title: Identification and partial characterization of a Mr 40,000 nucleolar antigen associated with cell proliferation.
abstract: The present study reports the identification and partial characterization of a novel Mr 40,000 nucleolar antigen (P40) by monoclonal antibodies. Monoclonal antibodies to this protein were obtained when a nucleolar protein extract separated from the immunodominant protein C23 was used to immunize BALB/c mice; 12 hybridoma clones produced antibodies to this protein. P40 was not detected in normal human kidney, liver, and leukocytes but was readily demonstrable in a variety of human malignant tissues. This newly identified P40 antigen differs in its specific nucleolar localization from cyclin (proliferating cell nuclear antigen), a Mr 35,000 antigen which is largely in the nucleoplasm. In addition, cyclin appears in the nucleolus in S-phase; P40 appears in the nucleolus 6 h after refeeding serum-starved HeLa cells.
mesh_terms: D000818:Animals; D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm / Q000032:analysis*; D006651:Histocytochemistry; D006801:Humans; D007399:Interphase; D007668:Kidney / Q000032:analysis; D015470:Leukemia, Myeloid, Acute / Q000473:pathology; D007962:Leukocytes / Q000032:analysis; D008099:Liver / Q000032:analysis; D051379:Mice; D008807:Mice, Inbred BALB C; D008858:Microscopy, Phase-Contrast; D008970:Molecular Weight; D009687:Nuclear Proteins; D000090243:Nucleophosmin; D009698:Nucleoproteins / Q000032:analysis*; D018809:Proliferating Cell Nuclear Antigen; D012261:Ribonucleoproteins / Q000032:analysis*
chemical_list: D000911:Antibodies, Monoclonal; D000951:Antigens, Neoplasm; D009687:Nuclear Proteins; D009698:Nucleoproteins; D018809:Proliferating Cell Nuclear Antigen; D012261:Ribonucleoproteins; C040391:malignancy-associated nucleolar antigen, human; D000090243:Nucleophosmin