Abstract
P21waf1/cip1 is a potent inhibitor of cell cycle progression and can inhibit the growth of both normal cells and cells transformed by a number of oncogenes. However, the ability of p21waf1/cip1 to inhibit the growth of cells that overexpress the transcriptional transactivator E2F1 is controversial: it has been reported both that E2F1 can and cannot overcome the block in the cell cycle induced by p21waf1/cip1. To avoid the complications that arise when such experiments are done with permanent cell lines, we tested the effects of overexpressing p21waf/cip1 and E2F1 in primary chicken embryo fibroblasts. In this system very high levels of E2F1 overexpression cause considerable apoptosis; however, the surviving cells still overexpress E2F1. These cells are transformed and their growth is blocked by overexpression of p21waf1/cip1.
Publication types
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Research Support, Non-U.S. Gov't
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Research Support, U.S. Gov't, P.H.S.
MeSH terms
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Animals
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Apoptosis / genetics
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Carrier Proteins*
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Cell Cycle Proteins*
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Cell Division / genetics*
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Cell Line, Transformed
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Chick Embryo
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclins / genetics*
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DNA-Binding Proteins*
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E2F Transcription Factors
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E2F1 Transcription Factor
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Fibroblasts / cytology
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Fibroblasts / metabolism
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G1 Phase / genetics
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Genetic Vectors
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Proto-Oncogene Proteins c-bcl-2 / metabolism
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Retinoblastoma-Binding Protein 1
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Retroviridae / genetics
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Transcription Factors / genetics*
Substances
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Carrier Proteins
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Cell Cycle Proteins
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Cyclin-Dependent Kinase Inhibitor p21
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Cyclins
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DNA-Binding Proteins
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E2F Transcription Factors
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E2F1 Transcription Factor
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Proto-Oncogene Proteins c-bcl-2
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Retinoblastoma-Binding Protein 1
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Transcription Factors