A dichotomous epigenetic mechanism governs expression of the LlaJI restriction/modification system

O’Driscoll, Jonathan; Fitzgerald, Gerald F.; Sinderen, Douwe van

doi:10.1111/j.1365-2958.2005.04769.x

Cited by 16 publications

(17 citation statements)

References 64 publications

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“…In a number of cases binding of the methylase to DNA occurs via an N-terminal extension containing a helix-turn-helix motif (142,196,197). For example, in the SsoII R-M system of Shigella sonnei, the SsoII methyltransferase (SsoIIM) represses its own synthesis and stimulates expression of the cognate restriction endonuclease (SsoIIR).…”

Section: Origins: R-m Systemsmentioning

confidence: 99%

Epigenetic Gene Regulation in the Bacterial World

Casadesús

Low

2006

Microbiol Mol Biol Rev

568

562

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SUMMARY Like many eukaryotes, bacteria make widespread use of postreplicative DNA methylation for the epigenetic control of DNA-protein interactions. Unlike eukaryotes, however, bacteria use DNA adenine methylation (rather than DNA cytosine methylation) as an epigenetic signal. DNA adenine methylation plays roles in the virulence of diverse pathogens of humans and livestock animals, including pathogenic Escherichia coli, Salmonella, Vibrio, Yersinia, Haemophilus, and Brucella. In Alphaproteobacteria, methylation of adenine at GANTC sites by the CcrM methylase regulates the cell cycle and couples gene transcription to DNA replication. In Gammaproteobacteria, adenine methylation at GATC sites by the Dam methylase provides signals for DNA replication, chromosome segregation, mismatch repair, packaging of bacteriophage genomes, transposase activity, and regulation of gene expression. Transcriptional repression by Dam methylation appears to be more common than transcriptional activation. Certain promoters are active only during the hemimethylation interval that follows DNA replication; repression is restored when the newly synthesized DNA strand is methylated. In the E. coli genome, however, methylation of specific GATC sites can be blocked by cognate DNA binding proteins. Blockage of GATC methylation beyond cell division permits transmission of DNA methylation patterns to daughter cells and can give rise to distinct epigenetic states, each propagated by a positive feedback loop. Switching between alternative DNA methylation patterns can split clonal bacterial populations into epigenetic lineages in a manner reminiscent of eukaryotic cell differentiation. Inheritance of self-propagating DNA methylation patterns governs phase variation in the E. coli pap operon, the agn43 gene, and other loci encoding virulence-related cell surface functions.

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Section: Origins: R-m Systemsmentioning

confidence: 99%

Epigenetic Gene Regulation in the Bacterial World

Casadesús

Low

2006

Microbiol Mol Biol Rev

568

562

View full text Add to dashboard Cite

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“…This mechanism seems to be unique since methylation usually decreases the binding efficiency of a repressor with its operator [74]. The complicated regulatory mechanism is likely to enable fine tuning of transcriptional level in LlaJI R-M system [74]. Transcription regulation has been studied most thoroughly in the R-M systems SsoII from Shigella sonnei 47 and Ecl18kI from Enterobacter сloacea 18k.…”

Section: (Cytosine-5)-dna Methyltransferases As Transcription Factorsmentioning

confidence: 99%

“…These MTases have the same recognition site 5′-GACGC-3′/3′-CTGCG-5′ but methylate different cytosine bases (italicised) in the "top" and the "bottom" DNA strands respectively [73,74]. Genes coding for these MTases and two RE compose one operon and are transcribed from the same promoter ( Figure 5, a).…”

Section: (Cytosine-5)-dna Methyltransferases As Transcription Factorsmentioning

confidence: 99%

“…The M1.LlaJI binding to the inverted repeat results in suppression of gene transcription for the whole LlaJI operon. This mechanism seems to be unique since methylation usually decreases the binding efficiency of a repressor with its operator [74]. The complicated regulatory mechanism is likely to enable fine tuning of transcriptional level in LlaJI R-M system [74].…”

Section: (Cytosine-5)-dna Methyltransferases As Transcription Factorsmentioning

confidence: 99%

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Diverse Domains of (Cytosine-5)-DNA Methyltransferases: Structural and Functional Characterization

Ryazanova¹,

Abrosimova²,

Oretskaya³

et al. 2012

Methylation - From DNA, RNA and Histones to Diseases and Treatment

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“…The coordinated expression of RM genes in SsoII and EcoRII systems relies on the ability of the modification enzymes to repress the transcription of their own genes (4,28,63). In CfrBI and LIaJI RM systems, transcription regulation depends on the methylation status of cognate recognition site(s) within the promoter region (52). Expression of R.EcoRI and M.EcoRI is negatively regulated by intragenic reverse promoters (38,39).…”

mentioning

confidence: 99%

Maintenance Forced by a Restriction-Modification System Can Be Modulated by a Region in Its Modification Enzyme Not Essential for Methyltransferase Activity

et al. 2008

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Several type II restriction-modification gene complexes can force their maintenance on their host bacteria by killing cells that have lost them in a process called postsegregational killing or genetic addiction. It is likely to proceed by dilution of the modification enzyme molecule during rounds of cell division following the gene loss, which exposes unmethylated recognition sites on the newly replicated chromosomes to lethal attack by the remaining restriction enzyme molecules. This process is in apparent contrast to the process of the classical types of postsegregational killing systems, in which built-in metabolic instability of the antitoxin allows release of the toxin for lethal action after the gene loss. In the present study, we characterize a mutant form of the EcoRII gene complex that shows stronger capacity in such maintenance. This phenotype is conferred by an L80P amino acid substitution (T239C nucleotide substitution) mutation in the modification enzyme. This mutant enzyme showed decreased DNA methyltransferase activity at a higher temperature in vivo and in vitro than the nonmutated enzyme, although a deletion mutant lacking the N-terminal 83 amino acids did not lose activity at either of the temperatures tested. Under a condition of inhibited protein synthesis, the activity of the L80P mutant was completely lost at a high temperature. In parallel, the L80P mutant protein disappeared more rapidly than the wild-type protein. These results demonstrate that the capability of a restrictionmodification system in forcing maintenance on its host can be modulated by a region of its antitoxin, the modification enzyme, as in the classical postsegregational killing systems.

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A dichotomous epigenetic mechanism governs expression of the LlaJI restriction/modification system

Cited by 16 publications

References 64 publications

Epigenetic Gene Regulation in the Bacterial World

Epigenetic Gene Regulation in the Bacterial World

Diverse Domains of (Cytosine-5)-DNA Methyltransferases: Structural and Functional Characterization

Maintenance Forced by a Restriction-Modification System Can Be Modulated by a Region in Its Modification Enzyme Not Essential for Methyltransferase Activity

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