DNA topoisomerase (topo) II catalyses topological genomic changes essential for many DNA metabolic processes. It is also regarded as a structural component of the nuclear matrix in interphase and the mitotic chromosome scaffold. Mammals have two isoforms (α and β) with similar properties in vitro. Here, we investigated their properties in living and proliferating cells, stably expressing biofluorescent chimera of the human isozymes. Topo IIα and IIβ behaved similarly in interphase but differently in mitosis, where only topo IIα was chromosome associated to a major part. During interphase, both isozymes joined in nucleolar reassembly and accumulated in nucleoli, which seemed not to involve catalytic DNA turnover because treatment with teniposide (stabilizing covalent catalytic DNA intermediates of topo II) relocated the bulk of the enzymes from the nucleoli to nucleoplasmic granules. Photobleaching revealed that the entire complement of both isozymes was completely mobile and free to exchange between nuclear subcompartments in interphase. In chromosomes, topo IIα was also completely mobile and had a uniform distribution. However, hypotonic cell lysis triggered an axial pattern. These observations suggest that topo II is not an immobile, structural component of the chromosomal scaffold or the interphase karyoskeleton, but rather a dynamic interaction partner of such structures.
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1 April 2002
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April 01 2002
Dynamics of human DNA topoisomerases IIα and IIβ in living cells
Morten O. Christensen,
Morten O. Christensen
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
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Morten K. Larsen,
Morten K. Larsen
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
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Hans Ullrich Barthelmes,
Hans Ullrich Barthelmes
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
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Robert Hock,
Robert Hock
4Department of Cell and Developmental Biology, Biocenter, University of Würzburg, D-97074 Würzburg, Germany
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Claus L. Andersen,
Claus L. Andersen
5Cancercytogenetics Laboratory, Aarhus Amtssygehus, Aarhus University Hospital, DK-8000 Aarhus C, Denmark
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Eigil Kjeldsen,
Eigil Kjeldsen
3Department of Clincal Genetics, University of Aarhus, DK-8200 Aarhus-C, Denmark
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Birgitta R. Knudsen,
Birgitta R. Knudsen
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
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Ole Westergaard,
Ole Westergaard
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
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Fritz Boege,
Fritz Boege
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
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Christian Mielke
Christian Mielke
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
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Morten O. Christensen
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
Morten K. Larsen
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
Hans Ullrich Barthelmes
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
Robert Hock
4Department of Cell and Developmental Biology, Biocenter, University of Würzburg, D-97074 Würzburg, Germany
Claus L. Andersen
5Cancercytogenetics Laboratory, Aarhus Amtssygehus, Aarhus University Hospital, DK-8000 Aarhus C, Denmark
Eigil Kjeldsen
3Department of Clincal Genetics, University of Aarhus, DK-8200 Aarhus-C, Denmark
Birgitta R. Knudsen
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
Ole Westergaard
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
Fritz Boege
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
Christian Mielke
1Department of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, D-97070 Würzburg, Germany
2Department of Molecular and Structural Biology, University of Aarhus, DK-8200 Aarhus-C, Denmark
Address correspondence to Christian Mielke, Dept. of Clinical Chemistry, Medizinische Poliklinik, University of Würzburg, Klinikstrasse 6-8, D-97070 Würzburg, Germany. Tel.: 49-931-201-7008. Fax: 49-931-201-7098. E-mail: [email protected]
The online version of this article contains supplemental material.
*
Abbreviations used in this paper: FLIP, fluorescence loss in photobleaching; FOA, fluoroorotic acid; GFP, green fluorescent protein; topo, DNA topoisomerase; TPI, triose phosphate isomerase.
Received:
December 06 2001
Revision Received:
February 20 2002
Accepted:
February 21 2002
Online ISSN: 1540-8140
Print ISSN: 0021-9525
The Rockefeller University Press
2002
J Cell Biol (2002) 157 (1): 31–44.
Article history
Received:
December 06 2001
Revision Received:
February 20 2002
Accepted:
February 21 2002
Citation
Morten O. Christensen, Morten K. Larsen, Hans Ullrich Barthelmes, Robert Hock, Claus L. Andersen, Eigil Kjeldsen, Birgitta R. Knudsen, Ole Westergaard, Fritz Boege, Christian Mielke; Dynamics of human DNA topoisomerases IIα and IIβ in living cells . J Cell Biol 1 April 2002; 157 (1): 31–44. doi: https://doi.org/10.1083/jcb.200112023
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