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We have investigated the role of topoisomerase II (topo II) in mitotic chromosome assembly and organization in vitro using Xenopus egg extracts. When sperm chromatin was incubated with mitotic extracts, the highly compact chromatin rapidly swelled and concomitantly underwent local condensation. Further incubation induced the formation of entangled thin chromatin fibers that eventually resolved into highly condensed individual chromosomes. This in vitro system made it possible to manipulate mitotic chromosomes in their assembly condition without any isolation or stabilization steps. Two complementary approaches, immunodepletion and antibody blocking, demonstrated that topo II activity is required for chromosome assembly and condensation. Once condensation was completed, however, blocking of topo II activity had little effect on the chromosome morphology. Immunofluorescent studies showed that topo II was uniformly distributed throughout the condensed chromosomes and was not restricted to the chromosomal axis. Surprisingly, all detectable topo II molecules were easily extracted from the chromosomes under mild conditions where the shape of chromosomes was well preserved. Our results show that topo II is essential for mitotic chromosome assembly, but does not play a scaffolding role in the structural maintenance of chromosomes assembled in vitro. We also present evidence that changes of DNA topology affect the distribution of topo II in mitotic chromosomes in our system.
Adachi,
Chromosome assembly in vitro: topoisomerase II is required for condensation.
1991, Pubmed,
Xenbase
Adachi,
Chromosome assembly in vitro: topoisomerase II is required for condensation.
1991,
Pubmed
,
Xenbase
Almouzni,
Assembly of spaced chromatin involvement of ATP and DNA topoisomerase activity.
1988,
Pubmed
,
Xenbase
Benedetti,
Purification and characterization of Xenopus laevis topoisomerase II.
1983,
Pubmed
,
Xenbase
Blow,
Initiation of DNA replication in nuclei and purified DNA by a cell-free extract of Xenopus eggs.
1986,
Pubmed
,
Xenbase
Chen,
Nonintercalative antitumor drugs interfere with the breakage-reunion reaction of mammalian DNA topoisomerase II.
1984,
Pubmed
Chung,
Characterization and immunological identification of cDNA clones encoding two human DNA topoisomerase II isozymes.
1989,
Pubmed
Compton,
Identification of novel centromere/kinetochore-associated proteins using monoclonal antibodies generated against human mitotic chromosome scaffolds.
1991,
Pubmed
Compton,
Primary structure of NuMA, an intranuclear protein that defines a novel pathway for segregation of proteins at mitosis.
1992,
Pubmed
Davis,
Monoclonal antibodies to mitotic cells.
1983,
Pubmed
,
Xenbase
Drake,
Biochemical and pharmacological properties of p170 and p180 forms of topoisomerase II.
1989,
Pubmed
Earnshaw,
Localization of topoisomerase II in mitotic chromosomes.
1985,
Pubmed
Earnshaw,
Topoisomerase II is a structural component of mitotic chromosome scaffolds.
1985,
Pubmed
Earnshaw,
Analysis of the distribution of the INCENPs throughout mitosis reveals the existence of a pathway of structural changes in the chromosomes during metaphase and early events in cleavage furrow formation.
1991,
Pubmed
Gasser,
Studies on scaffold attachment sites and their relation to genome function.
1989,
Pubmed
Gasser,
Metaphase chromosome structure. Involvement of topoisomerase II.
1986,
Pubmed
Giaever,
The complete nucleotide sequence of the structural gene TOP2 of yeast DNA topoisomerase II.
1986,
Pubmed
Gurdon,
Injected nuclei in frog oocytes: fate, enlargement, and chromatin dispersal.
1976,
Pubmed
,
Xenbase
Hadlaczky,
Protein-depleted chromosomes. II. Experiments concerning the reality of chromosome scaffolds.
1981,
Pubmed
Hirano,
Cell cycle control of higher-order chromatin assembly around naked DNA in vitro.
1991,
Pubmed
,
Xenbase
Hiraoka,
Focal points for chromosome condensation and decondensation revealed by three-dimensional in vivo time-lapse microscopy.
1989,
Pubmed
Laskey,
Assembly of the cell nucleus.
1990,
Pubmed
Lewis,
Higher order metaphase chromosome structure: evidence for metalloprotein interactions.
1982,
Pubmed
Lohka,
Effects of Ca2+ ions on the formation of metaphase chromosomes and sperm pronuclei in cell-free preparations from unactivated Rana pipiens eggs.
1984,
Pubmed
,
Xenbase
Lohka,
Formation in vitro of sperm pronuclei and mitotic chromosomes induced by amphibian ooplasmic components.
1983,
Pubmed
,
Xenbase
Luke,
Quantitation of type II topoisomerase in oocytes and eggs of Xenopus laevis.
1989,
Pubmed
,
Xenbase
Marini,
Decatenation of kinetoplast DNA by topoisomerases.
1980,
Pubmed
Murray,
The role of cyclin synthesis and degradation in the control of maturation promoting factor activity.
1989,
Pubmed
,
Xenbase
Newmeyer,
Assembly in vitro of nuclei active in nuclear protein transport: ATP is required for nucleoplasmin accumulation.
1986,
Pubmed
,
Xenbase
Newport,
Nuclear reconstitution in vitro: stages of assembly around protein-free DNA.
1987,
Pubmed
,
Xenbase
Newport,
Disassembly of the nucleus in mitotic extracts: membrane vesicularization, lamin disassembly, and chromosome condensation are independent processes.
1987,
Pubmed
,
Xenbase
Okada,
A search for protein cores in chromosomes: is the scaffold an artifact?
1980,
Pubmed
Paulson,
The structure of histone-depleted metaphase chromosomes.
1977,
Pubmed
Paulson,
Scaffold morphology in histone-depleted HeLa metaphase chromosomes.
1989,
Pubmed
Rieder,
Colcemid and the mitotic cycle.
1992,
Pubmed
Sawin,
Mitotic spindle assembly by two different pathways in vitro.
1991,
Pubmed
,
Xenbase
Shelton,
DNA topoisomerase II from Drosophila melanogaster. Purification and physical characterization.
1983,
Pubmed
Studier,
Use of T7 RNA polymerase to direct expression of cloned genes.
1990,
Pubmed
Tsai-Pflugfelder,
Cloning and sequencing of cDNA encoding human DNA topoisomerase II and localization of the gene to chromosome region 17q21-22.
1988,
Pubmed
Tymowska,
Karyotype analysis of Xenopus muelleri (Peters) and Xenopus laevis (Daudin), Pipidae.
1972,
Pubmed
,
Xenbase
Uemura,
The nucleotide sequence of the fission yeast DNA topoisomerase II gene: structural and functional relationships to other DNA topoisomerases.
1986,
Pubmed
Uemura,
DNA topoisomerase II is required for condensation and separation of mitotic chromosomes in S. pombe.
1987,
Pubmed
Woessner,
Proliferation- and cell cycle-dependent differences in expression of the 170 kilodalton and 180 kilodalton forms of topoisomerase II in NIH-3T3 cells.
1991,
Pubmed
Wood,
Mitotic chromatin condensation in vitro using somatic cell extracts and nuclei with variable levels of endogenous topoisomerase II.
1990,
Pubmed
Wyckoff,
Structure of the Drosophila DNA topoisomerase II gene. Nucleotide sequence and homology among topoisomerases II.
1989,
Pubmed
Zechiedrich,
Eukaryotic topoisomerases recognize nucleic acid topology by preferentially interacting with DNA crossovers.
1990,
Pubmed
