Abstract
One obvious phenotype of tumor cells is the lack of terminal differentiation. We previously classified rhabdomyosarcoma cell lines as having either a recessive or a dominant nondifferentiating phenotype. To study the genetic basis of the dominant nondifferentiating phenotype, we utilized microcell fusion to transfer chromosomes from rhabdomyosarcoma cells into C2C12 myoblasts. Transfer of a derivative chromosome 14 inhibits differentiation. The derivative chromosome 14 contains a DNA amplification. MDM2 is amplified and overexpressed in these nondifferentiating hybrids and in the parental rhabdomyosarcoma. Forced expression of MDM2 inhibits MyoD-dependent transcription. Expression of antisense MDM2 restores MyoD-dependent transcriptional activity. We conclude that amplification and overexpression of MDM2 inhibit MyoD function, resulting in a dominant nondifferentiating phenotype.
Publication types
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Research Support, Non-U.S. Gov't
MeSH terms
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Animals
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Cell Cycle
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Cell Differentiation
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Cell Fusion
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Chromosomes, Human, Pair 14 / genetics
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Epistasis, Genetic
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Gene Amplification*
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Gene Expression Regulation
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Humans
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Hybrid Cells / pathology*
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Mice
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Muscle Proteins / genetics
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Muscle Proteins / physiology*
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Muscles / cytology*
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MyoD Protein / antagonists & inhibitors*
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MyoD Protein / physiology
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Neoplasm Proteins / genetics
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Neoplasm Proteins / physiology*
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Nuclear Proteins*
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Phenotype
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Polymerase Chain Reaction
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Proto-Oncogene Proteins / genetics
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Proto-Oncogene Proteins / physiology*
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Proto-Oncogene Proteins c-mdm2
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Rhabdomyosarcoma / genetics*
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Rhabdomyosarcoma / pathology
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Transcription, Genetic
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Tumor Cells, Cultured
Substances
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Muscle Proteins
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MyoD Protein
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Neoplasm Proteins
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Nuclear Proteins
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Proto-Oncogene Proteins
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MDM2 protein, human
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Mdm2 protein, mouse
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Proto-Oncogene Proteins c-mdm2