A Phase-Variable Surface Layer from the Gut Symbiont Bacteroides thetaiotaomicron

Taketani, Mao; Donia, Mohamed S.; Jacobson, Amy N.; Lambris, John D.; Fischbach, Michael A.

doi:10.1128/mbio.01339-15

Cited by 18 publications

(17 citation statements)

References 38 publications

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“…5c ). Three of these repeats are identical to those that mediate recombination of the BT1927 promoter 30 and the remaining 4 only vary by a trinucleotide in the middle of each imperfect palindrome ( Fig. 5c ).…”

Section: Resultsmentioning

confidence: 98%

“…An additional 17 up-regulated genes belong to 8 loci that encode predicted outer membrane S-layer lipoproteins and OmpA β-barrel proteins. One of these (BT1927) was previously found to be phase-variable and increase B. thetaiotaomicron resistance to complement-mediated killing when locked in the “on” state 30 . The remaining S-layer clusters share both syntenic organization and weak homology to BT1927–25.…”

Section: Resultsmentioning

confidence: 99%

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Phase-variable capsular polysaccharides and lipoproteins modify bacteriophage susceptibility in Bacteroides thetaiotaomicron

et al. 2020

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A variety of cell surface structures dictate interactions between bacteria and their environment, including their viruses (bacteriophages). Members of the human gut Bacteroidetes characteristically produce several phase-variable capsular polysaccharides (CPS), but their contributions to bacteriophage interactions are unknown. To begin to understand how CPS impact Bacteroides -phage interactions, we isolated 71 B. thetaiotaomicron -infecting bacteriophages from two locations in the United States. Using B. thetaiotaomicron strains that express defined subsets of CPS, we show that CPS dictates host tropism for these phages and that expression of non-permissive CPS variants are selected under phage predation, enabling survival. In the absence of CPS, B. thetaiotaomicron escapes bacteriophage predation by altering expression of 8 distinct phase-variable lipoproteins. When constitutively expressed, one of these lipoproteins promotes resistance to multiple bacteriophages. Our results reveal important roles for Bacteroides CPS and other cell surface structures that allow these bacteria to persist under bacteriophage predation and hold important implications for using bacteriophages therapeutically to target gut symbionts.

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Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Phase-variable capsular polysaccharides and lipoproteins modify bacteriophage susceptibility in Bacteroides thetaiotaomicron

et al. 2020

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“…The modular nature of Type I specificity proteins allows the protein to change its recognition site by varying the N- and C-terminal TRD. Such domain shuffling and rearrangements of specificity-encoding genes has been demonstrated in numerous bacteria, and, in a few organisms, the shuffling is due to site-specific DNA inversions ( 11 , 16–19 ).…”

Section: Introductionmentioning

confidence: 99%

Analysis of a phase-variable restriction modification system of the human gut symbiont Bacteroides fragilis

Ben-Assa

Coyne

Fomenkov

et al. 2020

Nucleic Acids Research

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The genomes of gut Bacteroidales contain numerous invertible regions, many of which contain promoters that dictate phase-variable synthesis of surface molecules such as polysaccharides, fimbriae, and outer surface proteins. Here, we characterize a different type of phase-variable system of Bacteroides fragilis, a Type I restriction modification system (R-M). We show that reversible DNA inversions within this R-M locus leads to the generation of eight specificity proteins with distinct recognition sites. In vitro grown bacteria have a different proportion of specificity gene combinations at the expression locus than bacteria isolated from the mammalian gut. By creating mutants, each able to produce only one specificity protein from this region, we identified the R-M recognition sites of four of these S-proteins using SMRT sequencing. Transcriptome analysis revealed that the locked specificity mutants, whether grown in vitro or isolated from the mammalian gut, have distinct transcriptional profiles, likely creating different phenotypes, one of which was confirmed. Genomic analyses of diverse strains of Bacteroidetes from both host-associated and environmental sources reveal the ubiquity of phase-variable R-M systems in this phylum.

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“…In the haloarchaeon Haloquadratum walsbyi DSM 16790, two different genomic islands encode glycosyltransferases and S-layer glycoproteins [ 70 ]. Thus, viruses may exert an influence that is comparable to host immune system, producing not just different surface types, analogous to serotypes in bacterial pathogens but also a mechanism of switching the from one surface type to another as often seen in human pathogens and commensals [ 71 , 72 ].…”

Section: Discussionmentioning

confidence: 99%

Comparative Analysis of Surface Layer Glycoproteins and Genes Involved in Protein Glycosylation in the Genus Haloferax

Shalev

Soucy

Papke

et al. 2018

Genes

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Within the Haloferax genus, both the surface (S)-layer protein, and the glycans that can decorate it, vary between species, which can potentially result in many different surface types, analogous to bacterial serotypes. This variation may mediate phenotypes, such as sensitivity to different viruses and mating preferences. Here, we describe S-layer glycoproteins found in multiple Haloferax strains and perform comparative genomics analyses of major and alternative glycosylation clusters of isolates from two coastal sites. We analyze the phylogeny of individual glycosylation genes and demonstrate that while the major glycosylation cluster tends to be conserved among closely related strains, the alternative cluster is highly variable. Thus, geographically- and genetically-related strains may exhibit diverse surface structures to such an extent that no two isolates present an identical surface profile.

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A Phase-Variable Surface Layer from the Gut Symbiont Bacteroides thetaiotaomicron

Cited by 18 publications

References 38 publications

Phase-variable capsular polysaccharides and lipoproteins modify bacteriophage susceptibility in Bacteroides thetaiotaomicron

Phase-variable capsular polysaccharides and lipoproteins modify bacteriophage susceptibility in Bacteroides thetaiotaomicron

Analysis of a phase-variable restriction modification system of the human gut symbiont Bacteroides fragilis

Comparative Analysis of Surface Layer Glycoproteins and Genes Involved in Protein Glycosylation in the Genus Haloferax

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