jun-B inhibits and c-fos stimulates the transforming and trans-activating activities of c-jun.
We have cloned the human jun-B gene and determined its sequence and transforming and trans-activating activities. jun-B is less potent that c-jun in transforming and immortalizing primary rat embryo cells in cooperation with activated ras (effects enhanced by c-fos and TPA); unlike c-jun, jun-B does not transform Rat-1A cells alone. However, cotransfection of c-jun and jun-B into primary rat embryo cells with c-Ha-ras results in a significant decrease in transformation compared with c-jun alone, an event reversed by TPA. Cotransfection of c-jun and jun-B with or without c-fos into F9 teratocarcinoma cells results in decreased trans-activation of AP-1 compared with either gene alone. Introduction of jun-B into primary rat c-jun/ras transformants or c-jun into jun-B/ras transformants also results in a decrease in trans-activation. These findings demonstrate that, whereas jun-B and c-jun each participate in AP-1 trans-activation and malignant transformation, interactions between them involve negative regulation.
Schütte
J
J
NCI-Navy Medical Oncology Branch, Bethesda, Maryland.
Viallet
J
J
Nau
M
M
Segal
S
S
Fedorko
J
J
Minna
J
J
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002471:Cell Transformation, Neoplastic; D015342:DNA Probes; D004268:DNA-Binding Proteins / Q000235:genetics*; D005809:Genes, Regulator; D006801:Humans; D008969:Molecular Sequence Data; D009857:Oncogenes; D011505:Protein-Tyrosine Kinases / Q000235:genetics; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D011519:Proto-Oncogenes; D015347:RNA Probes; D051381:Rats; D015183:Restriction Mapping; D014157:Transcription Factors / Q000235:genetics*; D015533:Transcriptional Activation; D014162:Transfection
D015342:DNA Probes; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D015347:RNA Probes; D014157:Transcription Factors; D011505:Protein-Tyrosine Kinases