The bZIP domains of Fos and Jun mediate a physical association with the TATA box-binding protein.
Fos and Jun oncoproteins form a complex that regulates transcription from promoters containing AP-1 binding sites. These two proteins, like other transcriptional activators, are likely to stimulate transcription through direct and/or indirect interactions with members of the basal transcriptional machinery. The ability of c-Fos and c-Jun proteins to interact directly with the TATA box-binding protein (TBP), the general transcription factor required for initiating the assembly of transcription complexes, was investigated. Using co-immunoprecipitation and protein-protein association assays, we show that both c-Fos and c-Jun bind specifically and stably to TBP. Mutational analysis demonstrates that both the basic region and leucine zipper domains of c-Fos and c-Jun are necessary and sufficient for stable association with TBP. A 51-residue region from the conserved C-terminal region of TBP, previously shown to be the binding site for the viral activator protein E1A, interacts with c-Fos and c-Jun proteins. We propose that c-Fos and c-Jun proteins function as transcriptional activators, in part by recruiting TBP to form complexes to initiate RNA synthesis.
Ransone
L J
LJ
Molecular Biology and Virology Laboratory, Salk Institute, San Diego, CA 85800.
Kerr
L D
LD
Schmitt
M J
MJ
Wamsley
P
P
Verma
I M
IM
D000595:Amino Acid Sequence; D001665:Binding Sites; D004268:DNA-Binding Proteins / Q000378:metabolism*; D006801:Humans; D016350:Leucine Zippers / Q000235:genetics / Q000502:physiology; D008969:Molecular Sequence Data; D017354:Point Mutation; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics / Q000378:metabolism*; D016755:Proto-Oncogene Proteins c-jun / Q000235:genetics / Q000378:metabolism*; D012313:RNA / Q000096:biosynthesis; D016385:TATA Box; D035181:TATA-Box Binding Protein; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D035181:TATA-Box Binding Protein; D014157:Transcription Factors; D012313:RNA