CROC-1 encodes a protein which mediates transcriptional activation of the human FOS promoter.
The cloning of signal transducing molecules capable of activating the human FOS proto-oncogene promoter was achieved by co-transfecting a modified human FOS promoter-driven polyomavirus large T antigen gene (P(f)LAG-8) with a human brain cDNA library, incorporated into a replication-competent mammalian retroviral expression vector whose replication occurs in the presence of T antigen. In murine cells, transcriptional activation of the P(f)LAG-8 promoter by a biologically active, cDNA-encoded signalling molecule resulted in plasmid replication. Replicated plasmids, following selective cleavage of unreplicated plasmids by Dpn1, were recovered by transformation into competent bacteria. Successive P(f)LAG-8/cDNA library co-transfections, using library plasmids resulting from prior transfections, ultimately resulted in the identification of individual plasmids capable of transcriptionally activating the FOS promoter. DNA sequencing revealed the first plasmid, denoted CROC-1, to contain a 1.8-kb cDNA encoding a 16.5-kDa nuclear protein possessing a bipartite structure comprised an amino-terminal acidic domain and a carboxy-terminal basic domain, and displaying partial homology to the HMG domain of the TAF(II)250 transcription cofactor. Co-transfection of CROC-1 with various FOS/CAT reporter genes revealed that the human FOS promoter region spanning -56 to - 105, encompassing two identical 8-bp DR enhancer sequences, was necessary for CROC-1-mediated transcriptional activation. Results suggest that CROC-1 participates in intracellular signalling pathways involved in induction of the human FOS promoter.
Rothofsky
M L
ML
Department of Tumor Biology, The Schering-Plough Research Institute, Kenilworth, NJ 07033, USA.
Lin
S L
SL
D016475:3T3 Cells; D000595:Amino Acid Sequence; D000818:Animals; D000957:Antigens, Viral, Tumor / Q000235:genetics; D001483:Base Sequence; D002478:Cells, Cultured; D015723:Gene Library; D017930:Genes, Reporter; D016762:Genes, fos; D005822:Genetic Vectors; D006801:Humans; D051379:Mice; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000235:genetics* / Q000378:metabolism; D010957:Plasmids / Q000235:genetics*; D011120:Polyomavirus / Q000235:genetics; D011401:Promoter Regions, Genetic; D000090063:Proto-Oncogene Mas; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics*; D051381:Rats; D012091:Repetitive Sequences, Nucleic Acid; D017422:Sequence Analysis, DNA; D015398:Signal Transduction / Q000235:genetics*; D015534:Trans-Activators / Q000235:genetics* / Q000378:metabolism; D014157:Transcription Factors; D015533:Transcriptional Activation; D014170:Transformation, Genetic; D044763:Ubiquitin-Conjugating Enzymes
D000957:Antigens, Viral, Tumor; C000715470:MAS1 protein, human; D009687:Nuclear Proteins; D000090063:Proto-Oncogene Mas; D016760:Proto-Oncogene Proteins c-fos; D015534:Trans-Activators; D014157:Transcription Factors; C471624:UBE2V1 protein, human; D044763:Ubiquitin-Conjugating Enzymes