Identification and distribution of an orphan cytosine methylase in Listeria monocytogenes that creates partial CpG DNA methylation

Kód výsledku v IS VaVaI

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Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

Identification and distribution of an orphan cytosine methylase in Listeria monocytogenes that creates partial CpG DNA methylation

Popis výsledku v původním jazyce

Background: The absence of partial CpG methylation of DNA is a known PAMP recognised by the human immune system to detect the presence of infecting bacteria. Orphan methylase genes (i.e. those not associated with a cognate restriction enzyme) have been previously identified in Listeria genomes. We have been investigating the genome location and distribution of one such orphan cytosine methylase in Listeria which creates a eukaryotic-like CpG DNA methylation pattern.Methods and Results: The cytosine methylase gene was cloned using a methylase trapping strategy. Briefly, genomic fragments from a partial CpG methylation-positive strain of L. monocytogenes (LM23) were cloned into a vector containing a ClaI site and transformed into E. coli JM110 (dcm-, dam-). Pooled plasmid DNA was cut with ClaI, (sensitive to CpG methylation) and then retransformed into E. coli. This strategy recovered a gene with homology to a cytosine methylase (termed lcmA). WGS was performed on a selection of the CpG-positive CpG-negative strains. When present, the lcmA gene is always associated with two accessory genes located between two metabolic gene systems (thiE and a beta-glucosidase). The presence of the lcmA gene cluster correlated with the detection of a partial CpG methylation pattern, confirming that this gene system is responsible for this phenomenon. Interestingly the lcmA gene cluster is found just downstream of the site of the virulence gene vip when this is present. Further analysis of Listeria genome sequences identified strains with different patterns; (a) lcmA+, vip+, (b) lcmA+, vip- and (c) lcmA-, vip+, as well as strains with carried neither gene.Conclusions: This region of the Listeria chromosome seems to be a hotspot for gene acquisition. As an intracellular pathogen, we hypothesis that this phenotype may mimic host patterns of CpG methylation and allow the bacterium to avoid the host cell-mediated immune response, potentially causing increased virulence.

Název v anglickém jazyce

Identification and distribution of an orphan cytosine methylase in Listeria monocytogenes that creates partial CpG DNA methylation

Popis výsledku anglicky

Background: The absence of partial CpG methylation of DNA is a known PAMP recognised by the human immune system to detect the presence of infecting bacteria. Orphan methylase genes (i.e. those not associated with a cognate restriction enzyme) have been previously identified in Listeria genomes. We have been investigating the genome location and distribution of one such orphan cytosine methylase in Listeria which creates a eukaryotic-like CpG DNA methylation pattern.Methods and Results: The cytosine methylase gene was cloned using a methylase trapping strategy. Briefly, genomic fragments from a partial CpG methylation-positive strain of L. monocytogenes (LM23) were cloned into a vector containing a ClaI site and transformed into E. coli JM110 (dcm-, dam-). Pooled plasmid DNA was cut with ClaI, (sensitive to CpG methylation) and then retransformed into E. coli. This strategy recovered a gene with homology to a cytosine methylase (termed lcmA). WGS was performed on a selection of the CpG-positive CpG-negative strains. When present, the lcmA gene is always associated with two accessory genes located between two metabolic gene systems (thiE and a beta-glucosidase). The presence of the lcmA gene cluster correlated with the detection of a partial CpG methylation pattern, confirming that this gene system is responsible for this phenomenon. Interestingly the lcmA gene cluster is found just downstream of the site of the virulence gene vip when this is present. Further analysis of Listeria genome sequences identified strains with different patterns; (a) lcmA+, vip+, (b) lcmA+, vip- and (c) lcmA-, vip+, as well as strains with carried neither gene.Conclusions: This region of the Listeria chromosome seems to be a hotspot for gene acquisition. As an intracellular pathogen, we hypothesis that this phenotype may mimic host patterns of CpG methylation and allow the bacterium to avoid the host cell-mediated immune response, potentially causing increased virulence.

Druh

O - Ostatní výsledky

CEP obor

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OECD FORD obor

10606 - Microbiology

Projekt

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Návaznosti

V - Vyzkumna aktivita podporovana z jinych verejnych zdroju

Rok uplatnění

2024

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů