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Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system

Most type II restriction-modification (R-M) systems produce separate endonuclease (REase) and methyltransferase (MTase) proteins. After R-M genes enter a new cell, MTase activity must appear before REase or the host chromosome will be cleaved. Temporal control of these genes thus has life-or-death c...

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Autores principales: Mruk, Iwona, Blumenthal, Robert M.
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2009
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2647307/
https://www.ncbi.nlm.nih.gov/pubmed/19126580
http://dx.doi.org/10.1093/nar/gkn1010
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author Mruk, Iwona
Blumenthal, Robert M.
author_facet Mruk, Iwona
Blumenthal, Robert M.
author_sort Mruk, Iwona
collection PubMed
description Most type II restriction-modification (R-M) systems produce separate endonuclease (REase) and methyltransferase (MTase) proteins. After R-M genes enter a new cell, MTase activity must appear before REase or the host chromosome will be cleaved. Temporal control of these genes thus has life-or-death consequences. PvuII and some other R-M systems delay endonuclease expression by cotranscribing the REase gene with the upstream gene for an autogenous activator/repressor (C protein). C.PvuII was previously shown to have low levels early, but positive feedback later boosts transcription of the C and REase genes. The MTase is expressed without delay, and protects the host DNA. C.PvuII binds to two sites upstream of its gene: O(L), associated with activation, and O(R), associated with repression. Even when symmetry elements of each operator are made identical, C.PvuII binds preferentially to O(L). In this study, the intra-operator spacers are shown to modulate relative C.PvuII affinity. In light of a recently reported C.Esp1396I-DNA co-crystal structure, in vitro and in vivo effects of altering O(L) and O(R) spacers were determined. The results suggest that the GACTnnnAGTC consensus is the primary determinant of C.PvuII binding affinity, with intra-operator spacers playing a fine-tuning role that affects mobility of this R-M system.
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spelling pubmed-26473072009-03-04 Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system Mruk, Iwona Blumenthal, Robert M. Nucleic Acids Res Gene regulation, Chromatin and Epigenetics Most type II restriction-modification (R-M) systems produce separate endonuclease (REase) and methyltransferase (MTase) proteins. After R-M genes enter a new cell, MTase activity must appear before REase or the host chromosome will be cleaved. Temporal control of these genes thus has life-or-death consequences. PvuII and some other R-M systems delay endonuclease expression by cotranscribing the REase gene with the upstream gene for an autogenous activator/repressor (C protein). C.PvuII was previously shown to have low levels early, but positive feedback later boosts transcription of the C and REase genes. The MTase is expressed without delay, and protects the host DNA. C.PvuII binds to two sites upstream of its gene: O(L), associated with activation, and O(R), associated with repression. Even when symmetry elements of each operator are made identical, C.PvuII binds preferentially to O(L). In this study, the intra-operator spacers are shown to modulate relative C.PvuII affinity. In light of a recently reported C.Esp1396I-DNA co-crystal structure, in vitro and in vivo effects of altering O(L) and O(R) spacers were determined. The results suggest that the GACTnnnAGTC consensus is the primary determinant of C.PvuII binding affinity, with intra-operator spacers playing a fine-tuning role that affects mobility of this R-M system. Oxford University Press 2009-02 2009-01-06 /pmc/articles/PMC2647307/ /pubmed/19126580 http://dx.doi.org/10.1093/nar/gkn1010 Text en © 2009 The Author(s) http://creativecommons.org/licenses/by-nc/2.0/uk/ This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/2.0/uk/) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
spellingShingle Gene regulation, Chromatin and Epigenetics
Mruk, Iwona
Blumenthal, Robert M.
Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system
title Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system
title_full Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system
title_fullStr Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system
title_full_unstemmed Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system
title_short Tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system
title_sort tuning the relative affinities for activating and repressing operators of a temporally regulated restriction-modification system
topic Gene regulation, Chromatin and Epigenetics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2647307/
https://www.ncbi.nlm.nih.gov/pubmed/19126580
http://dx.doi.org/10.1093/nar/gkn1010
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