Abstract
Overexpression of cyclin E, an activator of cyclin-dependent kinase 2, has been linked to human cancer. In cell culture models, the forced expression of cyclin E leads to aneuploidy and polyploidy, which is consistent with a direct role of cyclin E overexpression in tumorigenesis. In this study, we show that the overexpression of cyclin E has a direct effect on progression through the latter stages of mitotic prometaphase before the complete alignment of chromosomes at the metaphase plate. In some cases, such cells fail to divide chromosomes, resulting in polyploidy. In others, cells proceed to anaphase without the complete alignment of chromosomes. These phenotypes can be explained by an ability of overexpressed cyclin E to inhibit residual anaphase-promoting complex (APC(Cdh1)) activity that persists as cells progress up to and through the early stages of mitosis, resulting in the abnormal accumulation of APC(Cdh1) substrates as cells enter mitosis. We further show that the accumulation of securin and cyclin B1 can account for the cyclin E-mediated mitotic phenotype.
Publication types
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Research Support, N.I.H., Extramural
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Research Support, U.S. Gov't, Non-P.H.S.
MeSH terms
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Anaphase-Promoting Complex-Cyclosome
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Animals
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Cell Cycle / physiology*
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Cell Line
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Cyclin A / metabolism
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Cyclin B / genetics
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Cyclin B / metabolism
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Cyclin B1
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Cyclin E / genetics
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Cyclin E / metabolism*
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Cyclin-Dependent Kinase 2 / genetics
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Cyclin-Dependent Kinase 2 / metabolism
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Humans
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Microscopy, Fluorescence / methods
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Mitosis / physiology*
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Neoplasm Proteins / genetics
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Neoplasm Proteins / metabolism
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RNA, Small Interfering / metabolism
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Securin
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Ubiquitin / metabolism
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Ubiquitin-Protein Ligase Complexes / antagonists & inhibitors*
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Ubiquitin-Protein Ligase Complexes / genetics
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Ubiquitin-Protein Ligase Complexes / metabolism*
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Ubiquitin-Protein Ligases / metabolism
Substances
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CCNB1 protein, human
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Cyclin A
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Cyclin B
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Cyclin B1
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Cyclin E
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Neoplasm Proteins
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RNA, Small Interfering
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Recombinant Fusion Proteins
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Securin
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Ubiquitin
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pituitary tumor-transforming protein 1, human
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Ubiquitin-Protein Ligase Complexes
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Anaphase-Promoting Complex-Cyclosome
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Ubiquitin-Protein Ligases
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CDK2 protein, human
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Cyclin-Dependent Kinase 2