title: Multiple growth-associated nuclear proteins immunoprecipitated by antisera raised against human c-myc peptide antigens.
abstract: Different antisera raised against various regions of the human c-myc protein were used to identify four human c-myc proteins with apparent molecular masses in sodium dodecyl sulfate-polyacrylamide gels ranging from 64 to 68 kilodaltons (phosphoproteins pp64 and pp67 and nonphosphorylated proteins p65 and p68). pp64 and p65 were the major detectable c-myc proteins, and pp67 and p68 were minor but specific components of the immunoprecipitates. The c-myc proteins were all localized in the cell nucleus. Accumulation of [35S]methionine-labeled p65 was observed after pulse-labeling and chase, suggesting that the stable p65 c-myc protein is generated posttranslationally from short-lived precursors. pp64, pp67, and p68 possessed short half-lives and may therefore be precursors of the stable p65. Confirmation of the nuclear localization of the human c-myc proteins was obtained by immunofluorescent staining. The human c-myc proteins were revealed as a pattern of punctate nuclear staining with, particularly for p65, nucleolar enhancement that left an unstained annulus surrounding the nucleolus.
mesh_terms: D000951:Antigens, Neoplasm / Q000235:genetics*; D002460:Cell Line; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells / Q000166:cytology; D006801:Humans; D007106:Immune Sera; D007700:Kinetics; D015470:Leukemia, Myeloid, Acute; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000235:genetics*; D016271:Proto-Oncogene Proteins c-myc; D011519:Proto-Oncogenes
chemical_list: D000951:Antigens, Neoplasm; D007106:Immune Sera; D011518:Proto-Oncogene Proteins; D016271:Proto-Oncogene Proteins c-myc