Autoantibody to RNA polymerase I in scleroderma sera.
Autoantibodies to components of the nucleolus are a unique serological feature of patients with scleroderma. There are autoantibodies of several specificities; one type produces a speckled pattern of nucleolar staining in immunofluorescence. In actinomycin D and 5,6-dichloro-beta-D-ribofuranosylbenzimidazole-treated Vero cells, staining was restricted to the fibrillar and not the granular regions. By double immunofluorescence, specific rabbit anti-RNA polymerase I antibodies stained the same fibrillar structures in drug-segregated nucleoli as scleroderma sera. Scleroderma sera immunoprecipitated 13 polypeptides from [35S]methionine-labeled HeLa cell extract with molecular weights ranging from 210,000 to 14,000. Similar polypeptides were precipitated by rabbit anti-RNA polymerase I antibodies, and their common identities were confirmed in immunoabsorption experiments. Microinjection of purified IgG from a patient with speckled nucleolar staining effectively inhibited ribosomal RNA transcription. Autoantibodies to RNA polymerase I were restricted to certain patients with scleroderma and were not found in other autoimmune diseases.
D000918:Antibody Specificity; D001323:Autoantibodies / Q000276:immunology*; D002466:Cell Nucleolus / Q000276:immunology; D000939:Epitopes; D006801:Humans; D007158:Immunologic Techniques; D008854:Microscopy, Electron; D008970:Molecular Weight; D010750:Phosphoproteins / Q000276:immunology; D012318:RNA Polymerase I / Q000276:immunology*; D012595:Scleroderma, Systemic / Q000276:immunology*
D001323:Autoantibodies; D000939:Epitopes; D010750:Phosphoproteins; D012318:RNA Polymerase I