scholarly journals The Prophage and Plasmid Mobilome as a Likely Driver of Mycobacterium abscessus Diversity

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
Rebekah M. Dedrick ◽  
Haley G. Aull ◽  
Deborah Jacobs-Sera ◽  
Rebecca A. Garlena ◽  
Daniel A. Russell ◽  
...  
Keyword(s):  
Mycobacterium Abscessus ◽  
Genomic Variation ◽  
Host Cells ◽  
Clinical Isolates ◽  
Genetic Constitution ◽  
Secretion Systems ◽  
Emerging Pathogen ◽  
Content Type ◽  
Type Vii Secretion

ABSTRACT Mycobacterium abscessus is an emerging pathogen that is often refractory to antibiotic control. Treatment is further complicated by considerable variation among clinical isolates in both their genetic constitution and their clinical manifestations. Here, we show that the prophage and plasmid mobilome is a likely contributor to this variation. Prophages and plasmids are common, abundant, and highly diverse, and code for large repertoires of genes influencing virulence, antibiotic susceptibility, and defense against viral infection. At least 85% of the strains we describe carry one or more prophages, representing at least 17 distinct and diverse sequence “clusters,” integrated at 18 different attB locations. The prophages code for 19 distinct configurations of polymorphic toxin and toxin-immunity systems, each with WXG-100 motifs for export through type VII secretion systems. These are located adjacent to attachment junctions, are lysogenically expressed, and are implicated in promoting growth in infected host cells. Although the plethora of prophages and plasmids confounds the understanding of M. abscessus pathogenicity, they also provide an abundance of tools for M. abscessus engineering. IMPORTANCE Mycobacterium abscessus is an important emerging pathogen that is challenging to treat with current antibiotic regimens. There is substantial genomic variation in M. abscessus clinical isolates, but little is known about how this influences pathogenicity and in vivo growth. Much of the genomic variation is likely due to the large and varied mobilome, especially a large and diverse array of prophages and plasmids. The prophages are unrelated to previously characterized phages of mycobacteria and code for a diverse array of genes implicated in both viral defense and in vivo growth. Prophage-encoded polymorphic toxin proteins secreted via the type VII secretion system are common and highly varied and likely contribute to strain-specific pathogenesis.

scholarly journals Genome Sequence of Mycobacterium abscessus Phage phiT46-1

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Elizabeth D. Amarh ◽  
Rebekah M. Dedrick ◽  
Rebecca A. Garlena ◽  
Daniel A. Russell ◽  
Deborah Jacobs-Sera ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Mycobacterium Abscessus ◽  
Spontaneous Release ◽  
Secretion Systems ◽  
Content Type ◽  
Type Vii Secretion

ABSTRACT Mycobacteriophage phiT46-1 is a newly isolated Mycobacterium phage that was isolated by spontaneous release from Mycobacterium abscessus strain Taiwan-46 and infects M. abscessus strain BWH-C. Phage phiT46-1 is unrelated to previously described mycobacteriophages, has a 52,849-bp genome, and includes a polymorphic toxin-immunity cassette associated with type VII secretion systems.

scholarly journals Comparative Genomics ofesxGenes from Clinical Isolates of Mycobacterium tuberculosis Provides Evidence for Gene Conversion and Epitope Variation

2011 ◽  
Vol 79 (10) ◽  
pp. 4042-4049 ◽  
Author(s):  
Swapna Uplekar ◽  
Beate Heym ◽  
Véronique Friocourt ◽  
Jacques Rougemont ◽  
Stewart T. Cole
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Dna Sequences ◽  
Antigenic Variation ◽  
Clinical Isolates ◽  
Nucleotide Polymorphisms ◽  
Secretion Systems ◽  
Human Immune System ◽  
Single Nucleotide ◽  
Content Type ◽  
Type Vii Secretion

ABSTRACTThe 23-membered Esx protein family is involved in the host-pathogen interactions ofMycobacterium tuberculosis. These secreted proteins are among the most immunodominant antigens recognized by the human immune system and have thus been used to develop vaccines and immunodiagnostic tests for tuberculosis (TB). Gene pairs for 10 Esx proteins are contained in the ESX-1 to ESX-5 loci, encoding type VII secretion systems. A subset of Esx proteins can be further classified into the Mtb9.9, QILSS, and TB10.4 subfamilies. To survey genetic diversity in the Esx family and its potential for antigenic variation, we sequenced allesxgenes from 108 clinical isolates ofM. tuberculosisfrom different clades by using a targeted approach. A total of 109 unique single nucleotide polymorphisms (SNPs) were observed, and 59 of these were nonsynonymous. Some of the resultant amino acid substitutions affect known Esx epitopes, including two in the EsxB (CFP-10) and EsxH (TB10.4) antigens. Assessment of the SNP distribution across the Esx proteins revealed high genetic variability, especially in the Mtb9.9 and QILSS subfamilies, and more conservation in the ESX-1 to ESX-4 loci. Comparison of the DNA sequences of variableesxgenes provided clear evidence for recombination events between different genes in the same strain, some of which are predicted to truncate the corresponding protein. Many of these polymorphisms escape detection by ultrahigh-throughput sequencing using short sequence reads, as such approaches cannot distinguish between closely related genes. Theesxgene family is dynamic, and sequence changes likely lead to immune variation.

scholarly journals Genome Sequence of Mycobacterium abscessus Phage phiT45-1

2021 ◽  
Vol 10 (10) ◽  
Author(s):  
Elizabeth D. Amarh ◽  
Christian H. Gauthier ◽  
Rebekah M. Dedrick ◽  
Rebecca A. Garlena ◽  
Daniel A. Russell ◽  
...  
Keyword(s):  
Genome Sequence ◽  
Mycobacterium Smegmatis ◽  
Mycobacterium Abscessus ◽  
Secretion Systems ◽  
Content Type ◽  
Type Vii Secretion

ABSTRACT Mycobacteriophage phiT45-1 is a newly isolated bacteriophage spontaneously released from Mycobacterium abscessus strain Taiwan-45 that lytically infects M. abscessus strain BWH-C; phiT45-1 also infects M. abscessus ATCC 19977 but not Mycobacterium smegmatis. Phage phiT45-1 has a 43,407-bp genome and carries a polymorphic toxin-immunity cassette associated with type VII secretion systems.

scholarly journals BPSS1504, a Cluster 1 Type VI Secretion Gene, Is Involved in Intracellular Survival and Virulence of Burkholderia pseudomallei

2014 ◽  
Vol 82 (5) ◽  
pp. 2006-2015 ◽  
Author(s):  
Verena Hopf ◽  
André Göhler ◽  
Kristin Eske-Pogodda ◽  
Antje Bast ◽  
Ivo Steinmetz ◽  
...  
Keyword(s):  
Mutant Strain ◽  
Burkholderia Pseudomallei ◽  
Plaque Assay ◽  
Giant Cells ◽  
Host Cells ◽  
Wild Type ◽  
Secretion Systems ◽  
Content Type ◽  
Type Vi Secretion

ABSTRACTBurkholderia pseudomalleiis a Gram-negative rod and the causative agent of melioidosis, an emerging infectious disease of tropical and subtropical areas worldwide.B. pseudomalleiharbors a remarkable number of virulence factors, including six type VI secretion systems (T6SS). Using our previously described plaque assay screening system, we identified aB. pseudomalleitransposon mutant defective in theBPSS1504gene that showed reduced plaque formation. TheBPSS1504locus is encoded within T6SS cluster 1 (T6SS1), which is known to be involved in the pathogenesis ofB. pseudomalleiin mammalian hosts. For further analysis, aB. pseudomalleiBPSS1504deletion (BpΔBPSS1504) mutant and complemented mutant strain were constructed.B. pseudomalleilacking theBPSS1504gene was highly attenuated in BALB/c mice, whereas thein vivovirulence of the complemented mutant strain was fully restored to the wild-type level. TheBpΔBPSS1504mutant showed impaired intracellular replication and formation of multinucleated giant cells in macrophages compared with wild-type bacteria, whereas the induction of actin tail formation within host cells was not affected. These observations resembled the phenotype of a mutant lackinghcp1, which is an integral component of the T6SS1 apparatus and is associated with full functionality of the T6SS1. Transcriptional expression of the T6SS componentsvgrG,tssA, andhcp1, as well as the T6SS regulatorsvirAG,bprC, andbsaN, was not dependent onBPSS1504expression. However, secretion of Hcp1 was not detectable in the absence ofBPSS1504. Thus, BPSS1504 seems to serve as a T6SS component that affects Hcp1 secretion and is therefore involved in the integrity of the T6SS1 apparatus.

scholarly journals Regulation of Type VI Secretion System during Burkholderia pseudomallei Infection

2011 ◽  
Vol 79 (8) ◽  
pp. 3064-3073 ◽  
Author(s):  
Yahua Chen ◽  
Jocelyn Wong ◽  
Guang Wen Sun ◽  
Yichun Liu ◽  
Gek-Yen Gladys Tan ◽  
...  
Keyword(s):  
Burkholderia Pseudomallei ◽  
Host Cells ◽  
Virulence Determinants ◽  
Type Vi Secretion System ◽  
Secretion Systems ◽  
Content Type ◽  
Regulatory Cascade ◽  
Type Vi Secretion ◽  
Absolute Dependence

ABSTRACTType III and type VI secretion systems (T3SSs and T6SSs, respectively) are critical virulence determinants in several Gram-negative pathogens. InBurkholderia pseudomallei, the T3SS-3 and T6SS-1 clusters have been implicated in bacterial virulence in mammalian hosts. We recently discovered a regulatory cascade that coordinately controls the expression of T3SS-3 and T6SS-1. BsaN is a central regulator located within T3SS-3 for the expression of T3SS-3 effectors and regulators for T6SS-1 such as VirA-VirG (VirAG) and BprC. Whereas T6SS-1 gene expression was completely dependent on BprC when bacteria were grown in medium, the expression inside host cells was dependent on the two-component sensor-regulator VirAG, with the exception of thetssABoperon, which was dependent primarily on BprC. VirAG and BprC initiate different transcriptional start sites within T6SS-1, and VirAG is able to activate thehcp1promoter directly. We also provided novel evidence thatvirAG,bprC, andtssABare critical for T6SS-1 function in macrophages. Furthermore,virAGandbprCregulator mutants were avirulent in mice, demonstrating the absolute dependence of T6SS-1 expression on these regulatorsin vivo.

scholarly journals Type VII Secretion Substrates of Pathogenic Mycobacteria Are Processed by a Surface Protease

mBio ◽  
2019 ◽  
Vol 10 (5) ◽  
Author(s):  
Maroeska J. Burggraaf ◽  
Alexander Speer ◽  
Aniek S. Meijers ◽  
Roy Ummels ◽  
Astrid M. van der Sar ◽  
...  
Keyword(s):  
Cell Wall ◽  
Aspartic Protease ◽  
Mycobacterial Species ◽  
Secretion Systems ◽  
Aspartic Proteases ◽  
Content Type ◽  
Zebrafish Larvae ◽  
Type Vii Secretion ◽  
Unique Cell

ABSTRACT Tuberculosis, one of the world’s most severe infectious diseases, is caused by Mycobacterium tuberculosis. A major weapon of this pathogen is a unique cell wall that protects the pathogen from eradication by the immune system. Mycobacteria have specialized secretion systems, e.g., type VII secretion or ESX systems, to transport substrates across this cell wall. The largest group of proteins that are secreted by these ESX systems are the PE proteins. Previously, it was shown that the N-terminal PE domain of about 100 amino acids is required for secretion. Here, we describe the identification of an aspartic protease, designated PecA, that removes (part of) this PE domain at the cell surface. Nearly all of the observed PE_PGRS proteins are processed by PecA. Interestingly, the protease itself is also a secreted PE protein and subject to self-cleavage. Furthermore, a defect in surface processing has no effect on the activity of the PE lipase protein LipY but does seem to affect the functioning of other virulence factors, as a pecA mutant strain of Mycobacterium marinum shows moderate attenuation in zebrafish larvae. In conclusion, our results reveal the presence of a functional aspartic acid protease in M. marinum that cleaves LipY, itself as well as other members of the PE_PGRS family. Finally, mutants lacking PecA show growth attenuation in vivo, suggesting that PecA plays a role during infection. IMPORTANCE Aspartic proteases are common in eukaryotes and retroviruses but are relatively rare among bacteria (N. D. Rawlings and A. Bateman, BMC Genomics 10:437, 2009, https://doi.org/10.1186/1471-2164-10-437). In contrast to eukaryotic aspartic proteases, bacterial aspartic proteases are generally located in the cytoplasm. We have identified a surface-associated mycobacterial aspartic protease, PecA, which cleaves itself and many other type VII secretion substrates of the PE_PGRS family. PecA is present in most pathogenic mycobacterial species, including M. tuberculosis. In addition, pathogenicity of M. marinum is reduced in the ΔpecA mutant, indicating that PecA contributes to virulence.

scholarly journals Mycobacterium tuberculosis Toxin CpnT Is an ESX-5 Substrate and Requires Three Type VII Secretion Systems for Intracellular Secretion

mBio ◽  
2021 ◽  
Vol 12 (2) ◽  
Author(s):  
B. Izquierdo Lafuente ◽  
R. Ummels ◽  
C. Kuijl ◽  
W. Bitter ◽  
A. Speer
Keyword(s):  
Mycobacterium Tuberculosis ◽  
Host Cells ◽  
Secretion Systems ◽  
Macrophage Infection ◽  
Content Type ◽  
Secretion Pathway ◽  
Terminal Domain ◽  
Type Vii Secretion ◽  
Type Vii Secretion System ◽  
Axenic Conditions

ABSTRACT CpnT, a NAD+ glycohydrolase, is the only known toxin that is secreted by Mycobacterium tuberculosis. CpnT is composed of two domains; the C-terminal domain is the toxin, whereas the N-terminal domain is required for secretion. CpnT shows characteristics of type VII secretion (T7S) substrates, including a predicted helix-turn-helix domain followed by a secretion motif (YxxxE). Disruption of this motif indeed abolished CpnT secretion. By analyzing different mutants, we established that CpnT is specifically secreted by the ESX-5 system in Mycobacterium marinum under axenic conditions and during macrophage infection. Surprisingly, intracellular secretion of CpnT was also dependent on both ESX-1 and ESX-4. These secretion defects could be partially rescued by coinfection with wild-type bacteria, indicating that secreted effectors are involved in this process. In summary, our data reveal that three different type VII secretion systems have to be functional in order to observe intracellular secretion of the toxin CpnT. IMPORTANCE For decades, it was believed that the intracellular pathogen M. tuberculosis does not possess toxins. Only fairly recently it was discovered that CpnT is a potent secreted toxin of M. tuberculosis, causing necrotic cell death in host cells. However, until now the secretion pathway remained unknown. In our study, we were able to identify CpnT as a substrate of the mycobacterial type VII secretion system. Pathogenic mycobacteria have up to five different type VII secretion systems, called ESX-1 to ESX-5, which play distinct roles for the pathogen during growth or infection. We were able to elucidate that CpnT is exclusively secreted by the ESX-5 system in bacterial culture. However, to our surprise we discovered that, during infection studies, CpnT secretion relies on intact ESX-1, ESX-4, and ESX-5 systems. We elucidate for the first time the intertwined interplay of three different and independent secretion systems to secrete one substrate during infection.

Conserved and specialized functions of Type VII secretion systems in non-tuberculous mycobacteria

Microbiology ◽  
2021 ◽  
Vol 167 (7) ◽  
Author(s):  
Marion Lagune ◽  
Cecile Petit ◽  
Flor Vásquez Sotomayor ◽  
Matt D. Johansen ◽  
Kathrine S. H. Beckham ◽  
...  
Keyword(s):  
Type Species ◽  
Functional System ◽  
Mycobacterium Abscessus ◽  
Individual Species ◽  
Secretion Systems ◽  
Emerging Pathogens ◽  
Content Type ◽  
Link Type ◽  
Type Vii Secretion ◽  
Mycobacterium Xenopi

Non-tuberculous mycobacteria (NTM) are a large group of micro-organisms comprising more than 200 individual species. Most NTM are saprophytic organisms and are found mainly in terrestrial and aquatic environments. In recent years, NTM have been increasingly associated with infections in both immunocompetent and immunocompromised individuals, prompting significant efforts to understand the diverse pathogenic and signalling traits of these emerging pathogens. Since the discovery of Type VII secretion systems (T7SS), there have been significant developments regarding the role of these complex systems in mycobacteria. These specialised systems, also known as Early Antigenic Secretion (ESX) systems, are employed to secrete proteins across the inner membrane. They also play an essential role in virulence, nutrient uptake and conjugation. Our understanding of T7SS in mycobacteria has significantly benefited over the last few years, from the resolution of ESX-3 structure in Mycobacterium smegmatis , to ESX-5 structures in Mycobacterium xenopi and Mycobacterium tuberculosis . In addition, ESX-4, considered until recently as a non-functional system in both pathogenic and non-pathogenic mycobacteria, has been proposed to play an important role in the virulence of Mycobacterium abscessus ; an increasingly recognized opportunistic NTM causing severe lung diseases. These major findings have led to important new insights into the functional mechanisms of these biological systems, their implication in virulence, nutrient acquisitions and cell wall shaping, and will be discussed in this review.

scholarly journals hfqPlays Important Roles in Virulence and Stress Adaptation in Cronobacter sakazakii ATCC 29544

2015 ◽  
Vol 83 (5) ◽  
pp. 2089-2098 ◽  
Author(s):  
Seongok Kim ◽  
Hyelyeon Hwang ◽  
Kwang-Pyo Kim ◽  
Hyunjin Yoon ◽  
Dong-Hyun Kang ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Bacterial Species ◽  
Soft Agar ◽  
Host Cells ◽  
Neonatal Meningitis ◽  
Animal Cells ◽  
Content Type ◽  
Flagellar Biosynthesis

Cronobacterspp. are opportunistic pathogens that cause neonatal meningitis and sepsis with high mortality in neonates. Despite the peril associated withCronobacterinfection, the mechanisms of pathogenesis are still being unraveled. Hfq, which is known as an RNA chaperone, participates in the interaction with bacterial small RNAs (sRNAs) to regulate posttranscriptionally the expression of various genes. Recent studies have demonstrated that Hfq contributes to the pathogenesis of numerous species of bacteria, and its roles are varied between bacterial species. Here, we tried to elucidate the role of Hfq inC. sakazakiivirulence. In the absence ofhfq,C. sakazakiiwas highly attenuated in disseminationin vivo, showed defects in invasion (3-fold) into animal cells and survival (103-fold) within host cells, and exhibited low resistance to hydrogen peroxide (102-fold). Remarkably, the loss ofhfqled to hypermotility on soft agar, which is contrary to what has been observed in other pathogenic bacteria. The hyperflagellated bacteria were likely to be attributable to the increased transcription of genes associated with flagellar biosynthesis in a strain lackinghfq. Together, these data strongly suggest thathfqplays important roles in the virulence ofC. sakazakiiby participating in the regulation of multiple genes.

scholarly journals Neurotrophin Receptor TrkC Is an Entry Receptor for Trypanosoma cruzi in Neural, Glial, and Epithelial Cells

2011 ◽  
Vol 79 (10) ◽  
pp. 4081-4087 ◽  
Author(s):  
Craig Weinkauf ◽  
Ryan Salvador ◽  
Mercio PereiraPerrin
Keyword(s):  
Trypanosoma Cruzi ◽  
Chagas Disease ◽  
Mammalian Cells ◽  
Chinese Hamster ◽  
Neuronal Cell ◽  
Host Cells ◽  
Neurotrophin Receptor ◽  
Content Type

ABSTRACTTrypanosoma cruzi, the agent of Chagas' disease, infects a variety of mammalian cells in a process that includes multiple cycles of intracellular division and differentiation starting with host receptor recognition by a parasite ligand(s). Earlier work in our laboratory showed that the neurotrophin-3 (NT-3) receptor TrkC is activated byT. cruzisurfacetrans-sialidase, also known as parasite-derived neurotrophic factor (PDNF). However, it has remained unclear whether TrkC is used byT. cruzito enter host cells. Here, we show that a neuronal cell line (PC12-NNR5) relatively resistant toT. cruzibecame highly susceptible to infection when overexpressing human TrkC but not human TrkB. Furthermore,trkCtransfection conferred an ∼3.0-fold intracellular growth advantage. Sialylation-deficient Chinese hamster ovarian (CHO) epithelial cell lines Lec1 and Lec2 also became much more permissive toT. cruziafter transfection with thetrkCgene. Additionally, NT-3 specifically blockedT. cruziinfection of the TrkC-NNR5 transfectants and of naturally permissive TrkC-bearing Schwann cells and astrocytes, as did recombinant PDNF. Two specific inhibitors of Trk autophosphorylation (K252a and AG879) and inhibitors of Trk-induced MAPK/Erk (U0126) and Akt kinase (LY294002) signaling, but not an inhibitor of insulin-like growth factor 1 receptor, abrogated TrkC-mediated cell invasion. Antibody to TrkC blockedT. cruziinfection of the TrkC-NNR5 transfectants and of cells that naturally express TrkC. The TrkC antibody also significantly and specifically reduced cutaneous infection in a mouse model of acute Chagas' disease. TrkC is ubiquitously expressed in the peripheral and central nervous systems, and in nonneural cells infected byT. cruzi, including cardiac and gastrointestinal muscle cells. Thus, TrkC is implicated as a functional PDNF receptor in cell entry, independently of sialic acid recognition, mediating broadT. cruziinfection bothin vitroandin vivo.

Sign in / Sign up

Export Citation Format

Share Document