scholarly journals ESX-1-Independent Horizontal Gene Transfer by Mycobacterium tuberculosis Complex Strains

mBio ◽  
2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Jan Madacki ◽  
Mickael Orgeur ◽  
Guillem Mas Fiol ◽  
Wafa Frigui ◽  
Laurence Ma ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Mycobacterium Smegmatis ◽  
Secretion System ◽  
Dna Transfer ◽  
Chromosomal Dna ◽  
Content Type ◽  
Type Vii Secretion ◽  
Wide Range ◽  
Population Structures ◽  
Type Vii Secretion System

ABSTRACT Current models of horizontal gene transfer (HGT) in mycobacteria are based on “distributive conjugal transfer” (DCT), an HGT type described in the fast-growing, saprophytic model organism Mycobacterium smegmatis, which creates genome mosaicism in resulting strains and depends on an ESX-1 type VII secretion system. In contrast, only few data on interstrain DNA transfer are available for tuberculosis-causing mycobacteria, for which chromosomal DNA transfer between two Mycobacterium canettii strains was reported, a process which, however, was not observed for Mycobacterium tuberculosis strains. Here, we have studied a wide range of human- and animal-adapted members of the Mycobacterium tuberculosis complex (MTBC) using an optimized filter-based mating assay together with three selected strains of M. canettii that acted as DNA recipients. Unlike in previous approaches, we obtained a high yield of thousands of recombinants containing transferred chromosomal DNA fragments from various MTBC donor strains, as confirmed by whole-genome sequence analysis of 38 randomly selected clones. While the genome organizations of the obtained recombinants showed mosaicisms of donor DNA fragments randomly integrated into a recipient genome backbone, reminiscent of those described as being the result of ESX-1-mediated DCT in M. smegmatis, we observed similar transfer efficiencies when ESX-1-deficient donor and/or recipient mutants were used, arguing that in tubercle bacilli, HGT is an ESX-1-independent process. These findings provide new insights into the genetic events driving the pathoevolution of M. tuberculosis and radically change our perception of HGT in mycobacteria, particularly for those species that show recombinogenic population structures despite the natural absence of ESX-1 secretion systems. IMPORTANCE Data on the bacterial sex-mediated impact on mycobacterial evolution are limited. Hence, our results presented here are of importance as they clearly demonstrate the capacity of a wide range of human- and animal-adapted Mycobacterium tuberculosis complex (MTBC) strains to transfer chromosomal DNA to selected strains of Mycobacterium canettii. Most interestingly, we found that interstrain DNA transfer among tubercle bacilli was not dependent on a functional ESX-1 type VII secretion system, as ESX-1 deletion mutants of potential donor and/or recipient strains yielded numbers of recombinants similar to those of their respective parental strains. These results argue that HGT in tubercle bacilli is organized in a way different from that of the most widely studied Mycobacterium smegmatis model, a finding that is also relevant beyond tubercle bacilli, given that many mycobacteria, like, for example, Mycobacterium avium or Mycobacterium abscessus, are naturally devoid of an ESX-1 secretion system but show recombinogenic, mosaic-like genomic population structures.

scholarly journals A Duplicated ESAT-6 Region of ESX-5 Is Involved in Protein Export and Virulence of Mycobacteria

2015 ◽  
Vol 83 (11) ◽  
pp. 4349-4361 ◽  
Author(s):  
Swati Shah ◽  
Joe R. Cannon ◽  
Catherine Fenselau ◽  
Volker Briken
Keyword(s):  
Secretion System ◽  
Bacterial Virulence ◽  
Inflammasome Activation ◽  
Zebrafish Model ◽  
Content Type ◽  
Type Vii Secretion ◽  
Specific Subset ◽  
Host Cell Death ◽  
Type Vii Secretion System

ABSTRACTThe ESX-5 secretion system ofMycobacterium tuberculosisis important for bacterial virulence and for the secretion of the large PE/PPE protein family, whose genes constitute 10% of theM. tuberculosisgenome. A four-gene region of the ESX-5 system is duplicated three times in theM. tuberculosisgenome, but the functions of these duplicates are unknown. Here we investigated one of these duplicates: the region carrying theesxI,esxJ,ppe15, andpe8genes (ESX-5a). An ESX-5a deletion mutant in the model systemM. marinumbackground was deficient in the secretion of some members of the PE/PPE family of proteins. Surprisingly, we also identified other proteins that are not members of this family, thus expanding the range of ESX-5 secretion substrates. In addition, we demonstrated that ESX-5a is important for the virulence ofM. marinumin the zebrafish model. Furthermore, we showed the role of theM. tuberculosisESX-5a region in inflammasome activation but not host cell death induction, which is different from the case for theM. tuberculosisESX-5 system. In conclusion, the ESX-5a region is nonredundant with its ESX-5 paralog and is necessary for secretion of a specific subset of proteins inM. tuberculosisandM. marinumthat are important for bacterial virulence ofM. marinum. Our findings point to a role for the three ESX-5 duplicate regions in the selection of substrates for secretion via ESX-5, and hence, they provide the basis for a refined model of the molecular mechanism of this type VII secretion system.

scholarly journals The Whole-Genome Sequence of Plasmid-Bearing Staphylococcus argenteus Strain B3-25B from Retail Beef Liver Encodes the Type VII Secretion System and Several Virulence Factors

2019 ◽  
Vol 8 (45) ◽  
Author(s):  
Leena Neyaz ◽  
Anand B. Karki ◽  
Mohamed K. Fakhr
Keyword(s):  
Virulence Factors ◽  
Genome Sequence ◽  
Secretion System ◽  
Whole Genome Sequence ◽  
Whole Genome ◽  
Circular Chromosome ◽  
Beef Liver ◽  
Content Type ◽  
Type Vii Secretion ◽  
Type Vii Secretion System

The whole-genome sequence of Staphylococcus argenteus strain B3-25B, isolated from retail beef liver, comprises a circular chromosome (2,676,222 bp) and a single plasmid (21,570 bp). The chromosome harbors genes encoding the type VII secretion system and several virulence factors.

scholarly journals CFP-10 from Mycobacterium tuberculosis Selectively Activates Human Neutrophils through a Pertussis Toxin-Sensitive Chemotactic Receptor

2014 ◽  
Vol 83 (1) ◽  
pp. 205-213 ◽  
Author(s):  
Amanda Welin ◽  
Halla Björnsdottir ◽  
Malene Winther ◽  
Karin Christenson ◽  
Tudor Oprea ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Pertussis Toxin ◽  
Human Neutrophils ◽  
Content Type ◽  
Chaperone Function ◽  
Type Vii Secretion ◽  
Chaperone Protein ◽  
Type Vii Secretion System ◽  
G Protein Coupled

Upon infection withMycobacterium tuberculosis, neutrophils are massively recruited to the lungs, but the role of these cells in combating the infection is poorly understood. Through a type VII secretion system,M. tuberculosisreleases a heterodimeric protein complex, containing a 6-kDa early secreted antigenic target (ESAT-6) and a 10-kDa culture filtrate protein (CFP-10), that is essential for virulence. Whereas the ESAT-6 component possesses multiple virulence-related activities, no direct biological activity of CFP-10 has been shown, and CFP-10 has been described as a chaperone protein for ESAT-6. We here show that the ESAT-6:CFP-10 complex induces a transient release of Ca2+from intracellular stores in human neutrophils. Surprisingly, CFP-10 rather than ESAT-6 was responsible for triggering the Ca2+response, in a pertussis toxin-sensitive manner, suggesting the involvement of a G-protein-coupled receptor. In line with this, the response was accompanied by neutrophil chemotaxis and activation of the superoxide-producing NADPH-oxidase. Neutrophils were unique among leukocytes in responding to CFP-10, as monocytes and lymphocytes failed to produce a Ca2+signal upon stimulation with theM. tuberculosisprotein. Hence, CFP-10 may contribute specifically to neutrophil recruitment and activation duringM. tuberculosisinfection, representing a novel biological role for CFP-10 in the ESAT-6:CFP-10 complex, beyond the previously described chaperone function.

scholarly journals Rerouting of an Esx substrate pair from the ESX-1 type VII secretion system to ESX-5 by modifying a PE/PPE substrate pair

2020 ◽  
Author(s):  
Merel P.M. Damen ◽  
Trang H. Phan ◽  
Roy Ummels ◽  
Alba Rubio-Canalejas ◽  
Wilbert Bitter ◽  
...  
Keyword(s):  
Secretion System ◽  
Extracellular Proteins ◽  
Secretion Systems ◽  
Secretion Pathway ◽  
Type Vii Secretion ◽  
Wide Range ◽  
Type Vii Secretion System ◽  
Chaperone Binding ◽  
Determining Factor ◽  
Determinant Factor

AbstractType VII secretion systems (T7SSs) secrete a wide range of extracellular proteins that play important roles in bacterial viability and in host-pathogen interactions of pathogenic mycobacteria. There are five subtypes of mycobacterial T7SSs, called ESX-1 to ESX-5, and four classes of T7SS substrates, namely the Esx, PE, PPE and Esp proteins. At least some of these substrates are secreted as heterodimers. The ESX systems mediate the secretion of specific members of the Esx, PE and PPE proteins, raising the question how these substrates are recognized in a system-specific fashion. PE/PPE heterodimers interact with their cognate EspG chaperones, which recently has been shown to determine their designated secretion pathway. Both structural and pulldown analysis suggest that EspG is unable to interact with Esx proteins and therefore the determining factor for system-specificity of these substrates remains unknown. In this study, we have investigated the secretion specificity of the ESX-1 substrate pair EsxB_1/EsxA_1 (MMAR_0187/MMAR _0188) in Mycobacterium marinum. While this substrate pair was hardly secreted when ectopically expressed, secretion was observed when EsxB_1/EsxA_1 was co-expressed together with PE35/PPE68_1 (MMAR_0185/MMAR_0186), which are encoded by the same operon. Surprisingly, co-expressing EsxB_1/EsxA_1 with a modified PE35/PPE68_1 version that carried the EspG5 chaperone binding domain, previously shown to redirect this substrate pair to the ESX-5 system, also resulted in co-secretion of EsxB_1/EsxA_1 via ESX-5. Our data suggest a secretion model in which PE35/PPE68_1 is a determinant factor for the system-specific secretion of EsxB_1/EsxA_1.

scholarly journals A heterodimer of EsxA and EsxB is involved in sporulation and is secreted by a type VII secretion system in Streptomyces coelicolor

Microbiology ◽  
2010 ◽  
Vol 156 (6) ◽  
pp. 1719-1729 ◽  
Author(s):  
Sandra Akpe San Roman ◽  
Paul D. Facey ◽  
Lorena Fernandez-Martinez ◽  
Caridad Rodriguez ◽  
Carlos Vallin ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Streptomyces Coelicolor ◽  
Regulatory Gene ◽  
Secretion System ◽  
Model Species ◽  
Type Vii Secretion ◽  
Expression Of Genes ◽  
Dna Contents ◽  
Aerial Hyphae ◽  
Type Vii Secretion System

An esx locus, related to the multiple esx loci of Mycobacterium tuberculosis, is conserved in all sequenced Streptomyces genomes, where it is associated with the developmental regulatory gene bldB. Here we demonstrate that the esxBA operon, comprising part of the locus, has a novel morphogenetic function in the model species Streptomyces coelicolor. This operon encodes two proteins belonging to the WXG-100 superfamily that can form a heterodimer and are secreted in the absence of signal sequences. A mutation in esxBA results in a delay in sporulation, with eventual development of aerial hyphae with chains of abnormally sized spore compartments possessing irregular DNA contents. During early sporulation, expression of the operon is elevated in a bldB mutant. Other genes in the locus, notably SCO5734 and SCO5721, encode components of a type VII secretion system. Disruption of either of these genes prevents secretion of EsxAB but has no effect on sporulation. To explain the morphogenetic function of EsxAB, we propose that the heterodimer sequesters a regulator of expression of genes involved in nucleoid organization during sporulation.

scholarly journals Mycobacterium tuberculosis cording in the cytosol of live lymphatic endothelial cells

2019 ◽  
Author(s):  
Thomas R. Lerner ◽  
Christophe J. Queval ◽  
Rachel P. Lai ◽  
Matthew Russell ◽  
Antony Fearns ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Mycobacterium Tuberculosis ◽  
Secretion System ◽  
Lymphatic Endothelial Cells ◽  
Rna Seq ◽  
Size Dependent ◽  
Type Vii Secretion ◽  
Type Vii Secretion System ◽  
Dependent Mechanism

AbstractThe ability of Mycobacterium tuberculosis to form serpentine cords is intrinsically related to its virulence, but specifically how M. tuberculosis cording contributes to pathogenesis remains obscure. We show that several M. tuberculosis clinical isolates form intracellular cords in primary human lymphatic endothelial cells (hLEC) in vitro and also in the lymph nodes of patients with tuberculosis. We identified via RNA-seq a transcriptional programme in hLEC that activates cellular pro-survival and cytosolic surveillance of intracellular pathogens pathways. Consistent with this, cytosolic access of hLEC is required for intracellular M. tuberculosis cording; and cord formation is dependent on the M. tuberculosis ESX-1 type VII secretion system and the mycobacterial lipid PDIM. Finally, we show that M. tuberculosis cording is a novel size-dependent mechanism used by the pathogen to evade xenophagy in the cytosol of endothelial cells. These results provide a mechanism that explains the long-standing association between M. tuberculosis cording and virulence.

scholarly journals Crystallographic observation of the movement of the membrane-distal domain of the T7SS core component EccB1 fromMycobacterium tuberculosis

2016 ◽  
Vol 72 (2) ◽  
pp. 139-144
Author(s):  
Xiao-Qian Xie ◽  
Xiao-Li Zhang ◽  
Chao Qi ◽  
De-Feng Li ◽  
Joy Fleming ◽  
...  
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Atpase Activity ◽  
Virulence Factors ◽  
Conformational Changes ◽  
Secretion System ◽  
Secretion Systems ◽  
Core Component ◽  
Substrate Transport ◽  
Type Vii Secretion ◽  
Type Vii Secretion System

The protein EccB1, a core component of the type VII secretion system (T7SS) ofMycobacterium tuberculosis, has been identified as an ATPase and is essential for the secretion of virulence factors by the ESX-1 system. In a previous study, EccB1 structures were determined in two different conformations. Here, two new conformations are identified and described. These four conformations present snapshots of the swinging movement of the membrane-distal domain A2. The movement of this domain involves conformational changes in two flexible loops (loop A, residues 243–264, and loop B, residues 324–341) which are rich in proline and glycine residues and connect domain A2 to domains C1 and B2. It is proposed that the movement of this domain is related to the ATPase activity of EccB1 and its homologues, as well as to the substrate transport of ESX secretion systems.

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