scholarly journals An Escherichia coli Effector Protein Promotes Host Mutation via Depletion of DNA Mismatch Repair Proteins

mBio ◽  
2013 ◽  
Vol 4 (3) ◽  
Author(s):  
Oliver David Kenneth Maddocks ◽  
Karen Mary Scanlon ◽  
Michael S. Donnenberg
Keyword(s):  
Escherichia Coli ◽  
Host Cell ◽  
Mismatch Repair ◽  
Colorectal Carcinogenesis ◽  
Effector Protein ◽  
Repair System ◽  
Content Type ◽  
E Coli ◽  
Dna Mismatch ◽  
Mmr Proteins

ABSTRACT Enteropathogenic Escherichia coli (EPEC) is an attaching and effacing (A/E) human pathogen that causes diarrhea during acute infection, and it can also sustain asymptomatic colonization. A/E E. coli depletes host cell DNA mismatch repair (MMR) proteins in colonic cell lines and has been detected in colorectal cancer (CRC) patients. However, until now, a direct link between infection and host mutagenesis has not been fully demonstrated. Here we show that the EPEC-secreted effector protein EspF is critical for complete EPEC-induced depletion of MMR proteins. The mechanism of EspF activity on MMR protein was posttranscriptional and dependent on EspF mitochondrial targeting. EPEC infection also induced EspF-independent elevation of host reactive oxygen species levels. Moreover, EPEC infection significantly increased spontaneous mutation frequency in host cells, and this effect was dependent on mitochondrially targeted EspF. Taken together, these results support the hypothesis that A/E E. coli can promote colorectal carcinogenesis in humans. IMPORTANCE There is mounting evidence linking the gut microbiota with the induction of colorectal tumorigenesis. We previously described the downregulation of host cell mismatch repair (MMR) protein levels upon enteropathogenic Escherichia coli (EPEC) infection and speculated that this depletion may lead to an ablated DNA repair system. In this work, we identify EspF, a translocated EPEC effector protein, as one of the factors required for this phenotype and show that this effector protein must be targeted to the mitochondria in order to exert its effect. Furthermore, we found that the impaired mismatch repair system resulting from EPEC infection led to the generation of spontaneous mutations within host DNA at a site of microsatellite instability, a trait typical of colorectal tumors. Thus, this work provides a novel means by which enteric bacteria may promote colorectal carcinogenesis.

Interactions between microsatellite instability and human gut colonization by Escherichia coli in colorectal cancer

2017 ◽  
Vol 131 (6) ◽  
pp. 471-485 ◽  
Author(s):  
Johan Gagnière ◽  
Virginie Bonnin ◽  
Anne-Sophie Jarrousse ◽  
Emilie Cardamone ◽  
Allison Agus ◽  
...  
Keyword(s):  
Colorectal Cancer ◽  
Escherichia Coli ◽  
Microsatellite Instability ◽  
Colorectal Carcinogenesis ◽  
E Coli ◽  
Dna Mismatch ◽  
Gut Colonization ◽  
Pathogenic Escherichia Coli ◽  
Mmr Proteins

Recent studies suggest that colonization of colonic mucosa by pathogenic Escherichia coli could be involved in the development of colorectal cancer (CRC), especially through the production of genotoxins such as colibactin and/or by interfering with the DNA mismatch repair (MMR) pathway that leads to microsatellite instability (MSI). The present study, performed on 88 CRC patients, revealed a significant increase in E. coli colonization in the MSI CRC phenotype. In the same way, E. coli persistence and internalization were increased in vitro in MMR-deficient cells. Moreover, we demonstrated that colibactin-producing E. coli induce inhibition of the mutL homologue 1 (MLH1) MMR proteins, which could lead to genomic instability. However, colibactin-producing E. coli were more frequently identified in microsatellite stable (MSS) CRC. The present study suggests differences in the involvement of colibactin-producing E. coli in colorectal carcinogenesis according to the CRC phenotype. Further host–pathogen interactions studies should take into account CRC phenotypes.

scholarly journals Saturation of DNA Mismatch Repair and Error Catastrophe by a Base Analogue in Escherichia coli

Genetics ◽  
2002 ◽  
Vol 161 (4) ◽  
pp. 1363-1371
Author(s):  
Kazuo Negishi ◽  
David Loakes ◽  
Roel M Schaaper
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Dna Mismatch Repair ◽  
Repair System ◽  
Mutagenic Action ◽  
Wild Type ◽  
Dna Mismatch ◽  
Cell Counts ◽  
Error Catastrophe ◽  
Mismatch Repair System

Abstract Deoxyribosyl-dihydropyrimido[4,5-c][1,2]oxazin-7-one (dP) is a potent mutagenic deoxycytidine-derived base analogue capable of pairing with both A and G, thereby causing G · C → A · T and A · T → G · C transition mutations. We have found that the Escherichia coli DNA mismatch-repair system can protect cells against this mutagenic action. At a low dose, dP is much more mutagenic in mismatch-repair-defective mutH, mutL, and mutS strains than in a wild-type strain. At higher doses, the difference between the wild-type and the mutator strains becomes small, indicative of saturation of mismatch repair. Introduction of a plasmid containing the E. coli mutL+ gene significantly reduces dP-induced mutagenesis. Together, the results indicate that the mismatch-repair system can remove dP-induced replication errors, but that its capacity to remove dP-containing mismatches can readily be saturated. When cells are cultured at high dP concentration, mutant frequencies reach exceptionally high levels and viable cell counts are reduced. The observations are consistent with a hypothesis in which dP-induced cell killing and growth impairment result from excess mutations (error catastrophe), as previously observed spontaneously in proofreading-deficient mutD (dnaQ) strains.

scholarly journals Structure of recombinants from conjugational crosses between Escherichia coli donor and mismatch-repair deficient Salmonella typhimurium recipients.

Genetics ◽  
1994 ◽  
Vol 136 (1) ◽  
pp. 17-26
Author(s):  
I Matic ◽  
M Radman ◽  
C Rayssiguier
Keyword(s):  
Escherichia Coli ◽  
Salmonella Typhimurium ◽  
Mismatch Repair ◽  
Genomic Dna ◽  
Sequence Divergence ◽  
Physical Analysis ◽  
Repair System ◽  
Donor Genome ◽  
E Coli ◽  
Recombination Pathway

Abstract To get more insight into the control of homologous recombination between diverged DNA by the Mut proteins of the long-patch mismatch repair system, we have studied interspecies Escherichia coli/Salmonella typhimurium recombination. Knowing that the same recombination pathway (RecABCD) is responsible for intraspecies and interspecies recombination, we have now studied the structure (replacement vs. addition-type or other rearrangement-type recombinants) of 81 interspecies recombinants obtained in conjugational crosses between E. coli donor and mutL, mutS, mutH, mutU or mut+ S. typhimurium recipients. Taking advantage of high interspecies sequence divergence, a physical analysis was performed on one third of the E. coli Hfr genome, which was expected to be transferred to S. typhimurium F- recipients during 40 min before interruption of the mating. Probes specific for each species were hybridized on dot blots of genomic DNA, or on colonies, and the composition of the rrn operons was determined from purified genomic DNA. With very few exceptions, the structure of these interspecies recombinants corresponds to replacements of one continuous block of the recipient genome by the corresponding region of the donor genome.

scholarly journals Conversion of Commensal Escherichia coli K-12 to an Invasive Form via Expression of a Mutant Histone-Like Protein

mBio ◽  
2011 ◽  
Vol 2 (5) ◽  
Author(s):  
Preeti Koli ◽  
Sudhanshu Sudan ◽  
David Fitzgerald ◽  
Sankar Adhya ◽  
Sudeshna Kar
Keyword(s):  
Escherichia Coli ◽  
Host Cell ◽  
Cell Apoptosis ◽  
Transcription Profile ◽  
Intracellular Replication ◽  
Content Type ◽  
E Coli ◽  
Host Cell Apoptosis ◽  
K 12 ◽  
Cellular Transcription

ABSTRACTThe HUαE38K, V42Lmutant of the bacterial histone-like protein HU causes a major change in the transcription profile of the commensal organismEscherichia coliK-12 (Kar S, Edgar R, Adhya S, Proc. Natl. Acad. Sci. U. S. A. 102:16397–16402, 2005). Among the upregulated genes are several related to pathogenic interactions with mammalian cells, as evidenced by the expression of curli fibers, Ivy, and hemolysin E. WhenE. coliK-12/ HUαE38K, V42Lwas added to Int-407 cells, there was host cell invasion, phagosomal disruption, and intracellular replication. The invasive trait was also retained in a murine ileal loop model and intestinal explant assays. In addition to invasion, the internalized bacteria caused a novel subversion of host cell apoptosis through modification and regulation of the BH3-only proteins BimELand Puma. Changes in the transcription profile were attributed to positive supercoiling of DNA leading to the altered availability of relevant promoters. Using theE. coliK-12/HUαE38K, V42Lvariant as a model, we propose that traditional commensalE. colican adopt an invasive lifestyle through reprogramming its cellular transcription, without gross genetic changes.IMPORTANCEEscherichia coliK-12 is well established as a benign laboratory strain and a human intestinal commensal. Recent evidences, however, indicate that the typical noninvasive nature of residentE. colican be reversed under specific circumstances even in the absence of any major genomic flux. We previously engineered anE. colistrain with a mutant histone-like protein, HU, which exhibited significant changes in nucleoid organization and global transcription. Here we showed that the changes induced by the mutant HU have critical functional consequences: from a strict extracellular existence, the mutantE. coliadopts an almost obligate intracellular lifestyle. The internalizedE. coliexhibits many of the prototypical characteristics of traditional intracellular bacteria, like phagosomal escape, intracellular replication, and subversion of host cell apoptosis. We suggest thatE. coliK-12 can switch between widely divergent lifestyles in relation to mammalian host cells by reprogramming its cellular transcription program and without gross changes in its genomic content.

scholarly journals Is Thymidine Glycol Containing DNA a Substrate of E. coli DNA Mismatch Repair System?

PLoS ONE ◽  
2014 ◽  
Vol 9 (8) ◽  
pp. e104963 ◽  
Author(s):  
Svetlana A. Perevozchikova ◽  
Roman M. Trikin ◽  
Roger J. Heinze ◽  
Elena A. Romanova ◽  
Tatiana S. Oretskaya ◽  
...  
Keyword(s):  
Mismatch Repair ◽  
Dna Mismatch Repair ◽  
Repair System ◽  
E Coli ◽  
Dna Mismatch ◽  
Dna Mismatch Repair System ◽  
Mismatch Repair System ◽  
Thymidine Glycol

scholarly journals Spontaneous Mutations Occur Near Dam Recognition Sites in a dam  -  Escherichia coli Host

Genetics ◽  
1987 ◽  
Vol 116 (3) ◽  
pp. 343-347
Author(s):  
Margaretha Carraway ◽  
Philip Youderian ◽  
M G Marinus
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Spontaneous Mutation ◽  
Repair System ◽  
Base Pairs ◽  
Dna Mismatch ◽  
Recognition Sites ◽  
Mismatch Repair System ◽  
Phage P22

ABSTRACT The mismatch repair system of Escherichia coli K12 removes mispaired bases from DNA. Mismatch repair can occur on either strand of DNA if it lacks N6-methyladenines within 5′-GATC-3′ sequences. In hemimethylated heteroduplexes, repair occurs preferentially on the unmethylated strand. If both strands are fully methylated, repair is inhibited. Mutant (dam  -) strains of E. coli defective in the adenine methylase that recognizes 5′-GATC-3′ sequences (Dam), and therefore defective in mismatch repair, show increased spontaneous mutation rates compared to otherwise isogenic dam  + hosts. We have isolated and characterized 91 independent mutations that arise as a consequence of the Dam- defect in a plasmid-borne phage P22 repressor gene, mnt. The majority of these mutations are A:T→G:C transitions that occur within six base pairs of the two 5′-GATC-3′ sequences in the mnt gene. In contrast, the spectrum of mnt  - mutations in a dam  + host is comprised of a majority of insertions of IS elements and deletions that do not cluster near Dam recognition sites. These results show that Dam-directed post-replicative mismatch repair plays a significant role in the rectification of potential transition mutations in vivo, and suggest that sequences associated with Dam recognition sites are particularly prone to replication or repair errors.

scholarly journals The Adherent/Invasive Escherichia coli Strain LF82 Invades and Persists in Human Prostate Cell Line RWPE-1, Activating a Strong Inflammatory Response

2016 ◽  
Vol 84 (11) ◽  
pp. 3105-3113 ◽  
Author(s):  
Maria P. Conte ◽  
Marta Aleandri ◽  
Massimiliano Marazzato ◽  
Antonietta L. Conte ◽  
Cecilia Ambrosi ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Inflammatory Response ◽  
Host Cell ◽  
Cell Line ◽  
Neonatal Meningitis ◽  
Prostate Cell ◽  
Content Type ◽  
E Coli ◽  
Prostate Cell Line ◽  
Strong Inflammatory Response

Adherent/invasiveEscherichia coli(AIEC) strains have recently been receiving increased attention because they are more prevalent and persistent in the intestine of Crohn's disease (CD) patients than in healthy subjects. Since AIEC strains show a high percentage of similarity to extraintestinal pathogenicE. coli(ExPEC), neonatal meningitis-associatedE. coli(NMEC), and uropathogenicE. coli(UPEC) strains, here we compared AIEC strain LF82 with a UPEC isolate (strain EC73) to assess whether LF82 would be able to infect prostate cells as an extraintestinal target. The virulence phenotypes of both strains were determined by using the RWPE-1 prostate cell line. The results obtained indicated that LF82 and EC73 are able to adhere to, invade, and survive within prostate epithelial cells. Invasion was confirmed by immunofluorescence and electron microscopy. Moreover, cytochalasin D and colchicine strongly inhibited bacterial uptake of both strains, indicating the involvement of actin microfilaments and microtubules in host cell invasion. Moreover, both strains belong to phylogenetic group B2 and are strong biofilm producers.In silicoanalysis reveals that LF82 shares with UPEC strains several virulence factors: namely, type 1 pili, the group II capsule, the vacuolating autotransporter toxin, four iron uptake systems, and the pathogenic island (PAI). Furthermore, compared to EC73, LF82 induces in RWPE-1 cells a marked increase of phosphorylation of mitogen-activated protein kinases (MAPKs) and of NF-κB already by 5 min postinfection, thus inducing a strong inflammatory response. Ourin vitrodata support the hypothesis that AIEC strains might play a role in prostatitis, and, by exploiting host-cell signaling pathways controlling the innate immune response, likely facilitate bacterial multiplication and dissemination within the male genitourinary tract.

scholarly journals Control of large chromosomal duplications in Escherichia coli by the mismatch repair system.

Genetics ◽  
1991 ◽  
Vol 129 (2) ◽  
pp. 327-332 ◽  
Author(s):  
M A Petit ◽  
J Dimpfl ◽  
M Radman ◽  
H Echols
Keyword(s):  
Escherichia Coli ◽  
Mismatch Repair ◽  
Dna Sequences ◽  
Chromosomal Rearrangements ◽  
Point Mutations ◽  
Repair System ◽  
E Coli ◽  
Mismatch Repair System ◽  
Mismatch Recognition ◽  
Homeologous Recombination

Abstract Excessive recombination between repeated, interspersed, and diverged DNA sequences is a potential source of genomic instability. We have investigated the possibility that a mechanism exists to suppress genetic exchange between these quasi-homologous (homeologous) sequences. We examined the role of the general mismatch repair system of Escherichia coli because previous work has shown that the mismatch repair pathway functions as a barrier to interspecies recombination between E. coli and Salmonella typhimurium. The formation of large duplications by homeologous recombination in E. coli was increased some tenfold by mutations in the mutL and mutS genes that encode the mismatch recognition proteins. These findings indicate that the mismatch recognition proteins act to prevent excessive intrachromosomal exchanges. We conclude that mismatch repair proteins serve as general controllers of the fidelity of genetic inheritance, acting to suppress chromosomal rearrangements as well as point mutations.

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