Nucleic Acids Research Advance Access originally published online on July 18, 2007
Nucleic Acids Research 2007 35(15):5001-5013; doi:10.1093/nar/gkm525
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Nucleic Acids Research, 2007, Vol. 35, No. 15 5001-5013
© 2007 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.
Nucleic Acid Enzymes |
HMGB1 interacts with human topoisomerase II
and stimulates its catalytic activity
tros1,*
íková1tokrová21Laboratory of Analysis of Chromosomal Proteins, Academy of Sciences of the Czech Republic, Institute of Biophysics, Brno, 2Institute of Molecular Genetics, Academy of Sciences of the Czech Republic, Prague, Czech Republic and 3Centre de Recherche des Cordeliers, Université Pierre et Marie Curie, Paris, France
*To whom correspondence should be addressed. Tel: +420 541517183; Fax: +420 541211293; Email: stros{at}ibp.cz Correspondence may also be addressed to François Strauss. Tel: +33 142346941; Fax: +33 142346893; Email: fstrauss{at}ccr.jussieu.fr
Received May 18, 2007. Revised June 21, 2007. Accepted June 22, 2007.
DNA topoisomerase II
(topo II) is an essential nuclear enzyme and its unique decatenation activity has been implicated in many aspects of chromosome dynamics such as chromosome replication and segregation during mitosis. Here we show that chromatin-associated protein HMGB1 (a member of the large family of HMG-box proteins with possible functions in DNA replication, transcription, recombination and DNA repair) promotes topo II-mediated catenation of circular DNA, relaxation of negatively supercoiled DNA and decatenation of kinetoplast DNA. HMGB1 interacts with topo II and this interaction, like the stimulation of the catalytic activity of the enzyme, requires both HMG-box domains of HMGB1. A mutant of HMGB1, which cannot change DNA topology stimulates DNA decatenation by topo II indistinguishably from the wild-type protein. Although HMGB1 stimulates ATP hydrolysis by topo II, the DNA cleavage is much more enhanced. The observed abilities of HMGB1 to interact with topo II and promote topo II binding to DNA suggest a mechanism by which HMGB1 stimulates the catalytic activity of the enzyme via enhancement of DNA cleavage.