Crosstalk between the ancestral type VII secretion system ESX-4 and other T7SS in Mycobacterium marinum

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.

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Sequence Analysis of Staphylococcus hyicus ATCC 11249T, an Etiological Agent of Exudative Epidermitis in Swine, Reveals a Type VII Secretion System Locus and a Novel 116-Kilobase Genomic Island Harboring Toxin-Encoding Genes

Genome Announcements ◽

10.1128/genomea.01525-14 ◽

2015 ◽

Vol 3 (1) ◽

Cited By ~ 5

Author(s):

Michael J. Calcutt ◽

Mark F. Foecking ◽

Hsin-Yeh Hsieh ◽

Pamela R. F. Adkins ◽

George C. Stewart ◽

...

Keyword(s):

Sequence Analysis ◽

Genomic Island ◽

Secretion System ◽

Etiological Agent ◽

Type Vii Secretion ◽

Type Vii Secretion System ◽

Encoding Genes

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A type VII secretion system of Streptococcus gallolyticus subsp. gallolyticus contributes to gut colonization and the development of colon tumors

PLoS Pathogens ◽

10.1371/journal.ppat.1009182 ◽

2021 ◽

Vol 17 (1) ◽

pp. e1009182

Author(s):

John Culver Taylor ◽

Xinsheng Gao ◽

Juan Xu ◽

Michael Holder ◽

Joseph Petrosino ◽

...

Keyword(s):

Bacterial Culture ◽

Secretion System ◽

Host Cells ◽

Secretion Systems ◽

Colon Tumors ◽

Type Vii Secretion ◽

Streptococcus Gallolyticus ◽

Gut Colonization ◽

Type Vii Secretion System

Streptococcus gallolyticus subspecies gallolyticus (Sgg) has a strong clinical association with colorectal cancer (CRC) and actively promotes the development of colon tumors. However, the molecular determinants involved in Sgg pathogenicity in the gut are unknown. Bacterial type VII secretion systems (T7SS) mediate pathogen interactions with their host and are important for virulence in pathogenic mycobacteria and Staphylococcus aureus. Through genome analysis, we identified a locus in Sgg strain TX20005 that encodes a putative type VII secretion system (designated as SggT7SST05). We showed that core genes within the SggT7SST05 locus are expressed in vitro and in the colon of mice. Western blot analysis showed that SggEsxA, a protein predicted to be a T7SS secretion substrate, is detected in the bacterial culture supernatant, indicating that this SggT7SST05 is functional. Deletion of SggT7SST05 (TX20005Δesx) resulted in impaired bacterial adherence to HT29 cells and abolished the ability of Sgg to stimulate HT29 cell proliferation. Analysis of bacterial culture supernatants suggest that SggT7SST05-secreted factors are responsible for the pro-proliferative activity of Sgg, whereas Sgg adherence to host cells requires both SggT7SST05-secreted and bacterial surface-associated factors. In a murine gut colonization model, TX20005Δesx showed significantly reduced colonization compared to the parent strain. Furthermore, in a mouse model of CRC, mice exposed to TX20005 had a significantly higher tumor burden compared to saline-treated mice, whereas those exposed to TX20005Δesx did not. Examination of the Sgg load in the colon in the CRC model suggests that SggT7SST05-mediated activities are directly involved in the promotion of colon tumors. Taken together, these results reveal SggT7SST05 as a previously unrecognized pathogenicity determinant for Sgg colonization of the colon and promotion of colon tumors.

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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

Microbiology Resource Announcements ◽

10.1128/mra.00962-19 ◽

2019 ◽

Vol 8 (45) ◽

Cited By ~ 2

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.

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