Abstract
Deregulated expression of c-myc can induce cell proliferation in established cell lines and in primary mouse embryonic fibroblasts (MEFs), through a combination of both transcriptional activation and repression by Myc. Here we show that a Myc-associated transcription factor, Miz-1, arrests cells in G1 phase and inhibits cyclin D-associated kinase activity. Miz-1 upregulates expression of the cyclin-dependent kinases (CDK) inhibitor p15INK4b by binding to the initiator element of the p15INK4b promoter. Myc and Max form a complex with Miz-1 at the p15 initiator and inhibit transcriptional activation by Miz-1. Expression of Myc in primary cells inhibits the accumulation of p15INK4b that is associated with cellular senescence; conversely, deletion of c-myc in an established cell line activates p15INK4b expression. Alleles of c-myc that are unable to bind to Miz-1 fail to inhibit accumulation of p15INK4b messenger RNA in primary cells and are, as a consequence, deficient in immortalization.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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3T3 Cells
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Animals
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Carrier Proteins / biosynthesis*
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Cell Cycle Proteins*
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Cyclin-Dependent Kinase Inhibitor p15
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Cyclin-Dependent Kinase Inhibitor p16*
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DNA-Binding Proteins / genetics
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DNA-Binding Proteins / metabolism*
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Gene Expression Regulation
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HeLa Cells
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Humans
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Kruppel-Like Transcription Factors
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Mice
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Nuclear Proteins / metabolism
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Promoter Regions, Genetic
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Proto-Oncogene Proteins c-myc / metabolism*
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Rats
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Recombinant Fusion Proteins / genetics
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Recombinant Fusion Proteins / metabolism
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Trans-Activators / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
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Tumor Suppressor Proteins*
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Zinc Fingers*
Substances
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CDKN2B protein, human
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Carrier Proteins
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Cdkn2b protein, mouse
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Cdkn2b protein, rat
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Cell Cycle Proteins
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Cyclin-Dependent Kinase Inhibitor p15
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Cyclin-Dependent Kinase Inhibitor p16
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DNA-Binding Proteins
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Kruppel-Like Transcription Factors
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Nuclear Proteins
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Proto-Oncogene Proteins c-myc
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Recombinant Fusion Proteins
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Trans-Activators
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Transcription Factors
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Tumor Suppressor Proteins
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ZBTB17 protein, human