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Spermidine biases the resolution of Holliday junctions by phage λ integrase

Holliday junctions are a central intermediate in diverse pathways of DNA repair and recombination. The isomerization of a junction determines the directionality of the recombination event. Previous studies have shown that the identity of the central sequence of the junction may favor one of the two...

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Autores principales: Boldt, Jeffrey L., Kepple, Kevin V., Cassell, Geoffrey D., Segall, Anca M.
Formato: Texto
Lenguaje:English
Publicado: Oxford University Press 2007
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1807965/
https://www.ncbi.nlm.nih.gov/pubmed/17182631
http://dx.doi.org/10.1093/nar/gkl1078
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author Boldt, Jeffrey L.
Kepple, Kevin V.
Cassell, Geoffrey D.
Segall, Anca M.
author_facet Boldt, Jeffrey L.
Kepple, Kevin V.
Cassell, Geoffrey D.
Segall, Anca M.
author_sort Boldt, Jeffrey L.
collection PubMed
description Holliday junctions are a central intermediate in diverse pathways of DNA repair and recombination. The isomerization of a junction determines the directionality of the recombination event. Previous studies have shown that the identity of the central sequence of the junction may favor one of the two isomers, in turn controlling the direction of the pathway. Here we demonstrate that, in the absence of DNA sequence-mediated isomer preference, polycations are the major contributor to biasing strand cleavage during junction resolution. In the case of wild-type phage λ excision junctions, spermidine plays the dominant role in controlling the isomerization state of the junction and increases the rate of junction resolution. Spermidine also counteracts the sequence-imposed bias on resolution. The spermidine-induced bias is seen equally on supercoiled and linear excisive recombination junction intermediates, and thus is not just an artefact of in vitro recombination conditions. The contribution of spermidine requires the presence of accessory factors, and results in the repositioning of Int's core-binding domains on junctions, perhaps due to DNA-spermidine–protein interactions, or by influencing DNA conformation in the core region. Our results lead us to propose that spermidine together with accessory factors promotes the formation of the second junction isomer. We propose that this rearrangement triggers the activation of the second pair of Int active sites necessary to resolve Holliday junctions during phage λ Int-mediated recombination.
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spelling pubmed-18079652007-03-02 Spermidine biases the resolution of Holliday junctions by phage λ integrase Boldt, Jeffrey L. Kepple, Kevin V. Cassell, Geoffrey D. Segall, Anca M. Nucleic Acids Res Nucleic Acid Enzymes Holliday junctions are a central intermediate in diverse pathways of DNA repair and recombination. The isomerization of a junction determines the directionality of the recombination event. Previous studies have shown that the identity of the central sequence of the junction may favor one of the two isomers, in turn controlling the direction of the pathway. Here we demonstrate that, in the absence of DNA sequence-mediated isomer preference, polycations are the major contributor to biasing strand cleavage during junction resolution. In the case of wild-type phage λ excision junctions, spermidine plays the dominant role in controlling the isomerization state of the junction and increases the rate of junction resolution. Spermidine also counteracts the sequence-imposed bias on resolution. The spermidine-induced bias is seen equally on supercoiled and linear excisive recombination junction intermediates, and thus is not just an artefact of in vitro recombination conditions. The contribution of spermidine requires the presence of accessory factors, and results in the repositioning of Int's core-binding domains on junctions, perhaps due to DNA-spermidine–protein interactions, or by influencing DNA conformation in the core region. Our results lead us to propose that spermidine together with accessory factors promotes the formation of the second junction isomer. We propose that this rearrangement triggers the activation of the second pair of Int active sites necessary to resolve Holliday junctions during phage λ Int-mediated recombination. Oxford University Press 2007-02 2006-12-19 /pmc/articles/PMC1807965/ /pubmed/17182631 http://dx.doi.org/10.1093/nar/gkl1078 Text en © 2006 The Author(s). 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 Nucleic Acid Enzymes
Boldt, Jeffrey L.
Kepple, Kevin V.
Cassell, Geoffrey D.
Segall, Anca M.
Spermidine biases the resolution of Holliday junctions by phage λ integrase
title Spermidine biases the resolution of Holliday junctions by phage λ integrase
title_full Spermidine biases the resolution of Holliday junctions by phage λ integrase
title_fullStr Spermidine biases the resolution of Holliday junctions by phage λ integrase
title_full_unstemmed Spermidine biases the resolution of Holliday junctions by phage λ integrase
title_short Spermidine biases the resolution of Holliday junctions by phage λ integrase
title_sort spermidine biases the resolution of holliday junctions by phage λ integrase
topic Nucleic Acid Enzymes
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1807965/
https://www.ncbi.nlm.nih.gov/pubmed/17182631
http://dx.doi.org/10.1093/nar/gkl1078
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