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Fecht S, Paracuellos P, Subramoni S, Tan CAZ, Ilangovan A, Costa TRD, Filloux A. Functionality of chimeric TssA proteins in the type VI secretion system reveals sheath docking specificity within their N-terminal domains. Nat Commun 2024; 15:4283. [PMID: 38769318 PMCID: PMC11106082 DOI: 10.1038/s41467-024-48487-8] [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: 03/19/2023] [Accepted: 05/01/2024] [Indexed: 05/22/2024] Open
Abstract
The genome of Pseudomonas aeruginosa encodes three type VI secretion systems, each comprising a dozen distinct proteins, which deliver toxins upon T6SS sheath contraction. The least conserved T6SS component, TssA, has variations in size which influence domain organisation and structure. Here we show that the TssA Nt1 domain interacts directly with the sheath in a specific manner, while the C-terminus is essential for oligomerisation. We built chimeric TssA proteins by swapping C-termini and showed that these can be functional even when made of domains from different TssA sub-groups. Functional specificity requires the Nt1 domain, while the origin of the C-terminal domain is more permissive for T6SS function. We identify two regions in short TssA proteins, loop and hairpin, that contribute to sheath binding. We propose a docking mechanism of TssA proteins with the sheath, and a model for how sheath assembly is coordinated by TssA proteins from this position.
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Affiliation(s)
- Selina Fecht
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Patricia Paracuellos
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Sujatha Subramoni
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore
| | - Casandra Ai Zhu Tan
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore
| | - Aravindan Ilangovan
- School of Biological and Behavioural Sciences, Queen Mary University of London, London, E1 4NS, UK
| | - Tiago R D Costa
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Alain Filloux
- CBRB Centre for Bacterial Resistance Biology, Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK.
- Singapore Centre for Environmental Life Sciences Engineering, Nanyang Technological University, Singapore, 637551, Singapore.
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2
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Du X, Kang M, Yang C, Yao X, Zheng L, Wu Y, Zhang P, Zhang H, Zhou Y, Sun Y. Construction and analysis of the immune effect of two different vaccine types based on Vibrio harveyi VgrG. FISH & SHELLFISH IMMUNOLOGY 2024; 148:109494. [PMID: 38499217 DOI: 10.1016/j.fsi.2024.109494] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2023] [Revised: 02/13/2024] [Accepted: 03/07/2024] [Indexed: 03/20/2024]
Abstract
Vibrio harveyi poses a significant threat to fish and invertebrates in mariculture, resulting in substantial financial repercussions for the aquaculture sector. Valine-glycine repeat protein G (VgrG) is essential for the type VI secretion system's (T6SS) assembly and secretion. VgrG from V. harveyi QT520 was cloned and analyzed in this study. The localization of VgrG was determined by Western blot, which revealed that it was located in the cytoplasm, secreted extracellularly, and attached to the membrane. The effectiveness of two vaccinations against V. harveyi infection-a subunit vaccine (rVgrG) and a DNA vaccine (pCNVgrG) prepared with VgrG was evaluated. The findings indicated that both vaccines provided a degree of protection against V. harveyi challenge. At 4 weeks post-vaccination (p.v.), the rVgrG and pCNVgrG exhibited relative percent survival rates (RPS) of 71.43% and 76.19%, respectively. At 8 weeks p.v., the RPS for rVgrG and pCNVgrG were 68.21% and 72.71%, respectively. While both rVgrG and pCNVgrG elicited serum antibody production, the subunit vaccinated fish demonstrated significantly higher levels of serum anti-VgrG specific antibodies than the DNA vaccine group. The result of qRT-PCR demonstrated that the expression of major histocompatibility complex (MHC) class Iα, tumor necrosis factor-alpha (TNF-α), interferon γ (IFNγ), and cluster of differentiation 4 (CD4) were up-regulated by both rVgrG and pCNVgrG. Fish vaccinated with rVgrG and pCNVgrG exhibited increased activity of acid phosphatase, alkaline phosphatase, superoxide dismutase, and lysozyme. These findings suggest that VgrG from V. harveyi holds potential for application in vaccination.
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Affiliation(s)
- Xiangyu Du
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Minjie Kang
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Chunhuan Yang
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Xinping Yao
- Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Lvliang Zheng
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China
| | - Ying Wu
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Panpan Zhang
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Han Zhang
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Yongcan Zhou
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China
| | - Yun Sun
- School of Breeding and Multiplication (Sanya Institute of Breeding and Multiplication), Hainan University, Sanya, 572025, China; Collaborative Innovation Center of Marine Science and Technology, Hainan University, Haikou, 570228, China; School of Marine Biology and Fisheries, Hainan University, Haikou 570228, China.
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3
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Zhao X, Gao L, Ali Q, Yu C, Yuan B, Huang H, Long J, Gu Q, Wu H, Gao X. A type VI secretion system effector TseG of Pantoea ananatis is involved in virulence and antibacterial activity. MOLECULAR PLANT PATHOLOGY 2024; 25:e13442. [PMID: 38476100 DOI: 10.1111/mpp.13442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2023] [Revised: 01/14/2024] [Accepted: 02/16/2024] [Indexed: 03/14/2024]
Abstract
The type VI secretion system (T6SS) of many gram-negative bacteria injects toxic effectors into adjacent cells to manipulate host cells during pathogenesis or to kill competing bacteria. However, the identification and function of the T6SS effectors remains only partly known. Pantoea ananatis, a gram-negative bacterium, is commonly found in various plants and natural environments, including water and soil. In the current study, genomic analysis of P. ananatis DZ-12 causing brown stalk rot on maize demonstrated that it carries three T6SS gene clusters, namely, T6SS-1, T6SS-2, and T6SS-3. Interestingly, only T6SS-1 secretion systems are involved in pathogenicity and bacterial competition. The study also investigated the T6SS-1 system in detail and identified an unknown T6SS-1-secreted effector TseG by using the upstream T6SS effector chaperone TecG containing a conserved domain of DUF2169. TseG can directly interact with the chaperone TecG for delivery and with a downstream immunity protein TsiG for protection from its toxicity. TseG, highly conserved in the Pantoea genus, is involved in virulence in maize, potato, and onion. Additionally, P. ananatis uses TseG to target Escherichia coli, gaining a competitive advantage. This study provides the first report on the T6SS-1-secreted effector from P. ananatis, thereby enriching our understanding of the various types and functions of type VI effector proteins.
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Affiliation(s)
- Xiaozhen Zhao
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Lu Gao
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Qurban Ali
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Chenjie Yu
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Bingqin Yuan
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Hai Huang
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Juying Long
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Qin Gu
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Huijun Wu
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
| | - Xuewen Gao
- Key Laboratory of Monitoring and Management of Crop Disease and Pest Insects, College of Plant Protection, Nanjing Agricultural University, Ministry of Education, Nanjing, China
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Ramamoorthy S, Pena M, Ghosh P, Liao YY, Paret M, Jones JB, Potnis N. Transcriptome profiling of type VI secretion system core gene tssM mutant of Xanthomonas perforans highlights regulators controlling diverse functions ranging from virulence to metabolism. Microbiol Spectr 2024; 12:e0285223. [PMID: 38018859 PMCID: PMC10782981 DOI: 10.1128/spectrum.02852-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2023] [Accepted: 10/20/2023] [Indexed: 11/30/2023] Open
Abstract
IMPORTANCE T6SS has received attention due to its significance in mediating interorganismal competition through contact-dependent release of effector molecules into prokaryotic and eukaryotic cells. Reverse-genetic studies have indicated the role of T6SS in virulence in a variety of plant pathogenic bacteria, including the one studied here, Xanthomonas. However, it is not clear whether such effect on virulence is merely due to a shift in the microbiome-mediated protection or if T6SS is involved in a complex virulence regulatory network. In this study, we conducted in vitro transcriptome profiling in minimal medium to decipher the signaling pathways regulated by tssM-i3* in X. perforans AL65. We show that TssM-i3* regulates the expression of a suite of genes associated with virulence and metabolism either directly or indirectly by altering the transcription of several regulators. These findings further expand our knowledge on the intricate molecular circuits regulated by T6SS in phytopathogenic bacteria.
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Affiliation(s)
- Sivakumar Ramamoorthy
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Michelle Pena
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Palash Ghosh
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
| | - Ying-Yu Liao
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Mathews Paret
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Jeffrey B. Jones
- Department of Plant Pathology, University of Florida, Gainesville, Florida, USA
| | - Neha Potnis
- Department of Entomology and Plant Pathology, Auburn University, Auburn, Alabama, USA
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5
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Diepold A. Defining Assembly Pathways by Fluorescence Microscopy. Methods Mol Biol 2024; 2715:383-394. [PMID: 37930541 DOI: 10.1007/978-1-0716-3445-5_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2023]
Abstract
Bacterial secretion systems are among the largest protein complexes in prokaryotes and display remarkably complex architectures. Their assembly often follows clearly defined pathways. Deciphering these pathways not only reveals how bacteria accomplish to build these large functional complexes but can provide crucial information on the interactions and subcomplexes within secretion systems, their distribution within the bacterium, and even functional insights. Fluorescence microscopy provides a powerful tool for biological imaging, which presents an interesting method to accurately define the biogenesis of macromolecular complexes using fluorescently labeled components. Here, I describe the use of this method to decipher the assembly pathway of bacterial secretion systems.
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Affiliation(s)
- Andreas Diepold
- Department of Ecophysiology, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany.
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Anderson AJG, Morrell B, Lopez Campos G, Valvano MA. Distribution and diversity of type VI secretion system clusters in Enterobacter bugandensis and Enterobacter cloacae. Microb Genom 2023; 9:001148. [PMID: 38054968 PMCID: PMC10763514 DOI: 10.1099/mgen.0.001148] [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: 09/06/2023] [Accepted: 11/16/2023] [Indexed: 12/07/2023] Open
Abstract
Gram-negative bacteria use type VI secretion systems (T6SSs) to antagonize neighbouring cells. Although primarily involved in bacterial competition, the T6SS is also implicated in pathogenesis, biofilm formation and ion scavenging. Enterobacter species belong to the ESKAPE pathogens, and while their antibiotic resistance has been well studied, less is known about their pathogenesis. Here, we investigated the distribution and diversity of T6SS components in isolates of two clinically relevant Enterobacter species, E. cloacae and E. bugandensis. T6SS clusters are grouped into four types (T6SSi-T6SSiv), of which type i can be further divided into six subtypes (i1, i2, i3, i4a, i4b, i5). Analysis of a curated dataset of 31 strains demonstrated that most of them encode T6SS clusters belonging to the T6SSi type. All T6SS-positive strains possessed a conserved i3 cluster, and many harboured one or two additional i2 clusters. These clusters were less conserved, and some strains displayed evidence of deletion. We focused on a pathogenic E. bugandensis clinical isolate for comprehensive in silico effector prediction, with comparative analyses across the 31 isolates. Several new effector candidates were identified, including an evolved VgrG with a metallopeptidase domain and a Tse6-like protein. Additional effectors included an anti-eukaryotic catalase (KatN), M23 peptidase, PAAR and VgrG proteins. Our findings highlight the diversity of Enterobacter T6SSs and reveal new putative effectors that may be important for the interaction of these species with neighbouring cells and their environment.
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Affiliation(s)
- Amy J. G. Anderson
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
| | - Becca Morrell
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
| | - Guillermo Lopez Campos
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
| | - Miguel A. Valvano
- Wellcome-Wolfson Institute for Experimental Medicine, Queen’s University Belfast, Belfast, BT9 7BL, UK
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7
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Liu W, Li M, Cao S, Ishaq HM, Zhao H, Yang F, Liu L. The Biological and Regulatory Role of Type VI Secretion System of Klebsiella pneumoniae. Infect Drug Resist 2023; 16:6911-6922. [PMID: 37928603 PMCID: PMC10624183 DOI: 10.2147/idr.s426657] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2023] [Accepted: 09/30/2023] [Indexed: 11/07/2023] Open
Abstract
Bacteria communicate with their surroundings through diverse secretory systems, and the recently discovered Type VI Secretion System (T6SS) has gained significant attention. Klebsiella pneumoniae (K. pneumoniae), an opportunistic pathogen known for causing severe infections in both hospital and animal settings, possesses this intriguing T6SS. This system equips K. pneumoniae with a formidable armory of protein-based weaponry, enabling the delivery of toxins into neighboring cells, thus granting a substantial competitive advantage. Remarkably, the T6SS has also been associated with K. pneumoniae's ability to form biofilms and acquire resistance against antibiotics. However, the precise effects of the T6SS on K. pneumoniae's functions remain inadequately studied, despite research efforts to understand the intricacies of these mechanisms. This comprehensive review aims to provide an overview of the current knowledge regarding the biological functions and regulatory mechanisms of the T6SS in K. pneumoniae.
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Affiliation(s)
- Wenke Liu
- Department of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, People’s Republic of China
| | - Min Li
- Department of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, People’s Republic of China
| | - Shiwen Cao
- Department of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, People’s Republic of China
| | - Hafiz Muhammad Ishaq
- Faculty of Veterinary and Animal Sciences, Muhammad Nawaz Shareef University of Agriculture, Multan, Pakistan
| | - Huajie Zhao
- Department of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, People’s Republic of China
| | - Fan Yang
- Department of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, People’s Republic of China
| | - Liang Liu
- Department of Pathogenic Biology, School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, People’s Republic of China
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Mathieu-Denoncourt A, Duperthuy M. The VxrAB two-component system is important for the polymyxin B-dependent activation of the type VI secretion system in Vibrio cholerae O1 strain A1552. Can J Microbiol 2023; 69:393-406. [PMID: 37343290 DOI: 10.1139/cjm-2023-0026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/23/2023]
Abstract
The type VI secretion system (T6SS) is used by bacteria for virulence, resistance to grazing, and competition with other bacteria. We previously demonstrated that the role of the T6SS in interbacterial competition and in resistance to grazing is enhanced in Vibrio cholerae in the presence of subinhibitory concentrations of polymyxin B. Here, we performed a global quantitative proteomic analysis and a targeted transcriptomic analysis of the T6SS-known regulators in V. cholerae grown with and without polymyxin B. The proteome of V. cholerae is greatly modified by polymyxin B with more than 39% of the identified cellular proteins displaying a difference in their abundance, including T6SS-related proteins. We identified a regulator whose abundance and expression are increased in the presence of polymyxin B, vxrB, the response regulator of the two-component system VxrAB (VCA0565-66). In vxrAB, vxrA and vxrB deficient mutants, the expression of both hcp copies (VC1415 and VCA0017), although globally reduced, was not modified by polymyxin B. These hcp genes encode an identical protein Hcp, which is the major component of the T6SS syringe. Thus, the upregulation of the T6SS in the presence of polymyxin B appears to be, at least in part, due to the two-component system VxrAB.
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Affiliation(s)
- Annabelle Mathieu-Denoncourt
- Département de Microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada
| | - Marylise Duperthuy
- Département de Microbiologie, infectiologie et immunologie, Faculté de médecine, Université de Montréal, Montréal, QC, Canada
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9
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Hespanhol JT, Nóbrega-Silva L, Bayer-Santos E. Regulation of type VI secretion systems at the transcriptional, posttranscriptional and posttranslational level. MICROBIOLOGY (READING, ENGLAND) 2023; 169:001376. [PMID: 37552221 PMCID: PMC10482370 DOI: 10.1099/mic.0.001376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2023] [Accepted: 07/25/2023] [Indexed: 08/09/2023]
Abstract
Bacteria live in complex polymicrobial communities and are constantly competing for resources. The type VI secretion system (T6SS) is a widespread antagonistic mechanism used by Gram-negative bacteria to gain an advantage over competitors. T6SSs translocate toxic effector proteins inside target prokaryotic cells in a contact-dependent manner. In addition, some T6SS effectors can be secreted extracellularly and contribute to the scavenging scarce metal ions. Bacteria deploy their T6SSs in different situations, categorizing these systems into offensive, defensive and exploitative. The great variety of bacterial species and environments occupied by such species reflect the complexity of regulatory signals and networks that control the expression and activation of the T6SSs. Such regulation is tightly controlled at the transcriptional, posttranscriptional and posttranslational level by abiotic (e.g. pH, iron) or biotic (e.g. quorum-sensing) cues. In this review, we provide an update on the current knowledge about the regulatory networks that modulate the expression and activity of T6SSs across several species, focusing on systems used for interbacterial competition.
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Affiliation(s)
- Julia Takuno Hespanhol
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo 05508-900, Brazil
| | - Luize Nóbrega-Silva
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo 05508-900, Brazil
| | - Ethel Bayer-Santos
- Department of Microbiology, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo 05508-900, Brazil
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10
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Sun J, Su H, Zhang W, Luo X, Li R, Liu M. Comparative genomics revealed that Vibrio furnissii and Vibrio fluvialis have mutations in genes related to T6SS1 and T6SS2. Arch Microbiol 2023; 205:207. [PMID: 37101014 DOI: 10.1007/s00203-023-03557-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 04/13/2023] [Accepted: 04/17/2023] [Indexed: 04/28/2023]
Abstract
The type VI secretion system (T6SS) is important for interbacterial competition and virulence in Vibrio species. It is generally agreed that T6SS provides a fitness advantage to Vibrios. Some Vibrio species possess one, while others possess two T6SSs. Even within the same Vibrio species, different strains can harbor a variable number of T6SSs. Such is the case in V. fluvialis, an opportunistic human pathogen, that some V. fluvialis strains do not harbor T6SS1. This study found that Amphritea, Marinomonas, Marinobacterium, Vibrio, Photobacterium, and Oceanospirillum species have genes encoding V. fluvialis T6SS1 homologs. The cladogram of T6SS1 genes suggested that these genes appeared to be horizontally acquired by V. fluvialis, V. furnissii, and some other Vibrio species, when compared with the species tree. Codon insertions, codon deletions, nonsense mutations, and the insertion sequence are found in many genes, such as clpV1, tssL1, and tssF1, which encode structure components of T6SS1 in V. furnissii and V. fluvialis. Codon deletion events are more common than codon insertion, insertion sequence disruption, and nonsense mutation events in genes that encode components of T6SS1. Similarly, codon insertions and codon deletions are found in genes relevant to T6SS2, including tssM2, vgrG2 and vasH, in V. furnissii and V. fluvialis. These mutations are likely to disable the functions of T6SSs. Our findings indicate that T6SS may have a fitness disadvantage in V. furnissii and V. fluvialis, and the loss of function in T6SS may help these Vibrio species to survive under certain conditions.
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Affiliation(s)
- Jiakai Sun
- College of Oceanography, Hohai University, Nanjing, China
| | - Haochen Su
- College of Oceanography, Hohai University, Nanjing, China
| | - Wenhui Zhang
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu Province, China
| | - Xuesong Luo
- State Key Laboratory of Agricultural Microbiology, College of Resources of Environment, Huazhong Agricultural University, Wuhan, China
| | - Ruichao Li
- Jiangsu Co-Innovation Center for Prevention and Control of Important Animal Infectious Diseases and Zoonoses, College of Veterinary Medicine, Yangzhou University, Yangzhou, China.
- Institute of Comparative Medicine, Yangzhou University, Yangzhou, Jiangsu Province, China.
| | - Ming Liu
- Department of Clinical Laboratory, Shenzhen Third People's Hospital, Second Hospital Affiliated to Southern University of Science and Technology, National Clinical Research Center for Infectious Diseases, Shenzhen, 518055, Guangdong Province, P. R. China.
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11
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VgrG Spike Dictates PAAR Requirement for the Assembly of the Type VI Secretion System. J Bacteriol 2023; 205:e0035622. [PMID: 36655996 PMCID: PMC9945574 DOI: 10.1128/jb.00356-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Widely employed by Gram-negative pathogens for competition and pathogenesis, the type six protein secretion system (T6SS) can inject toxic effectors into neighboring cells through the penetration of a spear-like structure comprising a long Hcp tube and a VgrG-PAAR spike complex. The cone-shaped PAAR is believed to sharpen the T6SS spear for penetration but it remains unclear why PAAR is required for T6SS functions in some bacteria but dispensable in others. Here, we report the conditional requirement of PAAR for T6SS functions in Aeromonas dhakensis, an emerging human pathogen that may cause severe bacteremia. By deleting the two PAAR paralogs, we show that PAAR is not required for T6SS secretion, bacterial killing, or specific effector delivery in A. dhakensis. By constructing combinatorial PAAR and vgrG deletions, we demonstrate that deletion of individual PAAR moderately reduced T6SS functions but double or triple deletions of PAAR in the vgrG deletion mutants severely impaired T6SS functions. Notably, the auxiliary-cluster-encoded PAAR2 and VgrG3 are less critical than the main-cluster-encoded PAAR1 and VgrG1&2 proteins to T6SS functions. In addition, PAAR1 but not PAAR2 contributes to antieukaryotic virulence in amoeba. Our data suggest that, for a multi-PAAR T6SS, the variable role of PAAR paralogs correlates with the VgrG-spike composition that collectively dictates T6SS assembly. IMPORTANCE Gram-negative bacteria often encode multiple paralogs of the cone-shaped PAAR that sits atop the VgrG-spike and is thought to sharpen the spear-like T6SS puncturing device. However, it is unclear why PAAR is required for the assembly of some but not all T6SSs and why there are multiple PAARs if they are not required. Our data delineate a VgrG-mediated conditional requirement for PAAR and suggest a core-auxiliary relationship among different PAAR-VgrG modules that may have been acquired sequentially by the T6SS during evolution.
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Type VI Secretion Systems: Environmental and Intra-host Competition of Vibrio cholerae. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2023; 1404:41-63. [PMID: 36792870 DOI: 10.1007/978-3-031-22997-8_3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/17/2023]
Abstract
The Vibrio Type VI Secretion System (T6SS) is a harpoon-like nanomachine that serves as a defense system and is encoded by approximately 25% of all gram-negative bacteria. In this chapter, we describe the structure of the T6SS in different Vibrio species and outline how the use of different T6SS effector and immunity proteins control kin selection. We summarize the genetic loci that encode the structural elements that make up the Vibrio T6SSs and how these gene clusters are regulated. Finally, we provide insights into T6SS-based competitive dynamics, the role of T6SS genetic exchange in those competitive dynamics, and roles for the Vibrio T6SS in virulence.
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Heterologous Assembly of the Type VI Secretion System Empowers Laboratory Escherichia coli with Antimicrobial and Cell Penetration Capabilities. Appl Environ Microbiol 2022; 88:e0130522. [PMID: 36154120 DOI: 10.1128/aem.01305-22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The synthetic biology toolbox has amassed a vast number of diverse functional modules, but protein translocation modules for cell penetration and cytosol-to-cytosol delivery remain relatively scarce. The type VI secretion system (T6SS), commonly found in many Gram-negative pathogens, functions as a contractile device to translocate protein toxins to prokaryotic and eukaryotic cells. Here, we have assembled the T6SS of Aeromonas dhakensis, an opportunistic waterborne pathogen, in the common laboratory strain Escherichia coli BL21(DE3). We constructed a series of plasmids (pT6S) carrying the T6SS structural and effector genes under native or tetracycline-inducible promoters, the latter for controlled expression. Using fluorescence microscopy and biochemical analyses, we demonstrate a functional T6SS in E. coli capable of secreting proteins directly into the cytosol of neighboring bacteria and outcompeting a number of drug-resistant pathogens. The heterologous assembly of T6SS not only confers the lab workhorse E. coli with the cytosol-to-cytosol protein delivery capability but also demonstrates the potential for harnessing the T6SS of various pathogens for general protein delivery and antibacterial applications. IMPORTANCE The T6SS is a powerful and versatile protein delivery system. However, the complexity of its macromolecular structure and gene regulation makes it not a trivial task to reconstitute the T6SSs of pathogens in a nonpathogenic host. In this study, we have assembled an inducible T6SS in E. coli BL21(DE3) and demonstrated its functions in protein delivery and antimicrobial activities. The engineered T6SS empowers E. coli to deliver protein cargos into a wide range of prokaryotic and eukaryotic cells.
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Fang L, Zhu H, Geng Y, Zhang G, Zhang H, Shi T, Wu X, Li QX, Hua R. Resistance properties and adaptation mechanism of cadmium in an enriched strain, Cupriavidus nantongensis X1 T. JOURNAL OF HAZARDOUS MATERIALS 2022; 434:128935. [PMID: 35461001 DOI: 10.1016/j.jhazmat.2022.128935] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2022] [Revised: 04/12/2022] [Accepted: 04/12/2022] [Indexed: 06/14/2023]
Abstract
Bacterial adaption to heavy metal stress is a complex and comprehensive process of multi-response regulation. However, the mechanism is largely unexplored. In this study, cadmium (Cd) resistance and adaptation mechanism in Cupriavidus nantongensis X1T were investigated. Strain X1T could resist the stress of 307 mg/L Cd2+ and remove 70% Cd2+ in 48 h. Spectroscopic analyses suggested interactions between Cd2+ with C-N, -COOH, and -NH ligands of extracellular polymeric substances. Whole-genome sequencing found that the resistance of Cd2+ in strain X1T was caused by the joint action of Czc and Cad systems. Cd2+ at 20 mg/L elicited differential expression of 1157 genes in strain X1T. In addition to the reported effects of uptake, adsorption, effluxion, and accumulation system, the oxidative stress system, Type-VI secretory protein system, Fe-S protein synthesis, and cysteine synthesis system in strain X1T were involved in the Cd2+ resistance and accumulation. The intracellular accumulation content of Cd2+ in strain X1T was higher than the extracellular adsorption content made strain X1T to be an important resource strain in the bioremediation of Cd-contaminated sewage. The results provide a theoretical network for understanding the complex regulatory system of bacterial resistance and adaptation of Cd against stressful environments.
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Affiliation(s)
- Liancheng Fang
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China; Institute for Green Development, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Hao Zhu
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Yuehan Geng
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Genrong Zhang
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Houpu Zhang
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China; Institute for Green Development, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Taozhong Shi
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Xiangwei Wu
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China; Institute for Green Development, Anhui Agricultural University, Hefei, Anhui 230036, China
| | - Qing X Li
- Department of Molecular Biosciences and Bioengineering, University of Hawaii at Manoa, 1955 East-West Road, Honolulu, HI 96822, United States
| | - Rimao Hua
- Anhui Provincial Key Laboratory for Quality and Safety of Agri-Products, School of Resource & Environment, Anhui Agricultural University, Hefei, Anhui 230036, China; Institute for Green Development, Anhui Agricultural University, Hefei, Anhui 230036, China.
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Wang G, Fan C, Wang H, Jia C, Li X, Yang J, Zhang T, Gao S, Min X, Huang J. Type VI secretion system-associated FHA domain protein TagH regulates the hemolytic activity and virulence of Vibrio cholerae. Gut Microbes 2022; 14:2055440. [PMID: 35383540 PMCID: PMC8993066 DOI: 10.1080/19490976.2022.2055440] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The type VI secretion system (T6SS) and hemolysin HlyA are important virulence factors in Vibrio cholerae. The forkhead-associated (FHA) domain is a conserved phosphopeptide binding domain that exists in many regulatory modules. The FHA domain protein-encoding gene is conserved in the T6SS gene cluster and regulates the assembly and secretion of the T6SS. This study shows for the first time that the FHA domain protein TagH plays a role in controlling the hemolytic activity of V. cholerae, in addition to regulating the T6SS. TagH negatively regulates HlyA expression at the transcriptional and post-translational levels. The phosphopeptide binding sites of the FHA domain of TagH play a key role in the regulation of hemolytic activity. The deletion of tagH enhances the intestinal pathogenicity and extraintestinal invasion ability of V. cholerae, which mainly depend on the expression of HlyA. This study provides evidence that helps unravel the novel regulatory role of TagH in HlyA and provides critical insights which will aid in the development of strategies to manage HlyA.
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Affiliation(s)
- Guangli Wang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
| | - Chan Fan
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Hui Wang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Chengyi Jia
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Xiaoting Li
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Jianru Yang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Tao Zhang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Song Gao
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China
| | - Xun Min
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China,CONTACT Xun Min Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China
| | - Jian Huang
- Department of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi, Guizhou, China,School of Laboratory Medicine, Zunyi Medical University, Zunyi, Guizhou, China,Jian Huang School of Laboratory Medicine, Affiliated Hospital of Zunyi Medical University, Zunyi,Guizhou, China
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Liang X, Pei TT, Li H, Zheng HY, Luo H, Cui Y, Tang MX, Zhao YJ, Xu P, Dong T. VgrG-dependent effectors and chaperones modulate the assembly of the type VI secretion system. PLoS Pathog 2021; 17:e1010116. [PMID: 34852023 PMCID: PMC8668125 DOI: 10.1371/journal.ppat.1010116] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 12/13/2021] [Accepted: 11/15/2021] [Indexed: 11/19/2022] Open
Abstract
The type VI secretion system (T6SS) is a spear-like nanomachine found in gram-negative pathogens for delivery of toxic effectors to neighboring bacterial and host cells. Its assembly requires a tip spike complex consisting of a VgrG-trimer, a PAAR protein, and the interacting effectors. However, how the spike controls T6SS assembly remains elusive. Here we investigated the role of three VgrG-effector pairs in Aeromonas dhakensis strain SSU, a clinical isolate with a constitutively active T6SS. By swapping VgrG tail sequences, we demonstrate that the C-terminal ~30 amino-acid tail dictates effector specificity. Double deletion of vgrG1&2 genes (VgrG3+) abolished T6SS secretion, which can be rescued by ectopically expressing chimeric VgrG3 with a VgrG1/2-tail but not the wild type VgrG3. In addition, deletion of effector-specific chaperones also severely impaired T6SS secretion, despite the presence of intact VgrG and effector proteins, in both SSU and Vibrio cholerae V52. We further show that SSU could deliver a V. cholerae effector VasX when expressing a plasmid-borne chimeric VgrG with VasX-specific VgrG tail and chaperone sequences. Pull-down analyses show that two SSU effectors, TseP and TseC, could interact with their cognate VgrGs, the baseplate protein TssK, and the key assembly chaperone TssA. Effectors TseL and VasX could interact with TssF, TssK and TssA in V. cholerae. Collectively, we demonstrate that chimeric VgrG-effector pairs could bypass the requirement of heterologous VgrG complex and propose that effector-stuffing inside the baseplate complex, facilitated by chaperones and the interaction with structural proteins, serves as a crucial structural determinant for T6SS assembly. Effectors of bacterial secretion systems are generally considered as secreted proteins for interspecies interactions rather than components of the secretion apparatus. Our results reveal the complex interactions of effectors, chaperones, and structural proteins are crucial for T6SS assembly, suggesting an integral role of effectors as parts of the apparatus and distinctive from other secretion systems.
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Affiliation(s)
- Xiaoye Liang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Tong-Tong Pei
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hao Li
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Hao-Yu Zheng
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Han Luo
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Yang Cui
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ming-Xuan Tang
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Ya-Jie Zhao
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
| | - Ping Xu
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Tao Dong
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
- Department of Immunology and Microbiology, School of Life Sciences, Southern University of Science and Technology, Shenzhen, China
- * E-mail:
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17
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Gallegos-Monterrosa R, Coulthurst SJ. The ecological impact of a bacterial weapon: microbial interactions and the Type VI secretion system. FEMS Microbiol Rev 2021; 45:fuab033. [PMID: 34156081 PMCID: PMC8632748 DOI: 10.1093/femsre/fuab033] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Accepted: 06/20/2021] [Indexed: 12/13/2022] Open
Abstract
Bacteria inhabit all known ecological niches and establish interactions with organisms from all kingdoms of life. These interactions are mediated by a wide variety of mechanisms and very often involve the secretion of diverse molecules from the bacterial cells. The Type VI secretion system (T6SS) is a bacterial protein secretion system that uses a bacteriophage-like machinery to secrete a diverse array of effectors, usually translocating them directly into neighbouring cells. These effectors display toxic activity in the recipient cell, making the T6SS an effective weapon during inter-bacterial competition and interactions with eukaryotic cells. Over the last two decades, microbiology research has experienced a shift towards using systems-based approaches to study the interactions between diverse organisms and their communities in an ecological context. Here, we focus on this aspect of the T6SS. We consider how our perspective of the T6SS has developed and examine what is currently known about the impact that bacteria deploying the T6SS can have in diverse environments, including niches associated with plants, insects and mammals. We consider how T6SS-mediated interactions can affect host organisms by shaping their microbiota, as well as the diverse interactions that can be established between different microorganisms through the deployment of this versatile secretion system.
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Affiliation(s)
| | - Sarah J Coulthurst
- School of Life Sciences, University of Dundee, Dow Street, Dundee DD1 5EH, UK
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Zhang A, Han Y, Huang Y, Hu X, Liu P, Liu X, Kan B, Liang W. vgrG is separately transcribed from hcp in T6SS orphan clusters and is under the regulation of IHF and HapR. Biochem Biophys Res Commun 2021; 559:15-20. [PMID: 33932896 DOI: 10.1016/j.bbrc.2021.04.092] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2021] [Accepted: 04/21/2021] [Indexed: 11/29/2022]
Abstract
V. cholerae, the causative agent of cholera epidemic, and V. fluvialis, the emerging foodborne pathogen, share highly homologous T6SS consisting of one large cluster and two small orphan or auxiliary clusters, and each of which was generally recognized as one operon. Here, we showed that the genes in each of the small clusters are organized into two transcriptional units. Specifically, the inner tube coding gene hcp/tssD is highly transcribed as one monocistron, while the tip component vgrG/tssI and its downstream effector and immunity genes are in one polycistron with very low transcriptional level. This conclusion is supported by qPCR analysis of mRNA abundance, reporter fusion analysis and transcriptional unit definition with RT-PCR analysis. Taking tssI2_a of V. fluvialis as an example, we further demonstrated that quorum sensing (QS) regulator HapR and global regulator IHF activate vgrG/tssI transcription by directly binding to its promoter region. Taken together, current studies deepen our understanding of T6SS system, highlighting its regulatory complexity during functional execution process.
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Affiliation(s)
- Anran Zhang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing, China
| | - Yu Han
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing, China
| | - Yuanming 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, Changbai Road 155, Changping District, Beijing, China
| | - Xiao Hu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing, China
| | - Ping Liu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing, China
| | - Xiaoshu Liu
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing, China
| | - Biao Kan
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing, China.
| | - Weili Liang
- State Key Laboratory of Infectious Disease Prevention and Control, National Institute for Communicable Disease Control and Prevention, Chinese Center for Disease Control and Prevention, Changbai Road 155, Changping District, Beijing, China.
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