The product of a fos-related gene, fra-1, binds cooperatively to the AP-1 site with Jun: transcription factor AP-1 is comprised of multiple protein complexes.
fra-1 encodes a serum-inducible protein (Fra-1) that is antigenically related to Fos. We have characterized Fra-1 expression in serum-stimulated cells using antibodies raised against several regions of this protein. Fra-1, expressed transiently in COS cells or in serum-stimulated rat fibroblasts, undergoes extensive post-translational modification, primarily by phosphorylation of serine residues. It is present in both the nucleus and the cytoplasm and participates in a protein complex with Jun. Using proteins synthesized in reticulocyte lysates, we have shown that Fra-1, like Fos, binds to the AP-1 recognition element cooperatively with Jun. A truncated Fra-1 protein that contains the leucine zipper region but not an adjacent basic amino acid domain, complexes with Jun in vitro but fails to bind AP-1 oligonucleotides. These results demonstrate that Fra-1 contributes to the DNA-binding activity ascribed to transcription factor AP-1.
Cohen
D R
DR
Department of Molecular Oncology, Roche Research Center, Nutley, New Jersey 07110.
Ferreira
P C
PC
Gentz
R
R
Franza
B R
BR
Curran
T
T
D000818:Animals; D002478:Cells, Cultured; D055598:Chemical Phenomena; D002621:Chemistry; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004591:Electrophoresis, Polyacrylamide Gel; D005455:Fluorescent Antibody Technique; D010957:Plasmids; D011499:Protein Processing, Post-Translational; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D011519:Proto-Oncogenes; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D014162:Transfection
D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos; D016755:Proto-Oncogene Proteins c-jun; D014157:Transcription Factors