Effect of DNA topology on holliday junction resolution by Escherichia coli RuvC and bacteriophage T7 endonuclease I

Zerbib, D., Colloms, S. D. , Sherratt, D. J. and West, S. C. (1997) Effect of DNA topology on holliday junction resolution by Escherichia coli RuvC and bacteriophage T7 endonuclease I. Journal of Molecular Biology, 270(5), pp. 663-673. (doi:10.1006/jmbi.1997.1157) (PMID:9245595)

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Abstract

Holliday junctions are key intermediates in homologous genetic recombination. Their resolution requires specialised nucleases that nick pairs of strands at the junction point, leading to the separation of mature recombinants. Resolution occurs in either of two orientations, according to which DNA strands are cut. We show that DNA topology can determine the efficiency and outcome of a recombination reaction. Using two Holliday junction resolvases, Escherichia coli RuvC protein and T7 endonuclease I, we observed that supercoiled figure-8 DNA molecules containing Holliday junctions were resolved with a specific orientation bias, and that this bias was reversed by the presence of a topological tether (catenation). In contrast, when all topological constraints were removed by restriction digestion, the recombination intermediates were resolved equally in the two orientations. These results show that topological constraints affecting Holliday junction structure influence the orientation of resolution by cellular resolvases.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Colloms, Dr Sean
Authors: Zerbib, D., Colloms, S. D., Sherratt, D. J., and West, S. C.
College/School:College of Medical Veterinary and Life Sciences > Institute of Molecular Cell and Systems Biology
Journal Name:Journal of Molecular Biology
Publisher:Elsevier
ISSN:0022-2836
ISSN (Online):1089-8638

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