatics Core Facility, School of Medicine, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Lili Zhao
- Research Institute, Beaumont Hospital, Royal Oak, Michigan, United States of America
| | - Harry L T Mobley
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| | - Michael A Bachman
- Department of Pathology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
- Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor, Michigan, United States of America
| |
Collapse
|
7
|
Lilic M, Holmes NA, Bush MJ, Marti AK, Widdick DA, Findlay KC, Choi YJ, Froom R, Koh S, Buttner MJ, Campbell EA. Structural basis of dual activation of cell division by the actinobacterial transcription factors WhiA and WhiB. Proc Natl Acad Sci U S A 2023; 120:e2220785120. [PMID: 36888660 PMCID: PMC10243135 DOI: 10.1073/pnas.2220785120] [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: 12/06/2022] [Accepted: 01/26/2023] [Indexed: 03/09/2023] Open
Abstract
Studies of transcriptional initiation in different bacterial clades reveal diverse molecular mechanisms regulating this first step in gene expression. The WhiA and WhiB factors are both required to express cell division genes in Actinobacteria and are essential in notable pathogens such as Mycobacterium tuberculosis. The WhiA/B regulons and binding sites have been elucidated in Streptomyces venezuelae (Sven), where they coordinate to activate sporulation septation. However, how these factors cooperate at the molecular level is not understood. Here we present cryoelectron microscopy structures of Sven transcriptional regulatory complexes comprising RNA polymerase (RNAP) σA-holoenzyme and WhiA and WhiB, in complex with the WhiA/B target promoter sepX. These structures reveal that WhiB binds to domain 4 of σA (σA4) of the σA-holoenzyme, bridging an interaction with WhiA while making non-specific contacts with the DNA upstream of the -35 core promoter element. The N-terminal homing endonuclease-like domain of WhiA interacts with WhiB, while the WhiA C-terminal domain (WhiA-CTD) makes base-specific contacts with the conserved WhiA GACAC motif. Notably, the structure of the WhiA-CTD and its interactions with the WhiA motif are strikingly similar to those observed between σA4 housekeeping σ-factors and the -35 promoter element, suggesting an evolutionary relationship. Structure-guided mutagenesis designed to disrupt these protein-DNA interactions reduces or abolishes developmental cell division in Sven, confirming their significance. Finally, we compare the architecture of the WhiA/B σA-holoenzyme promoter complex with the unrelated but model CAP Class I and Class II complexes, showing that WhiA/WhiB represent a new mechanism in bacterial transcriptional activation.
Collapse
Affiliation(s)
- Mirjana Lilic
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY10065
| | - Neil A. Holmes
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, UK
| | - Matthew J. Bush
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, UK
| | - Alexandra K. Marti
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, UK
| | - David A. Widdick
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, UK
| | - Kim C. Findlay
- Department of Cell and Developmental Biology, John Innes Centre, NorwichNR4 7UH, UK
| | - Young Joo Choi
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY10065
| | - Ruby Froom
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY10065
| | - Steven Koh
- Laboratory of Molecular Biophysics, The Rockefeller University, New York, NY10065
| | - Mark J. Buttner
- Department of Molecular Microbiology, John Innes Centre, NorwichNR4 7UH, UK
| | | |
Collapse
|
8
|
Wu X, Yu C, Mu W, Gu Z, Feng Y, Zhang Y. The structural mechanism for transcription activation by Caulobacter crescentus GcrA. Nucleic Acids Res 2023; 51:1960-1970. [PMID: 36715319 PMCID: PMC9976885 DOI: 10.1093/nar/gkad016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2022] [Revised: 12/28/2022] [Accepted: 01/05/2023] [Indexed: 01/31/2023] Open
Abstract
Canonical bacterial transcription activators bind to their cognate cis elements at the upstream of transcription start site (TSS) in a form of dimer. Caulobacter crescentus GcrA, a non-canonical transcription activator, can activate transcription from promoters harboring its cis element at the upstream or downstream of TSS in a form of monomer. We determined two cryo-EM structures of C. crescentus GcrA-bound transcription activation complexes, GcrA TACU and GcrA TACD, which comprise GcrA, RNAP, σ70 and promoter DNA with GcrA cis elements at either the upstream or downstream of TSS at 3.6 and 3.8 Å, respectively. In the GcrA-TACU structure, GcrA makes bipartite interactions with both σ70 domain 2 (σ702) and its cis element, while in the GcrA-TACD structure, GcrA retains interaction with σ702 but loses the interaction with its cis element. Our results suggest that GcrA likely forms a functionally specialized GcrA-RNAP-σA holoenzyme, in which GcrA first locates its cis element and then facilitates RNAP to load on core promoter at its proximal region. The sequence-specific interaction of GcrA and DNA is disrupted either at the stage of RPo formation or promoter escape depending on the location of GcrA cis elements relative to TSS.
Collapse
Affiliation(s)
- Xiaoxian Wu
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| | - Chengzhi Yu
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wenhui Mu
- Key Laboratory of Plant Stress Biology, State Key Laboratory of Cotton Biology, School of Life Sciences, Henan University, Kaifeng 475004, China
| | - Zhanxi Gu
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China.,University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yu Feng
- Department of Biophysics, and Department of Infectious Disease of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Yu Zhang
- Key Laboratory of Synthetic Biology, Center for Excellence in Molecular Plant Sciences, Shanghai Institute of Plant Physiology and Ecology, Chinese Academy of Sciences, Shanghai 200032, China
| |
Collapse
|
9
|
Cheng A, Wan D, Ghatak A, Wang C, Feng D, Fondell JD, Ebright RH, Fan H. Identification and Structural Modeling of the RNA Polymerase Omega Subunits in Chlamydiae and Other Obligate Intracellular Bacteria. mBio 2023; 14:e0349922. [PMID: 36719197 PMCID: PMC9973325 DOI: 10.1128/mbio.03499-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2022] [Accepted: 01/04/2023] [Indexed: 02/01/2023] Open
Abstract
Gene transcription in bacteria is carried out by the multisubunit RNA polymerase (RNAP), which is composed of a catalytic core enzyme and a promoter-recognizing σ factor. The core enzyme comprises two α subunits, one β subunit, one β' subunit, and one ω subunit. The ω subunit plays critical roles in the assembly of the core enzyme and other cellular functions, including the regulation of bacterial growth, the stress response, and biofilm formation. However, the identity of an ω subunit for the obligate intracellular bacterium Chlamydia has not previously been determined. Here, we report the identification of the hypothetical protein CTL0286 as the probable chlamydial ω subunit based on sequence, synteny, and AlphaFold and AlphaFold-Multimer three-dimensional-structure predictions. Our findings indicate that CTL0286 functions as the missing ω subunit of chlamydial RNAP. Our extended analysis also indicates that all obligate intracellular bacteria have ω orthologs. IMPORTANCE Chlamydiae are obligate intracellular bacteria that replicate only inside eukaryotic cells. Previously, it has not been possible to identify a candidate gene encoding the chlamydial RNA polymerase ω subunit, and it has been hypothesized that the chlamydial RNA polymerase ω subunit was lost in the evolutionary process through which Chlamydiae reduced their genome size and proteome sizes to adapt to an obligate intracellular lifestyle. Here, we report the identification of the chlamydial RNA polymerase ω subunit, based on conserved sequence, conserved synteny, AlphaFold-predicted conserved three-dimensional structure, and AlfaFold-Multimer-predicted conserved interactions. Our identification of the previously elusive chlamydial RNA polymerase ω subunit sets the stage for investigation of its roles in regulation of gene expression during chlamydial growth, development, and stress responses, and sets the stage for preparation and study of the intact chlamydial RNA polymerase and its interactions with inhibitors.
Collapse
Affiliation(s)
- Andrew Cheng
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Danny Wan
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
- Graduate Program in Physiology and Integrative Biology, Rutgers School of Graduate Studies, Piscataway, New Jersey, USA
| | - Arkaprabha Ghatak
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Chengyuan Wang
- Center for Microbes, Development and Health, CAS Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Deyu Feng
- Center for Microbes, Development and Health, CAS Key Laboratory of Molecular Virology and Immunology, Institute Pasteur of Shanghai, Chinese Academy of Sciences, Shanghai, China
| | - Joseph D. Fondell
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| | - Richard H. Ebright
- Waksman Institute, Rutgers University, Piscataway, New Jersey, USA
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey, USA
| | - Huizhou Fan
- Department of Pharmacology, Rutgers-Robert Wood Johnson Medical School, Piscataway, New Jersey, USA
| |
Collapse
|
10
|
Trautmann HS, Ramsey KM. A Ribosomal Protein Homolog Governs Gene Expression and Virulence in a Bacterial Pathogen. J Bacteriol 2022; 204:e0026822. [PMID: 36121290 PMCID: PMC9578407 DOI: 10.1128/jb.00268-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2022] [Accepted: 08/24/2022] [Indexed: 11/20/2022] Open
Abstract
The molecular machine necessary for protein synthesis, the ribosome, is generally considered constitutively functioning and lacking any inherent regulatory capacity. Yet ribosomes are commonly heterogeneous in composition and the impact of ribosome heterogeneity on translation is not well understood. Here, we determined that changes in ribosome protein composition govern gene expression in the intracellular bacterial pathogen Francisella tularensis. F. tularensis encodes three distinct homologs for bS21, a ribosomal protein involved in translation initiation, and analysis of purified F. tularensis ribosomes revealed they are heterogeneous with respect to bS21. The loss of one homolog, bS21-2, resulted in significant changes to the cellular proteome unlinked to changes in the transcriptome. Among the reduced proteins were components of the type VI secretion system (T6SS), an essential virulence factor encoded by the Francisella Pathogenicity Island. Furthermore, loss of bS21-2 led to an intramacrophage growth defect. Although multiple bS21 homologs complemented the loss of bS21-2 with respect to T6SS protein abundance, bS21-2 was uniquely necessary for robust intramacrophage growth, suggesting bS21-2 modulates additional virulence gene(s) distinct from the T6SS. Our results indicate that ribosome composition in F. tularensis, either directly or indirectly, posttranscriptionally modulates gene expression and virulence. Our findings are consistent with a model in which bS21 homologs function as posttranscriptional regulators, allowing preferential translation of specific subsets of mRNAs, likely at the stage of translation initiation. This work also raises the possibility that bS21 in other organisms may function similarly and that ribosome heterogeneity may permit many bacteria to posttranscriptionally regulate gene expression. IMPORTANCE While bacterial ribosomes are commonly heterogeneous in composition (e.g., incorporating different homologs for a ribosomal protein), how heterogeneity impacts translation is unclear. We found that the intracellular human pathogen Francisella tularensis has heterogeneous ribosomes, incorporating one of three homologs for ribosomal protein bS21. Furthermore, one bS21 homolog posttranscriptionally governs the expression of the F. tularensis type VI secretion system, an essential virulence factor. This bS21 homolog is also uniquely important for robust intracellular growth. Our data support a model in which bS21 heterogeneity leads to modulation of translation, providing another source of posttranscriptional gene regulation. Regulation of translation by bS21, or other sources of ribosomal heterogeneity, may be a conserved mechanism to control gene expression across the bacterial phylogeny.
Collapse
Affiliation(s)
- Hannah S. Trautmann
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island, USA
| | - Kathryn M. Ramsey
- Department of Cell and Molecular Biology, University of Rhode Island, Kingston, Rhode Island, USA
- Department of Biomedical and Pharmaceutical Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| |
Collapse
|
11
|
Cantlay S, Kaftanic C, Horzempa J. PdpC, a secreted effector protein of the type six secretion system, is required for erythrocyte invasion by Francisella tularensis LVS. Front Cell Infect Microbiol 2022; 12:979693. [PMID: 36237421 PMCID: PMC9552824 DOI: 10.3389/fcimb.2022.979693] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Accepted: 09/02/2022] [Indexed: 12/01/2022] Open
Abstract
Francisella tularensis is a gram negative, intracellular pathogen that is the causative agent of the potentially fatal disease, tularemia. During infection, F. tularensis is engulfed by and replicates within host macrophages. Additionally, this bacterium has also been shown to invade human erythrocytes and, in both cases, the Type Six Secretion System (T6SS) is required for these host-pathogen interaction. One T6SS effector protein, PdpC, is important for macrophage infection, playing a role in phagolysosomal escape and intracellular replication. To determine if PdpC also plays a role in erythrocyte invasion, we constructed a pdpC-null mutant in the live vaccine strain, F. tularensis LVS. We show that PdpC is required for invasion of human and sheep erythrocytes during in vitro assays and that reintroduction of a copy of pdpC, in trans, rescues this phenotype. The interaction with human erythrocytes was further characterized using double-immunofluorescence microscopy to show that PdpC is required for attachment of F. tularensis LVS to erythrocytes as well as invasion. To learn more about the role of PdpC in erythrocyte invasion we generated a strain of F. tularensis LVS expressing pdpC-emgfp. PdpC-EmGFP localizes as discrete foci in a subset of F. tularensis LVS cells grown in broth culture and accumulates in erythrocytes during invasion assays. Our results are the first example of a secreted effector protein of the T6SS shown to be involved in erythrocyte invasion and indicate that PdpC is secreted into erythrocytes during invasion.
Collapse
Affiliation(s)
| | | | - Joseph Horzempa
- Department of Biological Sciences, West Liberty University, West Liberty, WV, United States
| |
Collapse
|
12
|
Structural and Functional Analysis of Toxin and Small RNA Gene Promoter Regions in Bacillus anthracis. J Bacteriol 2022; 204:e0020022. [PMID: 36043862 PMCID: PMC9487513 DOI: 10.1128/jb.00200-22] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It was previously demonstrated that anthrax toxin activator (AtxA) binds directly to the σA-like promoter region of pagA (encoding protective antigen, PA) immediately upstream of the RNA polymerase binding site. In this study, using electrophoretic mobility shift assays and in vivo analyses, we identified AtxA-binding sites in the promoter regions of the lef and cya genes (encoding lethal and edema factors, respectively) and of two Bacillus anthracis small RNAs (XrrA and XrrB). Activities of all four newly studied promoters were enhanced in the presence of CO2/bicarbonate and AtxA, as previously seen for the pagA promoter. Notably, the cya promoter was less activated by AtxA and CO2/bicarbonate conditions. The putative promoter of a recently described third small RNA, XrrC, showed a negligible response to AtxA and CO2/bicarbonate. RNA polymerase binding sites of the newly studied promoters show no consensus and differ from the σA-like promoter region of pagA. In silico analysis of the probable AtxA binding sites in the studied promoters revealed several palindromes. All the analyzed palindromes showed very little overlap with the σA-like pagA promoter. It remains unclear as to how AtxA and DNA-dependent RNA-polymerase identify such diverse DNA-sequences and differentially regulate promoter activation of the studied genes. IMPORTANCE Anthrax toxin activator (AtxA) is the major virulence regulator of Bacillus anthracis, the causative agent of anthrax. Understanding AtxA's mechanism of regulation could facilitate the development of therapeutics for B. anthracis infection. We provide evidence that AtxA binds to the promoters of the cya, lef, xrrA, and xrrB genes. In vivo assays confirmed the activities of all four promoters were enhanced in the presence of AtxA and CO2/bicarbonate, as previously seen for the pagA promoter. The cya and lef genes encode important toxin components. The xrrA and xrrB genes encode sRNAs with a suggested function as cell physiology regulators. Our data provides further evidence for the direct regulatory role of AtxA that was previously shown with the pagA promoter.
Collapse
|
13
|
Yue Y, Puniya BL, Helikar T, Girardo B, Hinrichs SH, Larson MA. Arginine Catabolism and Polyamine Biosynthesis Pathway Disparities Within Francisella tularensis Subpopulations. Front Microbiol 2022; 13:890856. [PMID: 35794913 PMCID: PMC9251427 DOI: 10.3389/fmicb.2022.890856] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Accepted: 05/27/2022] [Indexed: 11/13/2022] Open
Abstract
Francisella tularensis is a highly infectious zoonotic pathogen with as few as 10 organisms causing tularemia, a disease that is fatal if untreated. Although F. tularensis subspecies tularensis (type A) and subspecies holarctica (type B) share over 99.5% average nucleotide identity, notable differences exist in genomic organization and pathogenicity. The type A clade has been further divided into subtypes A.I and A.II, with A.I strains being recognized as some of the most virulent bacterial pathogens known. In this study, we report on major disparities that exist between the F. tularensis subpopulations in arginine catabolism and subsequent polyamine biosynthesis. The genes involved in these pathways include the speHEA and aguAB operons, along with metK. In the hypervirulent F. tularensis A.I clade, such as the A.I prototype strain SCHU S4, these genes were found to be intact and highly transcribed. In contrast, both subtype A.II and type B strains have a truncated speA gene, while the type B clade also has a disrupted aguA and truncated aguB. Ablation of the chromosomal speE gene that encodes a spermidine synthase reduced subtype A.I SCHU S4 growth rate, whereas the growth rate of type B LVS was enhanced. These results demonstrate that spermine synthase SpeE promotes faster replication in the F. tularensis A.I clade, whereas type B strains do not rely on this enzyme for in vitro fitness. Our ongoing studies on amino acid and polyamine flux within hypervirulent A.I strains should provide a better understanding of the factors that contribute to F. tularensis pathogenicity.
Collapse
Affiliation(s)
- Yinshi Yue
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Bhanwar Lal Puniya
- Department of Biochemistry, University of Nebraska–Lincoln, Lincoln, NE, United States
| | - Tomáš Helikar
- Department of Biochemistry, University of Nebraska–Lincoln, Lincoln, NE, United States
| | - Benjamin Girardo
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Steven H. Hinrichs
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
| | - Marilynn A. Larson
- Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE, United States
- *Correspondence: Marilynn A. Larson,
| |
Collapse
|
14
|
Sass TH, Ferrazzoli AE, Lovett ST. DnaA and SspA regulation of the iraD gene of Escherichia coli: an alternative DNA damage response independent of LexA/RecA. Genetics 2022; 221:6571813. [PMID: 35445706 PMCID: PMC9157160 DOI: 10.1093/genetics/iyac062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Accepted: 10/05/2021] [Indexed: 11/13/2022] Open
Abstract
The transcription factor RpoS of Escherichia coli controls many genes important for tolerance of a variety of stress conditions. IraD promotes the post-translation stability of RpoS by inhibition of RssB, an adaptor protein for ClpXP degradation. We have previously documented DNA damage induction of iraD expression, independent of the SOS response. Both iraD and rpoS are required for tolerance to DNA damaging treatments such as H2O2 and the replication inhibitor azidothymidine in the log phase of growth. Using luciferase gene fusions to the 672 bp iraD upstream region, we show here that both promoters of iraD are induced by azidothymidine. Genetic analysis suggests that both promoters are repressed by DnaA-ATP, partially dependent on a putative DnaA box at -81 bp and are regulated by regulatory inactivation of DnaA, dependent on the DnaN processivity clamp. By electrophoretic mobility shift assays, we show that purified DnaA protein binds to the iraD upstream region, so DnaA regulation of IraD is likely to be direct. DNA damage induction of iraD during log phase growth is abolished in the dnaA-T174P mutant, suggesting that DNA damage, in some way, relieves DnaA repression, possibly through the accumulation of replication clamps and enhanced regulatory inactivation of DnaA. We also demonstrate that the RNA-polymerase associated factor, stringent starvation protein A, induced by the accumulation of ppGpp, also affects iraD expression, with a positive effect on constitutive expression and a negative effect on azidothymidine-induced expression.
Collapse
Affiliation(s)
- Thalia H Sass
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, USA
| | - Alexander E Ferrazzoli
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, USA
| | - Susan T Lovett
- Department of Biology, Rosenstiel Basic Medical Sciences Research Center, Brandeis University, Waltham, MA 02454-9110, USA
| |
Collapse
|
15
|
Sohrabi H, Majidi MR, Fakhraei M, Jahanban-Esfahlan A, Hejazi M, Oroojalian F, Baradaran B, Tohidast M, Guardia MDL, Mokhtarzadeh A. Lateral flow assays (LFA) for detection of pathogenic bacteria: A small point-of-care platform for diagnosis of human infectious diseases. Talanta 2022; 243:123330. [DOI: 10.1016/j.talanta.2022.123330] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 02/17/2022] [Accepted: 02/19/2022] [Indexed: 12/31/2022]
|
16
|
Travis BA, Schumacher MA. Diverse molecular mechanisms of transcription regulation by the bacterial alarmone ppGpp. Mol Microbiol 2021; 117:252-260. [PMID: 34894005 PMCID: PMC9304144 DOI: 10.1111/mmi.14860] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Revised: 12/07/2021] [Accepted: 12/07/2021] [Indexed: 12/30/2022]
Abstract
Bacteria must rapidly detect and respond to stressful environmental conditions. Guanosine tetraphosphate (ppGpp) is a universal stress signal that, in most bacteria, drives the reprograming of transcription at a global level. However, recent studies have revealed that the molecular mechanisms utilized by ppGpp to rewire bacterial transcriptomes are unexpectedly diverse. In Proteobacteria, ppGpp regulates the expression of hundreds of genes by directly binding to two sites on RNA polymerase (RNAP), one in combination with the transcription factor, DksA. Conversely, ppGpp indirectly regulates transcription in Firmicutes by controlling GTP levels. In this case, ppGpp inhibits enzymes that salvage and synthesize GTP, which indirectly represses transcription from rRNA and other promoters that use GTP for initiation. More recently, two different mechanisms of transcription regulation involving the direct binding of transcription factors by ppGpp have been described. First, in Francisella tularensis, ppGpp was shown to modulate the formation of a tripartite transcription factor complex that binds RNAP and activates virulence genes. Second, in Firmicutes, ppGpp allosterically regulates the transcription repressor, PurR, which controls purine biosynthesis genes. The diversity in bacterial ppGpp signaling revealed in these studies suggests the likelihood that additional paradigms in ppGpp-mediated transcription regulation await discovery.
Collapse
Affiliation(s)
- Brady A Travis
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| | - Maria A Schumacher
- Department of Biochemistry, Duke University Medical Center, Durham, North Carolina, USA
| |
Collapse
|
17
|
Wang F, Feng Y, Shang Z, Lin W. A unique binding between SspA and RNAP β 'NTH across low-GC Gram-negative bacteria facilitates SspA-mediated transcription regulation. Biochem Biophys Res Commun 2021; 583:86-92. [PMID: 34735884 DOI: 10.1016/j.bbrc.2021.10.048] [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: 10/15/2021] [Revised: 10/18/2021] [Accepted: 10/18/2021] [Indexed: 11/19/2022]
Abstract
Stringent starvation protein A (SspA) involved in nucleotide metabolism, acid tolerance and virulence of bacteria has been demonstrated to function as a transcription factor to regulate σ70-dependent gene transcription through interacting with σ70 region 4 and the zinc binding domain (ZBD) of E. coli RNA polymerase (EcoRNAP) β' subunit simultaneously. Despite extensive biochemical and structural analyses were reported recently, the interactions of SspA with RNAP are not comprehensively understood. Here, we reprocessed our previous cryo-EM dataset of EcoRNAP-promoter open complex with SspA (SspA-RPo) and obtained a significantly improved density map. Unexpectedly, the new map showed that SspA interacts with both N-terminal helix of β' subunit (β'ΝΤΗ) and ω subunit, which contributes to stabilize the SspA-EcoRNAP σ70 holoenzyme complex. Sequence alignments and phylogenetic tree analyses of N-terminal sequences of β' subunit from different classes of bacteria revealed that β'ΝΤΗ is highly conserved and exclusively found in low-GC-content Gram-negative bacteria that harbor SspA, implying a co-evolution of β'ΝΤΗ and SspA. The transcription assays of wild-type SspA and its mutants demonstrated the interaction between SspA and β'ΝΤΗ facilitates the transcription regulation of SspA. Together, our results provide a more comprehensive insight into the interactions between SspA and RNAP and their roles in bacterial transcription regulation.
Collapse
Affiliation(s)
- Fulin Wang
- Department of Pathogen Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China; State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China; Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing, 210023, China
| | - Yu Feng
- Department of Biophysics, And Department of Pathology of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, China; Zhejiang Provincial Key Laboratory of Immunity and Inflammatory Diseases, Hangzhou, China.
| | - Zhuo Shang
- Department of Pathogen Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China.
| | - Wei Lin
- Department of Pathogen Biology, School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China; State Key Laboratory of Natural Medicines, China Pharmaceutical University, Nanjing, China; Jiangsu Collaborative Innovation Center of Chinese Medicinal Resources Industrialization, Nanjing, 210023, China.
| |
Collapse
|
18
|
Chau NYE, Ahmad S, Whitney JC, Coombes BK. Emerging and divergent roles of pyrophosphorylated nucleotides in bacterial physiology and pathogenesis. PLoS Pathog 2021; 17:e1009532. [PMID: 33984072 PMCID: PMC8118318 DOI: 10.1371/journal.ppat.1009532] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
Bacteria inhabit diverse environmental niches and consequently must modulate their metabolism to adapt to stress. The nucleotide second messengers guanosine tetraphosphate (ppGpp) and guanosine pentaphosphate (pppGpp) (collectively referred to as (p)ppGpp) are essential for survival during nutrient starvation. (p)ppGpp is synthesized by the RelA-SpoT homologue (RSH) protein family and coordinates the control of cellular metabolism through its combined effect on over 50 proteins. While the role of (p)ppGpp has largely been associated with nutrient limitation, recent studies have shown that (p)ppGpp and related nucleotides have a previously underappreciated effect on different aspects of bacterial physiology, such as maintaining cellular homeostasis and regulating bacterial interactions with a host, other bacteria, or phages. (p)ppGpp produced by pathogenic bacteria facilitates the evasion of host defenses such as reactive nitrogen intermediates, acidic pH, and the complement system. Additionally, (p)ppGpp and pyrophosphorylated derivatives of canonical adenosine nucleotides called (p)ppApp are emerging as effectors of bacterial toxin proteins. Here, we review the RSH protein family with a focus on its unconventional roles during host infection and bacterial competition.
Collapse
Affiliation(s)
- N. Y Elizabeth Chau
- Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - Shehryar Ahmad
- Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
| | - John C. Whitney
- Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
| | - Brian K. Coombes
- Department of Biochemistry & Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
- Michael G. DeGroote Institute for Infectious Disease Research, McMaster University, Hamilton, Ontario, Canada
- David Braley Centre for Antibiotic Discovery, McMaster University, Hamilton, Ontario, Canada
- * E-mail:
| |
Collapse
|
19
|
Saba J, Cao X, Landick R. Bacterial Transcription Continues to Surprise: Activation by Alarmone-Mediated σ-Factor Tethering. Mol Cell 2021; 81:8-9. [PMID: 33417856 DOI: 10.1016/j.molcel.2020.12.031] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Travis et al. (2020) reveal how Francisella tularensis uses stress-induced ppGpp to activate its virulent pathogenesis program by tethering an αCTD-DNA organizer (PigR) to a σ-organizing heterodimer (MglA-SspA), highlighting the remarkable diversity of transcriptional mechanisms in under-studied bacteria.
Collapse
Affiliation(s)
- Jason Saba
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Xinyun Cao
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA
| | - Robert Landick
- Department of Biochemistry, University of Wisconsin-Madison, Madison, WI 53706, USA; Department of Bacteriology, University of Wisconsin-Madison, Madison, WI 53706, USA.
| |
Collapse
|