v-jun encodes a nuclear protein with enhancer binding properties of AP-1.
The jun oncogene of ASV17 is expressed as a 65 kd protein (p65gag-jun) that contains partial gag sequences at its amino terminus fused to jun sequences that make up the carboxy terminal two-thirds of the molecule. As a first step toward evaluating potential functional differences between the activated oncogene, v-jun, and its cellular counterpart, c-jun, we have characterized the biochemical properties of the gag-jun product of ASV17. Immunofluorescence studies revealed that the v-jun protein is localized in the nucleus of CEF transfected with ASV17 DNA. DNAase I foot-printing analysis indicates that p65gag-jun synthesized in bacteria binds to enhancer elements in SV40 that are recognition sites for the human transcription factor AP-1. Analysis of point mutants confirmed that v-jun protein binds with DNA sequence specificity of the mammalian enhancer factor AP-1 and the yeast transcription factor GCN4. These findings suggest that activation of the jun oncogene may not exclusively be the result of alterations in the DNA binding properties of the normal cellular protein.
Bos
T J
TJ
Department of Microbiology, University of Southern California, School of Medicine, Los Angeles 90033.
Bohmann
D
D
Tsuchie
H
H
Tjian
R
R
Vogt
P K
PK
D017456:Adenovirus Early Proteins; D000818:Animals; D001358:Avian Sarcoma Viruses / Q000235:genetics*; D001483:Base Sequence; D001665:Binding Sites; D002467:Cell Nucleus / Q000378:metabolism; D002642:Chick Embryo; D004247:DNA / Q000378:metabolism; D004274:DNA, Recombinant; D004279:DNA, Viral / Q000235:genetics; D004268:DNA-Binding Proteins / Q000378:metabolism*; D004742:Enhancer Elements, Genetic; D005455:Fluorescent Antibody Technique; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D009856:Oncogene Proteins, Viral / Q000235:genetics*; D009857:Oncogenes; D016755:Proto-Oncogene Proteins c-jun; D013539:Simian virus 40 / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*; D014162:Transfection; D014764:Viral Proteins / Q000235:genetics* / Q000378:metabolism
D017456:Adenovirus Early Proteins; D004274:DNA, Recombinant; D004279:DNA, Viral; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D009856:Oncogene Proteins, Viral; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors; D014764:Viral Proteins; D004247:DNA