title: Immunolocalization and partial characterization of a nucleolar autoantigen (PM-Scl) associated with polymyositis/scleroderma overlap syndromes.
abstract: Precipitating anti-PM-Scl antibodies are present in sera from patients with polymyositis, scleroderma, and polymyositis/scleroderma overlap syndromes. By indirect immunofluorescence microscopy, anti-PM-Scl antibodies stained the nucleolus in cells of different tissues and species, suggesting that the antigen is highly conserved. By electron microscopy, anti-PM-Scl antibodies reacted primarily with the granular component of the nucleolus. Drugs that inhibit rRNA synthesis had a marked effect on the expression of PM-Scl antigen. In actinomycin D-treated cells, immunofluorescence staining by anti-PM-Scl was significantly reduced with residual staining restricted to the granular regions of nucleoli. Treatment with 5,6-dichloro-beta-D-ribofuranosylbenzimidazole (DRB) also selectively reduced nucleolar staining. On a molecular level, anti-PM-Scl antibodies precipitated 11 polypeptides with molecular weights (Mr) ranging from 110,000 to 20,000. The Mr 80,000 and 20,000 polypeptides were phosphorylated. Evidence suggests that the PM-Scl antigen complex may be related to a preribosomal particle.
mesh_terms: D000818:Animals; D034961:Antigens, Nuclear; D001323:Autoantibodies / Q000276:immunology*; D001324:Autoantigens / Q000032:analysis / Q000276:immunology*; D002453:Cell Cycle; D002466:Cell Nucleolus / Q000276:immunology* / Q000648:ultrastructure; D003609:Dactinomycin / Q000494:pharmacology; D004004:Dichlororibofuranosylbenzimidazole / Q000494:pharmacology; D005455:Fluorescent Antibody Technique; D006367:HeLa Cells / Q000032:analysis; D006801:Humans; D009220:Myositis / Q000276:immunology*; D009698:Nucleoproteins / Q000032:analysis* / Q000276:immunology; D012595:Scleroderma, Systemic / Q000276:immunology*; D014709:Vero Cells / Q000032:analysis
chemical_list: D034961:Antigens, Nuclear; D001323:Autoantibodies; D001324:Autoantigens; D009698:Nucleoproteins; D003609:Dactinomycin; D004004:Dichlororibofuranosylbenzimidazole