Influence of phage T3 and T7 gene functions on a type III (EcoP1) DNA restriction-modification system in vivo

1982 ◽  
Vol 185 (3) ◽  
pp. 457-461 ◽  
Author(s):  
Detlev H. Krüger ◽  
Monika Reuter ◽  
Sigrid Hansen ◽  
Cornelia Schroeder
Keyword(s):  
Modification System ◽  
Type Iii ◽  
Restriction Modification System ◽  
Gene Functions ◽  
Dna Restriction ◽  
Restriction Modification

scholarly journals Transcriptional Phase Variation of a Type III Restriction-Modification System in Helicobacter pylori

2002 ◽  
Vol 184 (23) ◽  
pp. 6615-6623 ◽  
Author(s):  
Nicolette de Vries ◽  
Dirk Duinsbergen ◽  
Ernst J. Kuipers ◽  
Raymond G. J. Pot ◽  
Patricia Wiesenekker ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Phase Variation ◽  
Transcriptional Level ◽  
Length Variation ◽  
Phase Variable ◽  
Modification System ◽  
Type Iii ◽  
Restriction Modification System ◽  
H Pylori ◽  
Restriction Modification

ABSTRACT Phase variation is important in bacterial pathogenesis, since it generates antigenic variation for the evasion of immune responses and provides a strategy for quick adaptation to environmental changes. In this study, a Helicobacter pylori clone, designated MOD525, was identified that displayed phase-variable lacZ expression. The clone contained a transcriptional lacZ fusion in a putative type III DNA methyltransferase gene (mod, a homolog of the gene JHP1296 of strain J99), organized in an operon-like structure with a putative type III restriction endonuclease gene (res, a homolog of the gene JHP1297), located directly upstream of it. This putative type III restriction-modification system was common in H. pylori, as it was present in 15 out of 16 clinical isolates. Phase variation of the mod gene occurred at the transcriptional level both in clone MOD525 and in the parental H. pylori strain 1061. Further analysis showed that the res gene also displayed transcriptional phase variation and that it was cotranscribed with the mod gene. A homopolymeric cytosine tract (C tract) was present in the 5′ coding region of the res gene. Length variation of this C tract caused the res open reading frame (ORF) to shift in and out of frame, switching the res gene on and off at the translational level. Surprisingly, the presence of an intact res ORF was positively correlated with active transcription of the downstream mod gene. Moreover, the C tract was required for the occurrence of transcriptional phase variation. Our finding that translation and transcription are linked during phase variation through slipped-strand mispairing is new for H. pylori.

Phase variation in a type III restriction-modification system of Helicobacter pylori

2000 ◽  
Vol 118 (4) ◽  
pp. A736 ◽  
Author(s):  
Nicolette Vries de ◽  
Dirk Duinsbergen ◽  
Ernst J. Kuipers ◽  
Patricia Wiesenekker ◽  
Christina M. Vandenbroucke-Grauls ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Phase Variation ◽  
Modification System ◽  
Type Iii ◽  
Restriction Modification System ◽  
Restriction Modification

A novel plasmid-mediated DNA restriction-modification system in E. coli

Plasmid ◽  
1980 ◽  
Vol 4 (3) ◽  
pp. 350-351 ◽  
Author(s):  
L.I. Glatman ◽  
A.F. Moroz ◽  
M.B. Yablokova ◽  
B.A. Rebentish ◽  
G.V. Kc̵holmina
Keyword(s):  
Modification System ◽  
E Coli ◽  
Restriction Modification System ◽  
Dna Restriction ◽  
Restriction Modification

scholarly journals In Vivo DNA Protection by Relaxed-Specificity SinI DNA Methyltransferase Variants

2008 ◽  
Vol 190 (24) ◽  
pp. 8003-8008 ◽  
Author(s):  
Edit Tímár ◽  
Pál Venetianer ◽  
Antal Kiss
Keyword(s):  
Restriction Endonuclease ◽  
Dna Methyltransferase ◽  
Term Survival ◽  
Modification System ◽  
Restriction Modification System ◽  
Low Concentrations ◽  
Compatible Plasmid ◽  
Restriction Modification

ABSTRACT The SinI DNA methyltransferase, a component of the SinI restriction-modification system, recognizes the sequence GG(A/T)CC and methylates the inner cytosine to produce 5-methylcytosine. Previously isolated relaxed-specificity mutants of the enzyme also methylate, at a lower rate, GG(G/C)CC sites. In this work we tested the capacity of the mutant enzymes to function in vivo as the counterpart of a restriction endonuclease, which can cleave either site. The viability of Escherichia coli cells carrying recombinant plasmids with the mutant methyltransferase genes and expressing the GGNCC-specific Sau96I restriction endonuclease from a compatible plasmid was investigated. The sau96IR gene on the latter plasmid was transcribed from the araBAD promoter, allowing tightly controlled expression of the endonuclease. In the presence of low concentrations of the inducer arabinose, cells synthesizing the N172S or the V173L mutant enzyme displayed increased plating efficiency relative to cells producing the wild-type methyltransferase, indicating enhanced protection of the cell DNA against the Sau96I endonuclease. Nevertheless, this protection was not sufficient to support long-term survival in the presence of the inducer, which is consistent with incomplete methylation of GG(G/C)CC sites in plasmid DNA purified from the N172S and V173L mutants. Elevated DNA ligase activity was shown to further increase viability of cells producing the V173L variant and Sau96I endonuclease.

scholarly journals Type II Restriction-Modification System from Gardnerella vaginalis ATCC 14018

Pathogens ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 703
Author(s):  
Aistė Bulavaitė ◽  
Indre Dalgediene ◽  
Vilma Michailoviene ◽  
Milda Pleckaityte
Keyword(s):  
Polyclonal Antibodies ◽  
Gardnerella Vaginalis ◽  
Wild Type ◽  
Modification System ◽  
Restriction Modification System ◽  
Digestion Pattern ◽  
Foreign Dna ◽  
Restriction Modification ◽  
Rease Activity

Intensive horizontal gene transfer may generate diversity and heterogeneity within the genus Gardnerella. Restriction-modification (R-M) systems and CRISPR-Cas are the principal defense tools against foreign DNA in bacteria. Nearly half of the tested Gardnerella spp. isolates harbored the CRISPR-Cas system. Several putative R-M systems of Gardnerella spp. strains were identified in the REBASE database. However, there was no experimental evidence for restriction endonuclease (REase) activity in the isolates. We showed that G. vaginalis strain ATCC 14018 contains the REase R.Gva14018I, which recognizes GGCC and most probably generates blunt ends on cleavage. Bioinformatics evidence and the activity of recombinant methyltransferase M.Gva14018I in vivo indicate that ATCC 14018 possesses a HaeIII-like R-M system. The truncated R.Gva14018I-4 lacking the C-terminal region was expressed in Escherichia coli and displayed wild-type REase specificity. Polyclonal antibodies against R.Gva14018I-4 detected the wild-type REase in the cell lysate of ATCC 14018. The cofactor requirements for activity and bioinformatics analysis indicated that R.Gva14018I belongs to the PD-(D/E)XK family of REases. The REase-like activity was observed in 5 of 31 tested Gardnerella spp. strains, although none of these matched the DNA digestion pattern of R.Gva14018I.

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