Proto-oncogene fos: factors affecting expression and covalent modification of the gene product.
Expression of proto-oncogene fos is induced in response to a variety of growth factors and differentiation-specific agents. However, the induction of fos gene expression is not influenced by inhibition of protein synthesis. We, therefore, entertained the notion that expression of the fos gene may be governed by posttranslational modification of cellular transcriptional factors. We report here that transcription of the human c-fos gene is modulated by negatively and positively acting cellular factors. The nuclear protein products of the resident oncogene of the FBJ-murine osteosarcoma virus (v-fos) and its corresponding cellular proto-oncogene (c-fos) are stoichiometrically phosphorylated on serine and threonine residues. The c-fos protein is more highly phosphorylated than the v-fos protein due to the phosphorylation of unique sites tentatively localized to the c-terminal 20 amino acid residues. The protein kinase C agonist, TPA, stimulates phosphorylation of the c-fos, but not the v-fos protein.
Barber
J R
JR
Molecular Biology and Virology Laboratory, Salk Institute, San Diego, California 92138-9216.
Sassone-Corsi
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P
Verma
I M
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D000818:Animals; D001790:Blood Physiological Phenomena; D002417:Cattle; D002471:Cell Transformation, Neoplastic / Q000235:genetics; D002472:Cell Transformation, Viral; D002478:Cells, Cultured; D005347:Fibroblasts; D005786:Gene Expression Regulation / Q000187:drug effects; D015683:Gene Products, gag; D010766:Phosphorylation; D011494:Protein Kinases / Q000378:metabolism; D011499:Protein Processing, Post-Translational; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis* / Q000235:genetics; D016760:Proto-Oncogene Proteins c-fos; D011519:Proto-Oncogenes; D051381:Rats; D012191:Retroviridae Proteins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology; D009053:Sarcoma Viruses, Murine / Q000235:genetics / Q000502:physiology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects
D015683:Gene Products, gag; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D012191:Retroviridae Proteins; D011494:Protein Kinases; D013755:Tetradecanoylphorbol Acetate