Ontology highlight
ABSTRACT:
PROVIDER: PRJNA668898 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:Various species of the intestinal microbiota have been associated with the
development of colorectal cancer (CRC), yet a direct role of bacteria in the
occurrence of oncogenic mutations has not been established. Escherichia coli can
carry the pathogenicity island pks, which encodes a set of enzymes that
synthesize colibactin. This compound alkylates DNA on adenine residues and
induces double strand breaks in cultured cells. Here, we exposed human intestinal
organoids to genotoxic pks+ Escherichia coli by repeated luminal injection over a
period of 5 months. Whole genome sequencing (WGS) of clonal organoids before
and after this exposure reveals a distinct mutational signature, absent from
organoids injected with isogenic pks-mutant bacteria. The same mutational
signature is detected in a subset of 3668 human metastatic cancer genomes,
predominantly in a subset of CRC cases. Our study describes a distinct mutational
signature in CRC and implies that the underlying mutational process directly
results from past exposure to bacteria carrying the colibactin-producing pks
pathogenicity island.
| EGAS00001003934 | EGA
Project description:Various bacteria are suggested to contribute to colorectal cancer (CRC) development, including pks+ E. coli, which produces the genotoxin colibactin that induces characteristic mutational signatures in host epithelial cells. However, it remains unclear how the highly unstable colibactin molecule is able to access host epithelial cells to cause harm. Using the microbiota-dependent ZEB2-transgenic mouse model of invasive CRC, we demonstrate that the oncogenic potential of pks+ E. coli critically depends on bacterial adhesion to host epithelial cells, mediated by the type-1 pilus adhesin FimH and the F9-pilus adhesin FmlH. Blocking bacterial adhesion using a pharmacological FimH inhibitor attenuates colibactin-mediated genotoxicity and CRC exacerbation. We also show that allelic switching of FimH strongly influences genotoxic potential of pks+ E. coli and can induce a genotoxic gain-of-function in the probiotic strain Nissle 1917. Adhesin-mediated epithelial binding subsequently allows the production of the genotoxin colibactin in close proximity to host epithelial cells, which promotes DNA damage and drives CRC development. These findings present promising therapeutic avenues for the development of anti-adhesive therapies aimed at mitigating colibactin-induced DNA damage and inhibiting the initiation and progression of CRC, particularly in individuals at risk for developing CRC.
2024-08-19 | GSE241851 | GEO
Project description:Polyketide synthases (PKSs) are versatile biosynthetic megasynthases capable of producing a diverse range of natural products with many applications, including in pharmaceuticals. The stereochemical precision of PKSs makes them a powerful tool for engineering tailored, unnatural polyketides; however, modifying the stereocenters of a PKS product while maintaining production levels remains a significant challenge. In this study, we systematically tested and evaluated strategies for ketoreductase (KR) domain exchanges, the domain responsible for setting stereocenters of polyketide products. After first optimizing the method for KR exchanges, we then performed 44 KR domain exchanges on three different PKSs to obtain high production of all four stereoisomers in vivo. By testing both one- and two-module PKS systems, we investigated how downstream modules process intermediates with altered stereochemistry and found that the configuration of the α-substituents was critical for gatekeeping by the ketosynthase (KS). To overcome this constraint, we investigated two different strategies for altering the KS domain, including introducing targeted mutations in the downstream KS, and exploring boundaries in exchanging the entire functional unit from the donor PKS. Both strategies successfully modified the KS stereocontrol with distinct tradeoffs; the functional unit exchange resulted in higher improvements, though it was more likely to break the entire PKS. This study demonstrates a comprehensive approach to successfully engineering all four stereochemical configurations in multiple PKS systems, advancing our understanding of and ability to rationally modify polyketide stereochemistry through multiple engineering strategies.
2025-12-01 | PXD066826 | Pride
Project description:Protein kinases (PKs) are involved in plant growth and stress responses, and constitute one of the largest superfamilies due to numerous gene duplications. However, limited PKs have been functionally described in pecan, an economically important nut tree. Here, the comprehensive identification, annotation and classification of the entire pecan kinome was reported. A total of 967 PK genes were identified from pecan genome, and further classified into 20 different groups and 121 subfamilies using the kinase domain sequences, which were verified by the phylogenetic analysis. The receptor-like kinase (RLK) group contained 565 members, which constituted the largest group. Gene duplication contributed to the expansion of pecan kinome, 169 duplication events including 285 PK genes were found, and Ka/Ks ratio revealed they experienced strong negative selection. GO functional analysis indicated majority PKs involved in molecular functions and biological processes. The RNA-Seq data of PK genes in pecan were further analyzed at subfamily level, and different PK subfamilies performed various expression patterns across different conditions or treatments, suggesting PK genes in pecan involved in multiple biological functions and stress responses. Taken together, this study provided insight into the expansion, evolution and function of pecan PKs. Our findings regarding expansion, expression and co-expression analyses could lay a good foundation for future research to understand the roles of pecan PKs, and find the key candidate genes more efficiently.
2021-07-05 | GSE179336 | GEO
Project description:We observed that deletion of polyketide synthase (pks) from E. coli NC101 reduces its ability to induce tumors in interleukin-10 knockout (Il10-/-) mice injected with azoxymethane (AOM), without altering histologic inflammation. The goal of this experiment is to assess inflammatory cytokine levels in colonic tissue of these mice. 2 germ-free Il10-/- mice were assayed and used as controls. 3 E. coli NC101 and 3 E. coli NC101-delta-pks monoassociated mice were experimental samples.
2012-07-04 | E-GEOD-39095 | biostudies-arrayexpress
Project description:For systematically improving geldanamycin yield, we investigated the gene expression profile on the fourth day during geldanamycin fermentation (geldanamycin began to largely accumulated on this day). According to the RNA-seq data, we deduced that the PKS genes gdmAI-AIII are rate-limiting genes for geldanamycin biosynthesis. We also found a strong endogeneous promoter according to the RNA-seq data and the reporter gene. Replacing the native PKS promoter with this strong promoter brought an obvious increase in geldanamycin yield.
2017-03-03 | GSE92334 | GEO
Project description:Colibactin, a bacterial genotoxin produced by E. coli harboring the pks genomic island, induces cytopathic effects such as DNA breaks, cell cycle arrest and apoptosis. Patients with a colonic dysfunction due to inflammatory bowel disease such as ulcerative colitis have an elevated likelihood of carrying pks+ E. coli in their colon microbiota but it is not clear whether and how they contribute to the pathogenesis of colitis. Using a gnotobiotic mouse model, we show that pks+ E. coli do not affect colonic integrity under homeostatic conditions, with the microbiota remaining separated from the epithelium by a mucus barrier. However, upon chemical disruption of this barrier by DSS, the microbes gain direct access to the epithelium, causing severe epithelial injury, and development of colitis, while mice colonized with an isogenic ΔclbR mutant incapable of producing colibactin suffer significantly less pronounced effects. While ΔclbR-colonized animals show efficient recovery of the mucus barrier and crypt homeostasis, recovery in WT-colonized mice is impaired. Instead, the mucosa remains in a chronic regenerative state characterized by high proliferation and impaired differentiation of enterocytes and goblet cells, preventing the re-establishment of a functional barrier. In turn, pks+ E. coli remain in direct contact with the epithelium, perpetuating the process and triggering chronic mucosal inflammation that morphologically and transcriptionally resembles human ulcerative colitis. It is characterized by high levels of stromal R-spondin 3. Genetic overexpression of R-spondin 3 in colon myofibroblasts is sufficient to mimic this chronic regenerative state, resulting in barrier disruption and expansion of E. coli. Together, our data reveal that pks+ E. coli are pathobionts that upon contact with the epithelium promote severe injury and interfere with recovery, initiating chronic tissue dysfunction and inflammation.
2023-07-10 | GSE205403 | GEO
Project description:Persister cells are genetically identical variants in a bacterial population that have phenotypically modified their physiology to survive environmental stress. . To better define general persistence mechanisms that can be targeted to develop anti-persistence therapeutics, we performed transcriptomics analyses of Burkholderia thailandensis enriched for persisters using three methods: flow sorting by low proton motive force, meropenem treatment, and culture aging. Although the three persister populations generally expressed divergent gene expression profiles that underscores the multi-mechanistic nature of persistence, there were several common gene pathways expressed in two or more persister populations, including polyketide and non-ribosomal peptide synthesis, Clp proteases, mobile elements, enzymes involved in the lipid metabolism, and ATP-binding cassette (ABC) transporter systems. In particular, identification of genes that encode for polyketide synthases (PKS) and fatty acid catabolism indicate that generation of secondary metabolites, natural products, and complex lipids are needed for the maintenance of the persistence state. Persisters are markedly reduced in transposon mutants of the PKS gene BTH_I2366. Furthermore, treatment of multiple bacterial pathogens with the fatty acid synthesis inhibitor, CP-640186, potentiated antibiotic efficacy against the persisters. All together, our results suggest that bacterial persisters may exhibit an outward dormant physiology, but maintain active metabolic processes that are required to maintain persistence.
2019-03-06 | GSE127838 | GEO