EcoA: The first member of a new family of type I restriction modification systems

Suri, B.; Bickle, Thomas A.

doi:10.1016/0022-2836(85)90258-x

Cited by 67 publications

(62 citation statements)

References 34 publications

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“…Titheradge et al (2001) used an HsdM identity value of 45 % to place novel HsdM polypeptides into the four existing families of type I enzymes; HsdM proteins with >45 % identity were placed into the same family. Based on this sole criterion, many of the newly characterized type I R-M systems can be assigned to one of four families identified in the Enterobacteriaceae (Fuller-Pace et al, 1985;Price et al, 1987;Suri & Bickle, 1985;Titheradge et al, 1996Titheradge et al, , 2001. However, only 17 % of the pairwise combinations between the 32 HsdM proteins in Fig.…”

Section: Family Classification Of the C Jejuni Hsd Locimentioning

confidence: 99%

“…Therefore, classification of HsdM families based on amino acid sequence similarity alone has the potential drawback of eventually generating an enormous number of type I R-M families. Analyses based on other criteria, such as allelic complementation and immunological cross-reactivity (Fuller-Pace et al, 1985;Murray et al, 1982;Suri & Bickle, 1985), may be able to place distantly related type I systems (e.g. the type ID and type 'IF' systems) into the same family; however, analyses performed on such diverse taxa may be problematic.…”

Section: Family Classification Of the C Jejuni Hsd Locimentioning

confidence: 99%

“…The first type I R-M systems to be described, EcoKI and EcoBI, are members of the type IA family (Murray, 2000). The type IB family, first described in Escherichia coli, is represented by the EcoAI and EcoEI systems (Fuller-Pace et al, 1985;Suri & Bickle, 1985). The type IC family, represented by EcoR124I, includes both plasmid-encoded (Firman et al, 1983;Skrzypek & Piekarowicz, 1989) and chromosomally encoded (Kong et al, 2000;Piekarowicz et al, 2001;Tyndall et al, 1994) members.…”

Section: Introductionmentioning

confidence: 99%

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Diversity within the Campylobacter jejuni type I restriction–modification loci

et al. 2005

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The type I restriction–modification (hsd) systems of 73 Campylobacter jejuni strains were characterized according to their DNA and amino acid sequences, and/or gene organization. A number of new genes were identified which are not present in the sequenced strain NCTC 11168. The closely related organism Helicobacter pylori has three type I systems; however, no evidence was found that C. jejuni strains contain multiple type I systems, although hsd loci are present in at least two different chromosomal locations. Also, unlike H. pylori, intervening ORFs are present, in some strains, between hsdR and hsdS and between hsdS and hsdM. No definitive function can be ascribed to these ORFs, designated here as rloA–H (R-linked ORF) and mloA–B (M-linked ORF). Based on parsimony analysis of amino acid sequences to assess character relatedness, the C. jejuni type I R–M systems are assigned to one of three families: ‘IAB’, ‘IC’ or ‘IF’. This study confirms that HsdM proteins within a family are highly conserved but share little homology with HsdM proteins from other families. The ‘IC’ hsd loci are >99 % identical at the nucleotide level, as are the ‘IF’ hsd loci. Additionally, whereas the nucleotide sequences of the ‘IAB’ hsdR and hsdM genes show a high degree of similarity, the nucleotide sequences of the ‘IAB’ hsdS and rlo genes vary considerably. This diversity suggests that recombination between ‘IAB’ hsd loci would lead not only to new hsdS alleles but also to the exchange of rlo genes; five C. jejuni hsd loci are presumably the result of such recombination. The importance of these findings with regard to the evolution of C. jejuni type I R–M systems is discussed.

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Section: Family Classification Of the C Jejuni Hsd Locimentioning

confidence: 99%

Section: Family Classification Of the C Jejuni Hsd Locimentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Diversity within the Campylobacter jejuni type I restriction–modification loci

et al. 2005

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“…The specificity subunit, S, includes two target recognition domains (TRDs) that impart target-sequence specificity to the restriction and modification activities of the complex ; the M subunits include the active site for DNA methylation and the R subunits that for nuclease activity. Two complexes are functional in bacterial cells : one comprises all three subunits (R # M # S " ) and is an R-M system, and the other lacks R (M # S " ) and has only methyltransferase activity (Lautenberger & Linn, 1972 ;Suri & Bickle, 1985 ;Taylor et al, 1992). A separate promoter from which hsdR is transcribed suggests a means for regulating restriction activity, but experiments provide no evidence for the transcriptional regulation of any of those type I R-M systems for which data are available (Kulik & Bickle, 1996 ;Loenen et al, 1987 ;.…”

Section: Types Of R-m Systemsmentioning

confidence: 99%

Immigration control of DNA in bacteria: self versus non-self

Murray¹

2002

Microbiology

153

143

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“…They detected very little Res in the absence of Mod and suggested that the Mod subunit may regulate the amount of Res by protecting it from degradation by proteases. Some mechanism of control for type I systems was anticipated from early observations that the genes encoding the modification component of a type IB system, EcoAI, could not be transferred to a recipient containing a plasmid expressing the hsdR gene (Fuller-Pace et al, 1985;Suri and Bickle, 1985). More recently, it has been demonstrated that the efficient establishment of the genes encoding a type IA system (Prakash-Cheng et al, 1993) or a type IB system (Kulik and Bickle, 1996) in a new host is dependent on the product of the hsdC gene of E. coli, whereas the plasmid-encoded genes for a member of the IC family are efficiently transferred even to an hsdC ¹ recipient (Kulik and Bickle, 1996).…”

Section: Discussionmentioning

confidence: 99%

ClpX and ClpP are essential for the efficient acquisition of genes specifying type IA and IB restriction systems

Makovets

Titheradge

Murray

1998

Molecular Microbiology

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SummaryEfficient acquisition of genes that encode a restriction and modification (R-M) system with specificities different from any already present in the recipient bacterium requires the sequential production of the new modification enzyme followed by the restriction activity in order that the chromosome of the recipient bacterium is protected against attack by the restriction endonuclease. We show that ClpX and ClpP, the components of ClpXP protease, are necessary for the efficient transmission of the genes encoding EcoKI and EcoAI, representatives of two families of type I R-M systems, thus implicating ClpXP in the modulation of restriction activity. Loss of ClpX imposed a bigger barrier than loss of ClpP, consistent with a dual role for ClpX, possibly as a chaperone and as a component of the ClpXP protease. Transmission of genes specifying EcoKI was more dependent on ClpX and ClpP than transmission of the genes for EcoAI. Sensitivity to absence of the protease was also influenced by the mode of gene transfer; conjugative transfer and transformation were more dependent on ClpXP than transduction. In the absence of either ClpX or ClpP transfer of the EcoKI genes by P1-mediated transduction was impaired, transfer of the EcoAI genes was not.

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EcoA: The first member of a new family of type I restriction modification systems

Cited by 67 publications

References 34 publications

Diversity within the Campylobacter jejuni type I restriction–modification loci

Diversity within the Campylobacter jejuni type I restriction–modification loci

Immigration control of DNA in bacteria: self versus non-self

ClpX and ClpP are essential for the efficient acquisition of genes specifying type IA and IB restriction systems

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