title: An alternative spliced form of FosB is a negative regulator of transcriptional activation and transformation by Fos proteins.
abstract: Two forms of FosB transcript and their products can be identified in mouse NIH 3T3 cells following serum induction. The larger RNA codes for a 338-amino acid protein, whereas the smaller RNA results from the removal of an additional 140 nucleotides from FosB mRNA by alternative splicing. This alternative splicing event places a stop codon following the "leucine zipper" region and results in a shorter protein (FosB2) of 237 amino acids that lacks 101 amino acids at the carboxyl terminus. FosB2 is able to form heterodimers with c-Jun and bind to an AP-1 site but is not able to activate the transcription of promoters containing AP-1 sites. Furthermore, FosB2 can not only suppress the transcriptional activation by c-Fos and c-Jun of promoters containing an AP-1 site but also interferes with the transforming potential of viral and cellular Fos proteins. We propose that FosB2 protein functions as a trans-negative regulator.
authors.affiliation: Molecular Biology and Virology Laboratory, Salk Institute, San Diego, CA 92186-5800.
authors.forename: J
authors.initials: J
authors.lastname: Yen
authors.forename: R M
authors.initials: RM
authors.lastname: Wisdom
authors.forename: I
authors.initials: I
authors.lastname: Tratner
authors.forename: I M
authors.initials: IM
authors.lastname: Verma
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D001665:Binding Sites; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D016350:Leucine Zippers / Q000235:genetics; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids; D011233:Precipitin Tests; D011401:Promoter Regions, Genetic; D014176:Protein Biosynthesis; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics* / Q000378:metabolism; D016760:Proto-Oncogene Proteins c-fos; D012326:RNA Splicing; D014158:Transcription, Genetic; D015533:Transcriptional Activation
chemical_list: D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D011518:Proto-Oncogene Proteins; D016760:Proto-Oncogene Proteins c-fos