title: A transcriptional repressor of c-myc.
abstract: In murine plasmacytomas there is deregulated transcription of a translocated c-myc allele and undetectable transcription of the normal, unrearranged c-myc allele. Deregulated c-myc transcription probably contributes to the transformed phenotype of the tumour cells, whereas repression of the normal allele probably reflects the normal turn-off of c-myc in non-dividing plasma cells. We previously identified a plasmacytoma-specific protein which binds to the c-myc promoter region 290 base pairs 5' of the P1 transcription start site. This plasmacytoma repressor factor (myc-PRF; formerly myc-PCF) is not found in cell lines representing earlier B-cell stages during which c-myc is transcribed, so it could be a negative regulator of c-myc transcription in terminally differentiated B cells. Here we report that site-directed deletion of the binding site for this protein leads to a 30-fold increase in transcription of a stably transfected c-myc fusion construct in plasmacytoma cells but has no effect in L cells or 18-81 pre-B cells, which lack the protein. Myc-PRF interacts with another widely distributed protein, myc-CF1 (common factor 1), which binds nearby, and this association may be important in myc-PRF repression.
authors.affiliation: Department of Biological Chemistry, UCLA School of Medicine 90024.
authors.forename: E
authors.initials: E
authors.lastname: Kakkis
authors.forename: K J
authors.initials: KJ
authors.lastname: Riggs
authors.forename: W
authors.initials: W
authors.lastname: Gillespie
authors.forename: K
authors.initials: K
authors.lastname: Calame
mesh_terms: D000818:Animals; D001483:Base Sequence; D002460:Cell Line; D006801:Humans; D007739:L Cells / Q000378:metabolism; D008969:Molecular Sequence Data; D010954:Plasmacytoma; D011518:Proto-Oncogene Proteins / Q000235:genetics; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes; D012097:Repressor Proteins / Q000378:metabolism*; D015183:Restriction Mapping; D014157:Transcription Factors / Q000378:metabolism*; D014158:Transcription, Genetic; D014162:Transfection
chemical_list: D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc; D012097:Repressor Proteins; D014157:Transcription Factors