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Hakiem OR, Batra JK. Role of HrcA in stress management in Mycobacterium tuberculosis. J Appl Microbiol 2021; 132:3315-3326. [PMID: 34953162 DOI: 10.1111/jam.15428] [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: 08/02/2021] [Revised: 12/20/2021] [Accepted: 12/21/2021] [Indexed: 11/26/2022]
Abstract
AIM The current study aims to understand the role of HrcA in stress response of M. tuberculosis. METHODS AND RESULTS In this study, using an hrcA knock out mutant of M. tuberculosis it is demonstrated that the heat shock repressor, HrcA is important for countering environmental stresses pathogen faces within the host during the infection process. Also, with scanning electron microscopy it has been shown that HrcA plays a role in maintaining the morphology and cell size of the pathogen as disruption of the hrcA gene resulted in significantly elongated bacilli. Further, heat shock proteins like ClpC1, ClpB, DnaK, GroEL2, GroEL1, DnaJ2 and GroES were detected in the secretome of M. tuberculosis by mass spectrometric analysis. The study also demonstrates a strong humoral response against M. tuberculosis heat shock proteins in H37 Rv infected mice sera. CONCLUSION The study establishes that though hrcA is not an essential gene for M. tuberculosis, it regulates the expression of heat shock proteins during infection, and disruption of hrcA gives a survival advantage to the pathogen during stress conditions. SIGNIFICANCE and Impact of the Study: HrcA plays an important role in maintaining a fine balance of heat shock proteins during infection to give adequate survival advantage and also evade immune detection.
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Affiliation(s)
- Owais R Hakiem
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.,Current address: Microbiology and Molecular Genetics, University of California, Irvine, 92697, USA
| | - Janendra K Batra
- National Institute of Immunology, Aruna Asaf Ali Marg, New Delhi, 110067, India.,Department of Biochemistry, School of Chemical and Life Sciences, Jamia Hamdard, New, Delhi, 110062, India
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2
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Xu M, Dai Y, Huang Y, Yang J, Lai XH, Jin D, Lu S, Zhou J, Zhang S, Bai Y, Jiao Y, Qiao L, Jiang Y, Xu J. Identification of Haloactinobacterium kanbiaonis sp. nov. and Ruania zhangjianzhongii sp. nov., two novel species of the family Ruaniaceae isolated from faeces of bats ( Hipposideros spp.). Int J Syst Evol Microbiol 2021; 71. [PMID: 34388085 DOI: 10.1099/ijsem.0.004953] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Two pairs of aerobic, Gram-stain-positive, rod-shaped strains (HY164T/HY044, HY168T/HY211) were isolated from bat faecal samples. Strains HY164T and HY044 were motile with a polar flagellum, and had 16S rRNA gene similarity of 95.1-98.6 % to Haloactinobacterium album YIM 93306T and Haloactinobacterium glacieicola T3246-1T; strains HY168T and HY211 were most similar to Ruania albidiflava DSM 18029T (96.6 %). Phylogenetic trees based on 16S rRNA gene and whole genome sequences revealed affiliation of strains HY164T and HY168T to the family Ruaniaceae, representing novel lineages in the genera Haloactinobacterium and Ruania, respectively, which was also supported by the results for average nucleotide identity (ANI) and digital DNA-DNA hybridization (dDDH). For all isolates, the principal cellular fatty acids were anteiso-C15 : 0 and iso-C14 : 0. HY164T and HY168T had MK-8(H4) as the predominant isoprenoid quinone, diphosphatidylglycerol, phosphatidylglycerol, several unidentified phospholipids and glycolipids as common polar lipids while the latter strain additionally contained one unidentified aminophospholipid and one unidentified phosphoglycolipid. Besides sharing alanine, glutamic acid and lysine with HY164T, HY168T additionally contained 2,4-diaminobutyric acid in the cell-wall peptidoglycan. The whole-cell sugars of HY164T were ribose and rhamnose, while HY168T only included the latter. The DNA G+C contents of HY164T and HY168T were 71.0 and 69.1 mol%, respectively. Combining the polyphasic taxonomic data, HY164T (=CGMCC 4.7606T=JCM 33464T) is classified as representing a novel species of the genus Haloactinobacterium with the proposed name Haloactinobacterium kanbiaonis sp. nov., and HY168T (=CGMCC 1.16970T=JCM 33465T) is proposed to represent a novel species of the genus Ruania with the name Ruania zhangjianzhongii sp. nov.
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Affiliation(s)
- Mingchao Xu
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu Province, PR China.,State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China
| | - Yan Dai
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Collaborative Innovation Center for Biomedicine, School of Public Health, Guangxi Medical University, Nanning 530021, Guangxi Province, PR China
| | - Yuyuan Huang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China
| | - Jing Yang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Shanghai Institute for Emerging and Re-emerging Infectious Diseases, Shanghai Public Health Clinical Center, Shanghai 201508, PR China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing 100730, PR China
| | - Xin-He Lai
- Henan Key Laboratory of Biomolecular Recognition and Sensing, College of Chemistry and Chemical Engineering, Henan Joint International Research Laboratory of Chemo/Biosensing and Early Diagnosis of Major Diseases, Shangqiu Normal University, Shangqiu 476000, Henan Province, PR China
| | - Dong Jin
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Shanghai Institute for Emerging and Re-emerging Infectious Diseases, Shanghai Public Health Clinical Center, Shanghai 201508, PR China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing 100730, PR China
| | - Shan Lu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Shanghai Institute for Emerging and Re-emerging Infectious Diseases, Shanghai Public Health Clinical Center, Shanghai 201508, PR China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing 100730, PR China
| | - Juan Zhou
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China
| | - Sihui Zhang
- Department of Laboratorial Science and Technology & Vaccine Research Center, School of Public Health, Peking University, Beijing 100191, PR China
| | - Yibo Bai
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan 030001, Shanxi Province, PR China
| | - Yifan Jiao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan 030001, Shanxi Province, PR China
| | - Lei Qiao
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Department of Epidemiology, School of Public Health, Shanxi Medical University, Taiyuan 030001, Shanxi Province, PR China
| | - Yan Jiang
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu Province, PR China.,State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China
| | - Jianguo Xu
- Department of Epidemiology, Center for Global Health, School of Public Health, Nanjing Medical University, Nanjing 211166, Jiangsu Province, PR China.,State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing 102206, PR China.,Guangxi Key Laboratory of AIDS Prevention and Treatment & Guangxi Collaborative Innovation Center for Biomedicine, School of Public Health, Guangxi Medical University, Nanning 530021, Guangxi Province, PR China.,Shanghai Institute for Emerging and Re-emerging Infectious Diseases, Shanghai Public Health Clinical Center, Shanghai 201508, PR China.,Research Units of Discovery of Unknown Bacteria and Function, Chinese Academy of Medical Sciences, Beijing 100730, PR China
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3
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Schroeder K, Jonas K. The Protein Quality Control Network in Caulobacter crescentus. Front Mol Biosci 2021; 8:682967. [PMID: 33996917 PMCID: PMC8119881 DOI: 10.3389/fmolb.2021.682967] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 04/08/2021] [Indexed: 11/13/2022] Open
Abstract
The asymmetric life cycle of Caulobacter crescentus has provided a model in which to study how protein quality control (PQC) networks interface with cell cycle and developmental processes, and how the functions of these systems change during exposure to stress. As in most bacteria, the PQC network of Caulobacter contains highly conserved ATP-dependent chaperones and proteases as well as more specialized holdases. During growth in optimal conditions, these systems support a regulated circuit of protein synthesis and degradation that drives cell differentiation and cell cycle progression. When stress conditions threaten the proteome, most components of the Caulobacter proteostasis network are upregulated and switch to survival functions that prevent, revert, and remove protein damage, while simultaneously pausing the cell cycle in order to regain protein homeostasis. The specialized physiology of Caulobacter influences how it copes with proteotoxic stress, such as in the global management of damaged proteins during recovery as well as in cell type-specific stress responses. Our mini-review highlights the discoveries that have been made in how Caulobacter utilizes its PQC network for regulating its life cycle under optimal and proteotoxic stress conditions, and discusses open research questions in this model.
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Affiliation(s)
- Kristen Schroeder
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
| | - Kristina Jonas
- Science for Life Laboratory, Department of Molecular Biosciences, The Wenner-Gren Institute, Stockholm University, Stockholm, Sweden
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4
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Yus E, Lloréns-Rico V, Martínez S, Gallo C, Eilers H, Blötz C, Stülke J, Lluch-Senar M, Serrano L. Determination of the Gene Regulatory Network of a Genome-Reduced Bacterium Highlights Alternative Regulation Independent of Transcription Factors. Cell Syst 2019; 9:143-158.e13. [PMID: 31445891 PMCID: PMC6721554 DOI: 10.1016/j.cels.2019.07.001] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Revised: 04/14/2019] [Accepted: 06/27/2019] [Indexed: 11/30/2022]
Abstract
Here, we determined the relative importance of different transcriptional mechanisms in the genome-reduced bacterium Mycoplasma pneumoniae, by employing an array of experimental techniques under multiple genetic and environmental perturbations. Of the 143 genes tested (21% of the bacterium’s annotated proteins), only 55% showed an altered phenotype, highlighting the robustness of biological systems. We identified nine transcription factors (TFs) and their targets, representing 43% of the genome, and 16 regulators that indirectly affect transcription. Only 20% of transcriptional regulation is mediated by canonical TFs when responding to perturbations. Using a Random Forest, we quantified the non-redundant contribution of different mechanisms such as supercoiling, metabolic control, RNA degradation, and chromosome topology to transcriptional changes. Model-predicted gene changes correlate well with experimental data in 95% of the tested perturbations, explaining up to 70% of the total variance when also considering noise. This analysis highlights the importance of considering non-TF-mediated regulation when engineering bacteria. Full comprehensive reconstruction of a bacterial gene regulatory network achieved Genome-reduced bacterium Mycoplasma pneumoniae is robust to genetic perturbations Large part of transcription regulation in bacteria is transcription-factor independent Transcription-factor-independent regulation has a smaller dynamic range
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Affiliation(s)
- Eva Yus
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain.
| | - Verónica Lloréns-Rico
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain.
| | - Sira Martínez
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain
| | - Carolina Gallo
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain
| | - Hinnerk Eilers
- Department for General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Cedric Blötz
- Department for General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Jörg Stülke
- Department for General Microbiology, Georg-August-University Göttingen, 37077 Göttingen, Germany
| | - Maria Lluch-Senar
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain
| | - Luis Serrano
- Centre for Genomic Regulation (CRG), The Barcelona Institute for Science and Technology, Doctor Aiguader 88, Barcelona 08003, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluis Companys 23, Barcelona 08010, Spain.
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5
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Zhuo L, Zhang Z, Pan Z, Sheng DH, Hu W, Li YZ. CIRCE element evolved for the coordinated transcriptional regulation of bacterial duplicate groELs. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2018; 1861:928-937. [PMID: 30496038 DOI: 10.1016/j.bbagrm.2018.08.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2018] [Revised: 08/16/2018] [Accepted: 08/23/2018] [Indexed: 01/16/2023]
Abstract
Chaperonin groEL genes are duplicated in approximately 20% of bacteria, and the duplicates are differentially transcribed due to their divergent functions. The coordinated regulation of this differential transcription is as yet undetermined. In this study, we reported that the controlling inverted repeat of chaperone expression (CIRCE) element (the HrcA-binding site located upstream of the promoter) evolved for the transcriptional regulation of duplicate groELs. CIRCE composition and locations were found to be phylogenetically conserved in bacterial taxa. Myxococcus xanthus DK1622 has two CIRCE elements (CIRCE1groESL1 and CIRCE2groESL1) in the promoter region of groESL1 and one CIRCE element (CIRCEgroEL2) before groEL2. We also found that negative HrcA and positive ?32 regulators coordinated the transcription of duplicate groELs, and that the double deletion in DK1622 eliminated transcriptional differences and reduced the heat-shock responses of groELs. In vitro binding assays showed that HrcA protein binding was biased towards CIRCE1groESL1, followed by CIRCEgroEL2, but that HrcA proteins failed to bind with CIRCE2groESL1. Mutation experiments revealed that single-nucleotide mutations in the inverted repeat regions changed the HrcA-binding abilities of CIRCEs. We constructed an in vivo transcription-regulation system in Escherichia coli to pair each of the regulators with a groEL promoter. The results indicated that the transcriptional regulation performed by HrcA and ?32 was biased towards the groEL2 and groEL1 promoters, respectively. Based on promoter-sequence characteristics, we proposed a model of the coordinated regulation of the transcription of duplicate groELs in M. xanthus DK1622.
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Affiliation(s)
- Li Zhuo
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Zheng Zhang
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Zhuo Pan
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Duo-Hong Sheng
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Wei Hu
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Yue-Zhong Li
- State Key Laboratory of Microbial Technology, Institute of Microbial Technology, Shandong University, Qingdao 266237, China.
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6
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Kaur N, Seuylemezian A, Patil PP, Patil P, Krishnamurti S, Varelas J, Smith DJ, Mayilraj S, Vaishampayan P. Paenibacillus xerothermodurans sp. nov., an extremely dry heat resistant spore forming bacterium isolated from the soil of Cape Canaveral, Florida. Int J Syst Evol Microbiol 2018; 68:3190-3196. [PMID: 30129919 DOI: 10.1099/ijsem.0.002967] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
A Gram-stain-positive, motile, endospore-producing, facultative anaerobic bacterial strain, designated ATCC 27380T, was isolated from heat-stressed soil of Cape Canaveral, Florida, USA. Growth was observed at 20-42 °C (optimum, 37 °C), at pH 6.0-10.0 (optimum pH 7.0) and in the presence of 0.5-3 % NaCl (optimum 0.5 %). The cell wall contained meso-diaminopimelic acid as the diagnostic amino acid and the isoprenoid quinone was MK-7. The polar lipids present were phosphatidylglycerol, phosphatidylethanolamine, diphosphatidylglycerol and one unknown phospholipid. The main fatty acids were iso-C15 : 0 and anteiso-C15 : 0. Phylogenetic analysis based on 16S rRNA gene sequencing affiliated strain ATCC 27380T to the genus Paenibacillus, and showed the highest sequence similarity to Paenibacillus rigui JCM 16352T (97.0 %). The other closely related type strains exhibited 16S rRNA gene sequence similarity values below 95.9 %. The draft genome of ATCC 27380T had a size of 4,361,187 bases, with a G+C content of 51.0 %. The average nucleotide identity and in silico DNA-DNA hybridization values between strain ATCC 27380T and P. rigui JCM 16352T were 72.5% and 18.5 %, respectively, which were below the threshold suggested for species differentiation (96% and 70 %, respectively). The average amino acid identity between strain ATCC 27380T and P. rigui JCM 16352T was 68.72 %, which was above the suggested genus level demarcation of 65 %. Based on phenotypic, genotypic and chemotaxonomic data, strain ATCC 27380T represents a novel species in the genus Paenibacillus, for which the name Paenibacillusxerothermodurans sp. nov. (=DSM 520T=NRRL NRS-1629T=ATCC 27380T) is proposed.
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Affiliation(s)
- Navjot Kaur
- 1Microbial Type Culture Collection and Gene Bank (MTCC), Institute of Microbial Technology, Chandigarh 160 036, India
| | - Arman Seuylemezian
- 2Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
| | - Prashant P Patil
- 3Bacterial Genomics & Evolution Lab, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India
| | - Prabhu Patil
- 3Bacterial Genomics & Evolution Lab, CSIR-Institute of Microbial Technology, Chandigarh 160 036, India
| | - Srinivasan Krishnamurti
- 1Microbial Type Culture Collection and Gene Bank (MTCC), Institute of Microbial Technology, Chandigarh 160 036, India
| | - Joseph Varelas
- 4Universities Space Research Association, NASA Ames Research Center, Moffett Field, California, 94035, USA
| | - David J Smith
- 5NASA, Space Biosciences Research Branch, NASA Ames Research Center, Moffett Field, California, 94035, USA
| | - Shanmugam Mayilraj
- 1Microbial Type Culture Collection and Gene Bank (MTCC), Institute of Microbial Technology, Chandigarh 160 036, India
| | - Parag Vaishampayan
- 2Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109, USA
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Roncarati D, Scarlato V. Regulation of heat-shock genes in bacteria: from signal sensing to gene expression output. FEMS Microbiol Rev 2017; 41:549-574. [PMID: 28402413 DOI: 10.1093/femsre/fux015] [Citation(s) in RCA: 104] [Impact Index Per Article: 14.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 03/14/2017] [Indexed: 02/07/2023] Open
Abstract
The heat-shock response is a mechanism of cellular protection against sudden adverse environmental growth conditions and results in the prompt production of various heat-shock proteins. In bacteria, specific sensory biomolecules sense temperature fluctuations and transduce intercellular signals that coordinate gene expression outputs. Sensory biomolecules, also known as thermosensors, include nucleic acids (DNA or RNA) and proteins. Once a stress signal is perceived, it is transduced to invoke specific molecular mechanisms controlling transcription of genes coding for heat-shock proteins. Transcriptional regulation of heat-shock genes can be under either positive or negative control mediated by dedicated regulatory proteins. Positive regulation exploits specific alternative sigma factors to redirect the RNA polymerase enzyme to a subset of selected promoters, while negative regulation is mediated by transcriptional repressors. Interestingly, while various bacteria adopt either exclusively positive or negative mechanisms, in some microorganisms these two opposite strategies coexist, establishing complex networks regulating heat-shock genes. Here, we comprehensively summarize molecular mechanisms that microorganisms have adopted to finely control transcription of heat-shock genes.
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Affiliation(s)
- Davide Roncarati
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
| | - Vincenzo Scarlato
- Department of Pharmacy and Biotechnology (FaBiT), University of Bologna, 40126 Bologna, Italy
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8
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A Chlamydia-specific C-terminal region of the stress response regulator HrcA modulates its repressor activity. J Bacteriol 2011; 193:6733-41. [PMID: 21965565 DOI: 10.1128/jb.05792-11] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Chlamydial heat shock proteins have important roles in Chlamydia infection and immunopathogenesis. Transcription of chlamydial heat shock genes is controlled by the stress response regulator HrcA, which binds to its cognate operator CIRCE, causing repression by steric hindrance of RNA polymerase. All Chlamydia spp. encode an HrcA protein that is larger than other bacterial orthologs because of an additional, well-conserved C-terminal region. We found that this unique C-terminal tail decreased HrcA binding to CIRCE in vitro as well as HrcA-mediated transcriptional repression in vitro and in vivo. When we isolated HrcA from chlamydiae, we only detected the full-length protein, but we found that endogenous HrcA had a higher binding affinity for CIRCE than recombinant HrcA. To examine this difference further, we tested the effect of the heat shock protein GroEL on the function of HrcA since endogenous chlamydial HrcA has been previously shown to associate with GroEL as a complex. GroEL enhanced the ability of HrcA to bind CIRCE and to repress transcription in vitro, but this stimulatory effect was greater on full-length HrcA than HrcA lacking the C-terminal tail. These findings demonstrate that the novel C-terminal tail of chlamydial HrcA is an inhibitory region and provide evidence that its negative effect on repressor function can be counteracted by GroEL. These results support a model in which GroEL functions as a corepressor that interacts with HrcA to regulate chlamydial heat shock genes.
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Kwon HY, Kim EH, Tran TDH, Pyo SN, Rhee DK. Reduction-sensitive and cysteine residue-mediated Streptococcus pneumoniae HrcA oligomerization in vitro. Mol Cells 2009; 27:149-57. [PMID: 19277496 DOI: 10.1007/s10059-009-0019-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Revised: 10/31/2008] [Accepted: 11/19/2008] [Indexed: 01/16/2023] Open
Abstract
In both gram-positive and several gram-negative bacteria, the transcription of dnaK and groE operons is negatively regulated by HrcA; however, the mechanism modulating HrcA protein activity upon thermal stress remains elusive. Here, we demonstrate that HrcA is modulated via reduction and oligomerization in vitro. Native-PAGE analysis was used to reveal the oligomeric structure of HrcA. The oligomeric HrcA structure became monomeric following treatment with the reducing agent dithothreitol, and this process was reversed by treatment with hydrogen peroxide. Moreover, the mutant HrcA C118S exhibited reduced binding to CIRCE elements and became less oligomerized, suggesting that cysteine residue 118 is important for CIRCE element binding as well as oligomerization. Conversely, HrcA mutant C280S exhibited increased oligomerization. An HrcA double mutant (C118S, C280S) was monomeric and exhibited a level of oligomerization and CIRCE binding similar to wild type HrcA, suggesting that cysteine residues 118 and 280 may function as checks to one another during oligomer formation. Biochemical fractionation of E. coli cells overexpressing HrcA revealed the presence of HrcA in the membrane fraction. Together, these results suggest that the two HrcA cysteine residues at positions 118 and 280 function as reduction sensors in the membrane and mediate oligomerization upon stress.
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Affiliation(s)
- Hyog-Young Kwon
- College of Pharmacy, Sungkyunkwan University, Suwon, 440-746, Korea
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10
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Chan YC, Raengpradub S, Boor KJ, Wiedmann M. Microarray-based characterization of the Listeria monocytogenes cold regulon in log- and stationary-phase cells. Appl Environ Microbiol 2007; 73:6484-98. [PMID: 17720827 PMCID: PMC2075049 DOI: 10.1128/aem.00897-07] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Whole-genome microarray experiments were performed to define the Listeria monocytogenes cold growth regulon and to identify genes differentially expressed during growth at 4 and 37 degrees C. Microarray analysis using a stringent cutoff (adjusted P < 0.001; >/=2.0-fold change) revealed 105 and 170 genes that showed higher transcript levels in logarithmic- and stationary-phase cells, respectively, at 4 degrees C than in cells grown at 37 degrees C. A total of 74 and 102 genes showed lower transcript levels in logarithmic- and stationary-phase cells, respectively, grown at 4 degrees C. Genes with higher transcript levels at 4 degrees C in both stationary- and log-phase cells included genes encoding a two-component response regulator (lmo0287), a cold shock protein (cspL), and two RNA helicases (lmo0866 and lmo1722), whereas a number of genes encoding virulence factors and heat shock proteins showed lower transcript levels at 4 degrees C. Selected genes that showed higher transcript levels at 4 degrees C during both stationary and log phases were confirmed by quantitative reverse transcriptase PCR. Our data show that (i) a large number of L. monocytogenes genes are differentially expressed at 4 and 37 degrees C, with more genes showing higher transcript levels than lower transcript levels at 4 degrees C, (ii) L. monocytogenes genes with higher transcript levels at 4 degrees C include a number of genes and operons with previously reported or plausible roles in cold adaptation, and (iii) L. monocytogenes genes with lower transcript levels at 4 degrees C include a number of virulence and virulence-associated genes as well as some heat shock genes.
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Affiliation(s)
- Yvonne C Chan
- Department of Food Science, Cornell University, Ithica, NY 14853, USA.
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Kojima K, Nakamoto H. A novel light- and heat-responsive regulation of thegroEtranscription in the absence of HrcA or CIRCE in cyanobacteria. FEBS Lett 2007; 581:1871-80. [PMID: 17434494 DOI: 10.1016/j.febslet.2007.03.084] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2007] [Revised: 03/23/2007] [Accepted: 03/27/2007] [Indexed: 11/26/2022]
Abstract
The inactivation of the hrcA gene resulted in de-repression of the two CIRCE-containing groE genes in a cyanobacterium Synechocystis sp. strain PCC6803, indicating that the CIRCE operator/HrcA repressor system operates in the cyanobacterium. We found that the groE expression in the hrcA mutant is greatly induced by heat and/or light. Removal of a K-box containing and an N-box containing region upstream of the groESL1 promoter abolished light-induced transcription of a luxAB reporter gene fused with the groESL1 promoter. Similar sequences to the K-box, GTTCGG-NNAN-CCNNAC, were also found upstream of the dnaK2 genes. A specific binding of a protein(s) to the N-box, GATCTA, was detected by a gel mobility shift assay with using cell extracts. We propose that the cyanobacterial groEL expression is regulated by a putative positive mechanism mediated by these novel elements in addition to the HrcA/CIRCE system. The groEL2 genes from Synechococcus sp. strain PCC 7942 and Thermosynechococcus elongatus, which lack CIRCE, K-box, and N-box naturally, were also induced by heat and/or light, indicating that the control mechanism of the unique light-responsive groE expression is highly diversified in cyanobacteria.
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Affiliation(s)
- Kouji Kojima
- Department of Biochemistry and Molecular Biology, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570, Japan
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Roncarati D, Spohn G, Tango N, Danielli A, Delany I, Scarlato V. Expression, purification and characterization of the membrane-associated HrcA repressor protein of Helicobacter pylori. Protein Expr Purif 2007; 51:267-75. [PMID: 16997572 DOI: 10.1016/j.pep.2006.08.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 08/03/2006] [Accepted: 08/06/2006] [Indexed: 11/22/2022]
Abstract
Helicobacter pylori, a microaerophilic, gram-negative bacterium is a human pathogen that colonizes the gastric niche and is associated with several acute and chronic stomach diseases. In order to survive in the gastric environment and become pathogenic, the bacterium relies on a plethora of virulence factors, which also include heat shock proteins. We previously showed that two out of the three operons encoding the major cellular chaperone machineries are transcriptionally repressed by two regulators, HrcA and HspR. Till now, molecular studies aimed at the understanding of the role of each protein in controlling transcription was hampered by toxicity and insolubility of HrcA in heterologous expression systems. Similar problems were encountered by many other groups studying HrcA from different bacteria. In this study, we analyzed the amino acid sequence of HrcA that predicted association of this protein to the inner membrane, which was experimentally verified. Subsequently, we implemented a dedicated induction protocol which enabled the overexpression of the recombinant His-HrcA protein in the soluble fraction of Escherichia coli cells. Moreover, we developed a purification procedure for His-HrcA that allowed us to obtain highly pure preparation of the protein. The functionality of the purified protein was then confirmed with an in vitro DNA-binding assay.
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Affiliation(s)
- Davide Roncarati
- Department of Biology, University of Bologna, Via Selmi 3, 40126 Bologna, Italy
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Conners SB, Mongodin EF, Johnson MR, Montero CI, Nelson KE, Kelly RM. Microbial biochemistry, physiology, and biotechnology of hyperthermophilic Thermotoga species. FEMS Microbiol Rev 2006; 30:872-905. [PMID: 17064285 DOI: 10.1111/j.1574-6976.2006.00039.x] [Citation(s) in RCA: 90] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
High-throughput sequencing of microbial genomes has allowed the application of functional genomics methods to species lacking well-developed genetic systems. For the model hyperthermophile Thermotoga maritima, microarrays have been used in comparative genomic hybridization studies to investigate diversity among Thermotoga species. Transcriptional data have assisted in prediction of pathways for carbohydrate utilization, iron-sulfur cluster synthesis and repair, expolysaccharide formation, and quorum sensing. Structural genomics efforts aimed at the T. maritima proteome have yielded hundreds of high-resolution datasets and predicted functions for uncharacterized proteins. The information gained from genomics studies will be particularly useful for developing new biotechnology applications for T. maritima enzymes.
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Affiliation(s)
- Shannon B Conners
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, NC 27695-7905, USA
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Liu J, Huang C, Shin DH, Yokota H, Jancarik J, Kim JS, Adams PD, Kim R, Kim SH. Crystal Structure of a Heat-inducible Transcriptional Repressor HrcA from Thermotoga maritima: Structural Insight into DNA Binding and Dimerization. J Mol Biol 2005; 350:987-96. [PMID: 15979091 DOI: 10.1016/j.jmb.2005.04.021] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2005] [Revised: 04/08/2005] [Accepted: 04/12/2005] [Indexed: 11/24/2022]
Abstract
All cells have a defense mechanism against a sudden heat-shock stress. Commonly, they express a set of proteins that protect cellular proteins from being denatured by heat. Among them, GroE and DnaK chaperones are representative defending systems, and their transcription is regulated by a heat-shock repressor protein HrcA. HrcA repressor controls the transcription of groE and dnaK operons by binding the palindromic CIRCE element, presumably as a dimer, and the activity of HrcA repressor is modulated by GroE chaperones. Here, we report the first crystal structure of a heat-inducible transcriptional repressor, HrcA, from Thermotoga maritima at 2.2A resolution. The Tm_HrcA protein crystallizes as a dimer. The monomer is composed of three domains: an N-terminal winged helix-turn-helix domain (WH), a GAF-like domain, and an inserted dimerizing domain (IDD). The IDD shows a unique structural fold with an anti-parallel beta-sheet composed of three beta-strands sided by four alpha-helices. The Tm_HrcA dimer structure is formed through hydrophobic contact between the IDDs and a limited contact that involves conserved residues between the GAF-like domains. In the overall dimer structure, the two WH domains are exposed, but the conformation of these two domains seems to be incompatible with DNA binding. We suggest that our structure may represent an inactive form of the HrcA repressor. Structural implication on how the inactive form of HrcA may be converted to the active form by GroEL binding to a conserved C-terminal sequence region of HrcA is discussed.
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Affiliation(s)
- Jinyu Liu
- Berkeley Structural Genomics Center, Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
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