Abstract
Condensin, a major non-histone protein complex on chromosomes, is responsible for the formation of rod-shaped chromosome in mitosis. A heterodimer composed of SMC2 (structural maintenance of chromosomes) and SMC4 subunits constitutes the core part of condensin. Although extensive studies have been done in yeast, fruit fly and Xenopus to uncover the mechanisms and molecular nature of SMC proteins, little is known about the complex in mammalian cells. We have conducted a series of experiments to unveil the nature of condensin complex in human chromosome formation. The results show that overexpression of the C-terminal domain of SMC subunits disturbs chromosome condensation, leading to formation of swollen chromosomes, while knockdown of SMC subunits severely disturbs mitotic chromosome formation, resulting in chromatin bridges between daughter cells and multiple nuclei in single cells. The salt extraction assay indicates that a fraction of the condensin complex is bound to chromatin in interphase, but most of the condensin bind to chromatin at the onset of mitosis. Thus, disturbance in condensin function or expression affects chromosome condensation and influences mitotic progression.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Adenosine Triphosphatases / chemistry
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Adenosine Triphosphatases / genetics
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Adenosine Triphosphatases / metabolism*
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Animals
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Carrier Proteins / genetics
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Carrier Proteins / metabolism*
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Cell Cycle Proteins
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Chromatin / chemistry
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Chromatin / genetics
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Chromatin / metabolism*
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Chromosomes / chemistry
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Chromosomes / genetics
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Chromosomes / metabolism*
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DNA-Binding Proteins / chemistry
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Drosophila
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Female
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Fluorescent Antibody Technique
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Gene Expression
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Gene Silencing / drug effects
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HeLa Cells
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Humans
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Mitosis
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Multiprotein Complexes / chemistry
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Multiprotein Complexes / genetics
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Multiprotein Complexes / metabolism*
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism*
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Plasmids
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Protein Structure, Tertiary
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Protein Subunits / genetics
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Protein Subunits / metabolism*
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RNA, Small Interfering / pharmacology
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Recombinant Proteins / chemistry
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Recombinant Proteins / genetics
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Recombinant Proteins / metabolism*
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Saccharomyces cerevisiae
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Transfection
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Xenopus
Substances
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Carrier Proteins
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Cell Cycle Proteins
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Chromatin
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DNA-Binding Proteins
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Multiprotein Complexes
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Nuclear Proteins
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Protein Subunits
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RNA, Small Interfering
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Recombinant Proteins
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SMC2 protein, human
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condensin complexes
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Adenosine Triphosphatases