title: p105, the NF-kappa B p50 precursor protein, is one of the cellular proteins complexed with the v-Rel oncoprotein in transformed chicken spleen cells.
abstract: Active NF-kappa B-like transcription complexes are multimers consisting of one or two members of a family of proteins related to the c-Rel proto-oncoprotein. We have isolated a chicken cDNA encoding p105, the precursor protein for the p50 subunit of NF-kappa B. Sequence analysis shows that chicken p105 is approximately 70% identical to the mouse and human p105 proteins, containing the Rel homology domain in its N-terminal 370 amino acids and several ankyrinlike repeats in the C-terminal portion of the protein. The Rel homology domain is particularly highly conserved between chicken and mammalian p50, and an in vitro-synthesized, truncated chicken p105 protein, containing sequences that correspond to the predicted p50 protein, bound to a consensus kappa B site in an electrophoretic mobility shift assay. In v-Rel-transformed chicken spleen cells, v-Rel is found in high-molecular-weight complexes which include cellular proteins of approximately 124 kDa (p124) and 115 kDa (p115). Here we report that in vitro-produced p105 comigrates with p124 from v-Rel-transformed spleen cells and that p105 and p124 appear to be identical by partial proteolytic mapping with V8 protease. Furthermore, both p105 and p50 can complex directly with v-Rel and chicken c-Rel in vitro. However, in vitro association with p105 by v-Rel does not necessarily correlate with transformation, since one nontransforming v-Rel mutant can associate with p105 in vitro.
authors.affiliation: Department of Biology, Boston University, Massachusetts 02215.
authors.forename: A J
authors.initials: AJ
authors.lastname: Capobianco
authors.forename: D
authors.initials: D
authors.lastname: Chang
authors.forename: G
authors.initials: G
authors.lastname: Mosialos
authors.forename: T D
authors.initials: TD
authors.lastname: Gilmore
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002461:Cell Line, Transformed; D002645:Chickens; D003001:Cloning, Molecular; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000235:genetics*; D052002:NF-kappa B p50 Subunit; D015513:Oncogene Proteins / Q000378:metabolism*; D011498:Protein Precursors / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid; D013154:Spleen / Q000473:pathology
chemical_list: D016328:NF-kappa B; D052002:NF-kappa B p50 Subunit; D015513:Oncogene Proteins; D011498:Protein Precursors