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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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Formato: | Texto |
Lenguaje: | English |
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Oxford University Press
2009
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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. |
format | Text |
id | pubmed-2647307 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2009 |
publisher | Oxford University Press |
record_format | MEDLINE/PubMed |
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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