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Proc Natl Acad Sci U S A. Dec 1986; 83(23): 9070–9074.
PMCID: PMC387076

Escherichia coli K-12 restricts DNA containing 5-methylcytosine.


We have observed that plasmids containing certain cloned modification methylase genes of type II restriction-modification systems cannot be transformed into many laboratory strains of Escherichia coli K-12. The investigation of this phenomenon, reported here, has revealed (i) DNA containing 5-methylcytosine is biologically restricted by these strains, while DNA containing 6-methyladenine is not; (ii) restriction is due to two genetically distinct systems that differ in their sequence specificities, which we have named mcrA and mcrB (for modified cytosine restriction). Since 5-methylcytosine containing DNA is widespread in nature, the Mcr systems probably have a broad biological role. Mcr restriction may seriously interfere with molecular cloning of 5-methylcytosine-containing foreign DNAs. The Mcr phenotypes of some commonly used strains of E. coli K-12 are reported.

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  • LURIA SE, HUMAN ML. A nonhereditary, host-induced variation of bacterial viruses. J Bacteriol. 1952 Oct;64(4):557–569. [PMC free article] [PubMed]
  • Arber W. DNA modification and restriction. Prog Nucleic Acid Res Mol Biol. 1974;14(0):1–37. [PubMed]
  • Revel HR. Restriction of nonglucosylated T-even bacteriophage: properties of permissive mutants of Escherichia coli B and K12. Virology. 1967 Apr;31(4):688–701. [PubMed]
  • Bachmann BJ. Pedigrees of some mutant strains of Escherichia coli K-12. Bacteriol Rev. 1972 Dec;36(4):525–557. [PMC free article] [PubMed]
  • Wood WB. Host specificity of DNA produced by Escherichia coli: bacterial mutations affecting the restriction and modification of DNA. J Mol Biol. 1966 Mar;16(1):118–133. [PubMed]
  • Backman K, Ptashne M, Gilbert W. Construction of plasmids carrying the cI gene of bacteriophage lambda. Proc Natl Acad Sci U S A. 1976 Nov;73(11):4174–4178. [PMC free article] [PubMed]
  • Yanisch-Perron C, Vieira J, Messing J. Improved M13 phage cloning vectors and host strains: nucleotide sequences of the M13mp18 and pUC19 vectors. Gene. 1985;33(1):103–119. [PubMed]
  • Blumenthal RM, Gregory SA, Cooperider JS. Cloning of a restriction-modification system from Proteus vulgaris and its use in analyzing a methylase-sensitive phenotype in Escherichia coli. J Bacteriol. 1985 Nov;164(2):501–509. [PMC free article] [PubMed]
  • Young RA, Davis RW. Yeast RNA polymerase II genes: isolation with antibody probes. Science. 1983 Nov 18;222(4625):778–782. [PubMed]
  • Marinus MG, Carraway M, Frey AZ, Brown L, Arraj JA. Insertion mutations in the dam gene of Escherichia coli K-12. Mol Gen Genet. 1983;192(1-2):288–289. [PubMed]
  • Casadaban MJ, Cohen SN. Analysis of gene control signals by DNA fusion and cloning in Escherichia coli. J Mol Biol. 1980 Apr;138(2):179–207. [PubMed]
  • Roberts D, Hoopes BC, McClure WR, Kleckner N. IS10 transposition is regulated by DNA adenine methylation. Cell. 1985 Nov;43(1):117–130. [PubMed]
  • Kleckner N, Barker DF, Ross DG, Botstein D. Properties of the translocatable tetracycline-resistance element Tn10 in Escherichia coli and bacteriophage lambda. Genetics. 1978 Nov;90(3):427–461. [PMC free article] [PubMed]
  • Bolivar F, Rodriguez RL, Greene PJ, Betlach MC, Heyneker HL, Boyer HW, Crosa JH, Falkow S. Construction and characterization of new cloning vehicles. II. A multipurpose cloning system. Gene. 1977;2(2):95–113. [PubMed]
  • Tu CD, Roychoudhury R, Wu R. Nucleotide recognition sequence at the cleavage site of Haemophilus aegyptius II (Hae II) restriction endonuclease. Biochem Biophys Res Commun. 1976 Sep 7;72(1):355–362. [PubMed]
  • Roberts RJ. Restriction and modification enzymes and their recognition sequences. Nucleic Acids Res. 1984;12 (Suppl):r167–r204. [PMC free article] [PubMed]
  • Hattman S. Partial purification of the Escherichia coli K-12 mec+ deoxyribonucleic acid-cytosine methylase: in vitro methylation completely protects bacteriophage lambda deoxyribonucleic acid against cleavage by R-EcoRII. J Bacteriol. 1977 Mar;129(3):1330–1334. [PMC free article] [PubMed]
  • Walder RY, Langtimm CJ, Chatterjee R, Walder JA. Cloning of the MspI modification enzyme. The site of modification and its effects on cleavage by MspI and HpaII. J Biol Chem. 1983 Jan 25;258(2):1235–1241. [PubMed]
  • Butkus V, Klimasauskas S, Kersulyte D, Vaitkevicius D, Lebionka A, Janulaitis A. Investigation of restriction-modification enzymes from M. varians RFL19 with a new type of specificity toward modification of substrate. Nucleic Acids Res. 1985 Aug 26;13(16):5727–5746. [PMC free article] [PubMed]
  • Janulaitis A, Klimasauskas S, Petrusyte M, Butkus V. Cytosine modification in DNA by BcnI methylase yields N4-methylcytosine. FEBS Lett. 1983 Sep 5;161(1):131–134. [PubMed]
  • Ehrlich M, Wang RY. 5-Methylcytosine in eukaryotic DNA. Science. 1981 Jun 19;212(4501):1350–1357. [PubMed]
  • Fleischman RA, Richardson CC. Analysis of host range restriction in Escherichia coli treated with toluene. Proc Natl Acad Sci U S A. 1971 Oct;68(10):2527–2531. [PMC free article] [PubMed]
  • Fleischman RA, Cambell JL, Richardson CC. Modification and restriction of T-even bacteriophages. In vitro degradation of deoxyribonucleic acid containing 5-hydroxymethylctosine. J Biol Chem. 1976 Mar 25;251(6):1561–1570. [PubMed]
  • Duncan BK. Isolation of insertion, deletion, and nonsense mutations of the uracil-DNA glycosylase (ung) gene of Escherichia coli K-12. J Bacteriol. 1985 Nov;164(2):689–695. [PMC free article] [PubMed]
  • Lacks S, Greenberg B. A deoxyribonuclease of Diplococcus pneumoniae specific for methylated DNA. J Biol Chem. 1975 Jun 10;250(11):4060–4066. [PubMed]
  • Lacks S, Greenberg B. Complementary specificity of restriction endonucleases of Diplococcus pneumoniae with respect to DNA methylation. J Mol Biol. 1977 Jul;114(1):153–168. [PubMed]
  • Sladek TL, Nowak JA, Maniloff J. Mycoplasma restriction: identification of a new type of restriction specificity for DNA containing 5-methylcytosine. J Bacteriol. 1986 Jan;165(1):219–225. [PMC free article] [PubMed]
  • Krüger DH, Bickle TA. Bacteriophage survival: multiple mechanisms for avoiding the deoxyribonucleic acid restriction systems of their hosts. Microbiol Rev. 1983 Sep;47(3):345–360. [PMC free article] [PubMed]
  • Warren RA. Modified bases in bacteriophage DNAs. Annu Rev Microbiol. 1980;34:137–158. [PubMed]

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