Abstract
JunD is the most broadly expressed member of the Jun family and the AP-1 transcription factor complex. Primary fibroblasts lacking JunD displayed p53-dependent growth arrest, upregulated p19(Arf) expression, and premature senescence. In contrast, immortalized cell lines lacking JunD showed increased proliferation and higher cyclinD1 levels. These properties are reminiscent of the effects of oncogenic Ras expression on primary and established cell cultures. Furthermore, JunD(-/-) fibroblasts exhibited increased p53-dependent apoptosis upon ultraviolet irradiation and were sensitive to the cytotoxic effects of TNF-alpha. The antiapoptotic role of JunD was confirmed using an in vivo model of TNF-mediated hepatitis. We propose that JunD protects cells from senescence, or apoptotic responses to stress stimuli, by acting as a modulator of the signaling pathways that link Ras to p53.
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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Apoptosis / drug effects
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Apoptosis / physiology*
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Apoptosis / radiation effects
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Cell Division / drug effects
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Cell Line, Transformed
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Cells, Cultured
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Cellular Senescence / drug effects
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Cellular Senescence / physiology*
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Cyclin D1 / metabolism
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Cyclin-Dependent Kinase Inhibitor p16
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Fibroblasts / cytology
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Fibroblasts / drug effects
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Fibroblasts / metabolism
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Fibroblasts / radiation effects
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Gene Deletion
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Hepatitis, Animal / chemically induced
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Hepatitis, Animal / metabolism
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Hepatitis, Animal / pathology
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Hepatocytes / drug effects
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Hepatocytes / metabolism
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Hepatocytes / pathology
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Lipopolysaccharides / pharmacology
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Mice
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Mice, Knockout
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Proto-Oncogene Proteins c-jun / deficiency
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Proto-Oncogene Proteins c-jun / genetics
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Proto-Oncogene Proteins c-jun / metabolism*
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Radiation Tolerance / genetics
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Signal Transduction / drug effects
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Signal Transduction / radiation effects
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Survival Rate
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Tumor Necrosis Factor-alpha / pharmacology
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Tumor Suppressor Protein p14ARF / metabolism
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Tumor Suppressor Protein p53 / antagonists & inhibitors*
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Tumor Suppressor Protein p53 / metabolism*
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Ultraviolet Rays
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ras Proteins / metabolism
Substances
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Cdkn2a protein, mouse
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Cyclin-Dependent Kinase Inhibitor p16
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Lipopolysaccharides
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Proto-Oncogene Proteins c-jun
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Tumor Necrosis Factor-alpha
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Tumor Suppressor Protein p14ARF
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Tumor Suppressor Protein p53
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Cyclin D1
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ras Proteins