title: Identification of a rel-related protein in the nucleus during the S phase of the cell cycle.
abstract: The c-rel proto-oncogene encodes a 75-kDa protein (p75c-rel) which is present in the cytosol of chick embryo fibroblasts (CEF) associated with a distinct set of cellular proteins with molecular masses of 40, 115, and 124 kDa. CEF cultures arrested in S phase of the cell cycle, or enriched for G2 or mitotic cells, were examined to determine whether the expression of c-rel was altered during the cell cycle. Levels of p75c-rel remained constant in all portions of the cell cycle examined; however, a Rel-related protein with an apparent molecular mass of 64 kDa was detected in nuclei of S-phase cells. As cells enter G2, the level of this protein in the nucleus decreases. This protein reacts with antiserum generated against the carboxy terminus of p75c-rel in radioimmunoprecipitations and Western immunoblot experiments and was also detected in a Western immunoblot with antiserum generated against the first 161 amino acids of pp59v-rel. Thus, unlike other Rel/NF-kappa B family members, p64 has carboxy-terminal homology with c-Rel. The majority of peptides generated by partial proteolytic cleavage of p64 are shared with peptides generated by digestion of p75c-rel and/or pp59v-rel. We suggest that this protein represents a new member of the Rel family of transcription factors and is located in the nucleus of avian fibroblasts during S phase of the cell cycle.
authors.affiliation: Department of Microbiology, University of Texas, Austin 78712.
authors.forename: R B
authors.initials: RB
authors.lastname: Evans
authors.forename: P D
authors.initials: PD
authors.lastname: Gottlieb
authors.forename: H R
authors.initials: HR
authors.lastname: Bose
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D015153:Blotting, Western; D002467:Cell Nucleus / Q000737:chemistry*; D002478:Cells, Cultured; D002642:Chick Embryo; D005347:Fibroblasts / Q000737:chemistry / Q000166:cytology; D008969:Molecular Sequence Data; D020572:Oncogene Proteins v-rel; D010446:Peptide Fragments / Q000737:chemistry; D011518:Proto-Oncogene Proteins / Q000032:analysis*; D020569:Proto-Oncogene Proteins c-rel; D015531:Radioimmunoprecipitation Assay; D015682:Retroviridae Proteins, Oncogenic / Q000737:chemistry; D016196:S Phase; D017386:Sequence Homology, Amino Acid; D051841:Transcription Factor RelB; D014157:Transcription Factors
chemical_list: D020572:Oncogene Proteins v-rel; D010446:Peptide Fragments; D011518:Proto-Oncogene Proteins; D020569:Proto-Oncogene Proteins c-rel; D015682:Retroviridae Proteins, Oncogenic; D014157:Transcription Factors; D051841:Transcription Factor RelB