Restriction-modification system evasion by virus

The restriction-modification (RM) system is a defense mechanism present in over 90% of sequenced bacterial and archeal genomes. Its consists of a modification enzyme that methylates a specific DNA sequence in a genome and a restriction endonuclease that cleaves DNA lacking this methylation .<div id="PMID: 11782494" class="hidden">2001 Fred Griffith review lecture. Immigration control of DNA in bacteria: self versus non-self
Noreen E Murray
Microbiology (Reading, Engl.) January 2002; 148: 3?20

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Bacterial viruses have evolved different strategies to evade the restriction-modification system . Some viruses encode their own methyltransferase in order to protect their genome from host restriction enzymes . Instead, bacteriophage T7 encodes the OCR protein that blocks the active site of several restriction enzymes by mimicking the phosphate backbone of B-form DNA. Other bacterial viruses use unusual bases on their genome to avoid restriction. Bacteriophages SPO1, SP82, and 2C replace thymidine with 5-hydroxymethyluracil while phages PBS1 and PBS2 thymine is completely changed to uracil.

Family Genus Virus Strategy of RM evasion Viral protein Ref.
Siphoviridae Tunalikevirus Bacteriophage T1 Viral methyltransferase Dmt methyltransferase
Podoviridae T7likevirus Bacteriophage T3 Viral SAMase S-adenosyl-L-methionine hydrolase
Myoviridae T4likevirus Bacteriophage T4 Viral methyltransferase Dam methyltransferase
Myoviridae T4likevirus Bacteriophage T2 Viral methyltransferase Dam methyltransferase
Podoviridae T7likevirus Bacteriophage T7 Inhibition of type-I RM enzymes OCR protein
Myoviridae Punalikevirus Bacteriophage P1 Internal capsid protein DarA, DarB
Podoviridae P22likevirus Bacteriophage P22 Modification of host methylase activity Ral
Siphoviridae Lambdalikevirus Bacteriophage λ reverse Modification of host methylase activity Lar
Siphoviridae Lambdalikevirus Bacteriophage λ Modification of host methylase activity Ral
Myoviridae Mulikevirus Bacteriophage Mu Adenine acetyltransferase Mom

Matching UniProtKB/Swiss-Prot entries

16 entries grouped by protein (browse by keywords)

1 entry

S-adenosyl-L-methionine hydrolase (ADOMetase) (Adenosylmethionine hydrolase) (SAMase) (EC 3.3.1.2)

ADOM_BPT3
Enterobacteria phage T3 (Bacteriophage T3) reference strain

1 entry

Anti-restriction endonuclease (Anti-rgl nuclease)

ARN_BPT4
Enterobacteria phage T4 (Bacteriophage T4) reference strain

1 entry

Defense against restriction protein A (DarA)

DARA_BPP1
Escherichia phage P1 (Bacteriophage P1) reference strain

1 entry

Defense against restriction protein B (EC 3.6.4.-) (DarB)

DARB_BPP1
Escherichia phage P1 (Bacteriophage P1) reference strain

2 entries

DNA adenine methylase (EC 2.1.1.72) (DNA-(N(6)-adenine)-methyltransferase) (Deoxyadenosyl-methyltransferase) (M.EcoT2Dam)

Select_allDeselect_all
DMA_BPT4
Enterobacteria phage T4 (Bacteriophage T4) reference strain

DNA adenine methylase (EC 2.1.1.72) (DNA-(N(6)-adenine)-methyltransferase) (Deoxyadenosyl-methyltransferase) (M.EcoT4Dam)

DMA_BPT2
Enterobacteria phage T2 (Bacteriophage T2)

1 entry

Methyltransferase Dmt (EC 2.1.1.-)

DMT_BPP1
Escherichia phage P1 (Bacteriophage P1) reference strain

1 entry

DNA alpha-glucosyltransferase (AGT) (Alpha-GT) (EC 2.4.1.26)

GSTA_BPT4
Enterobacteria phage T4 (Bacteriophage T4) reference strain

1 entry

DNA beta-glucosyltransferase (BGT) (Beta-GT) (EC 2.4.1.27)

GSTB_BPT4
Enterobacteria phage T4 (Bacteriophage T4) reference strain

2 entries

Methylcarbamoylase mom (Adenine modification enzyme mom) (Gene product 55) (gp55) (Gene product mom) (gpMom) (Modification of Mu) (Mom)

Select_allDeselect_all
MOM_BPD10
Escherichia phage D108 (Bacteriophage D108) reference strain

Methylcarbamoylase mom (Adenine modification enzyme mom) (Gene product mom) (gpMom) (Modification of Mu) (Mom)

MOM_BPMU
Escherichia phage Mu (Bacteriophage Mu) reference strain

1 entry

Protein Ocr (Gene product 0.3) (Gp0.3) (Overcome classical restriction) (Ocr)

OCR_BPT7
Escherichia phage T7 (Bacteriophage T7) reference strain

3 entries

Restriction inhibitor protein ral (Antirestriction protein)

Select_allDeselect_all
RAL_BPP22
Salmonella phage P22 (Bacteriophage P22) reference strain
RAL_LAMBD
Escherichia phage lambda (Bacteriophage lambda) reference strain
RAL_BPPH3
Enterobacteria phage phi21 (Bacteriophage phi-21)

1 entry

T4 Suppressor of prr (Stp)

STP_BPT4
Enterobacteria phage T4 (Bacteriophage T4) reference strain