201
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Reuter R, Tessars G, Vohr HW, Gleichmann E, Lührmann R. Mercuric chloride induces autoantibodies against U3 small nuclear ribonucleoprotein in susceptible mice. Proc Natl Acad Sci U S A 1989; 86:237-41. [PMID: 2521387 PMCID: PMC286439 DOI: 10.1073/pnas.86.1.237] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Autoantibodies to nucleolar components are a common serological feature of patients suffering from scleroderma, a collagen vascular autoimmune disease. While animal models, which spontaneously develop abundant anti-nucleolar antibodies, have not yet been described, high titers of such antibodies may be induced by treating susceptible strains of mice with mercuric chloride. We have identified the nucleolar autoantigen against which the HgCl2-induced IgG autoantibodies from mice of strain B10.S are directed. It is a protein with an apparent molecular mass of 36 kDa and a pI value of approximately 8.6, which is associated with the nucleolar small nuclear RNA U3, and by these criteria must be identical with a polypeptide called fibrillarin. It is striking that scleroderma patients spontaneously produce autoantibodies against the same U3 ribonucleoprotein (RNP). The HgCl2-induced murine and the scleroderma-specific human anti-U3 RNP autoantibodies were indistinguishable in their reactivities toward fibrillarin. They further resemble each other insofar as both recognize epitopes on the 36-kDa protein, which have been highly conserved throughout evolution. Our results provide a basis to investigate at the molecular level whether similar immunoregulatory dysfunctions may lead to the preferential anti-U3 RNP autoantibody production in the animal model and in scleroderma patients.
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Affiliation(s)
- R Reuter
- Max-Planck-Institut für Molekulare Genetik, Otto-Warburg-Laboratorium, Berlin, Federal Republic of Germany
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202
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Tan EM. Antinuclear antibodies: diagnostic markers for autoimmune diseases and probes for cell biology. Adv Immunol 1989; 44:93-151. [PMID: 2646863 DOI: 10.1016/s0065-2776(08)60641-0] [Citation(s) in RCA: 1081] [Impact Index Per Article: 30.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Affiliation(s)
- E M Tan
- W. M. Keck Autoimmune Disease Center, Scripps Clinic and Research Foundation, La Jolla, California 92037
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203
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Parker KA, Bruzik JP, Steitz JA. An in vitro interaction between the human U3 snRNP and 28S rRNA sequences near the alpha-sarcin site. Nucleic Acids Res 1988; 16:10493-509. [PMID: 2974535 PMCID: PMC338920 DOI: 10.1093/nar/16.22.10493] [Citation(s) in RCA: 34] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Model transcripts containing mammalian pre-rRNA sequences were incubated with a HeLa cell extract, digested with T1 RNase, and immunoprecipitated with anti-(U3)RNP or control antibodies. Two overlapping fragments derived from the 3' domain of human 28S rRNA were specifically immunoprecipitated although transcripts which spanned the transcription initiation site, the ETS processing site, the 5' end of 18S, and both termini of 5.8S yielded no protected fragments. The sequence of these fragments was determined using a novel technique in which the [32P]-labeled fragment was co-finger-printed with [3H]-labeled total transcript serving as an internal marker. The fragments immunoprecipitated derive from nucleotides 4570-4590 and 4575-4590 of human 28S and are adjacent to the alpha-sarcin site. Protection most likely involves the U3 RNA since it is sensitive to pretreatment of the extract with micrococcal nuclease. Complementarity between U3 and this rRNA region is phylogenetically conserved in species ranging from human to S. cerevisiae. The possible significance of this finding is discussed.
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Affiliation(s)
- K A Parker
- Department of Molecular Biophysics and Biochemistry, Howard Hughes Medical Institute, Yale University Medical School, New Haven, CT 06510
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204
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Benavente R, Reimer G, Rose KM, Hügle-Dörr B, Scheer U. Nucleolar changes after microinjection of antibodies to RNA polymerase I into the nucleus of mammalian cells. Chromosoma 1988; 97:115-23. [PMID: 3229176 DOI: 10.1007/bf00327368] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
After microinjection of antibodies against RNA polymerase I into the nuclei of cultured rat kangaroo (PtK2) and rat (RVF-SMC) cells alterations in nucleolar structure and composition were observed. These were detected by electron microscopy and double-label immunofluorescence microscopy using antibodies to proteins representative of the three major components of the nucleolus. The microinjected antibodies produced a progressive loss of the material of the dense fibrillar component (DFC) from the nucleoli which, at 4 h after injection, were transformed into bodies with purely granular component (GC) structure with attached fibrillar centers (FCs). Concomitantly, numerous extranucleolar aggregates appeared in the nucleoplasm which morphologically resembled fragments of the DFC and contained a protein (fibrillarin) diagnostic for this nucleolar structure. These observations indicate that the topological distribution of the material constituting the DFC can be experimentally influenced in interphase cells, apparently by modulating the transcriptional activity of the rRNA genes. These effects are different from nucleolar lesions induced by inhibitory drugs such as actinomycin D-dependent "nucleolar segregation". The structural alterations induced by antibodies to RNA polymerase I resemble, however, the initial events of nucleolar disintegration during mitotic prophase.
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Affiliation(s)
- R Benavente
- Institute of Zoology I, University of Würzburg, Federal Republic of Germany
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205
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Benavente R, Schmidt-Zachmann MS, Hügle-Dörr B, Reimer G, Rose KM, Scheer U. Identification and definition of nucleolus-related fibrillar bodies in micronucleated cells. Exp Cell Res 1988; 178:518-23. [PMID: 3049124 DOI: 10.1016/0014-4827(88)90420-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Small nucleolus-related bodies which occur in the nucleoplasm of "micronuclei" lacking nucleolar organizers have been studied by immunofluorescence microscopy. These bodies stained specifically with three different antibodies directed against proteins that are normally associated with the dense fibrillar component of functional nucleoli, but not with antibodies specific for certain proteins of the granular component or the fibrillar centers. Our data show that, in the absence of rRNA genes, the various constituent proteins characteristic of the dense fibrillar component spontaneously assemble into spherical entities but that the subsequent fusion of these bodies into larger structures is prevented in these micronuclei. The similarity between these nucleolus-related bodies of micronuclei and the prenucleolar bodies characteristic of early stages of nucleologenesis during mitotic telophase is discussed.
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Affiliation(s)
- R Benavente
- Institute of Zoology I, University of Würzburg, Federal Republic of Germany
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206
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Aris JP, Blobel G. Identification and characterization of a yeast nucleolar protein that is similar to a rat liver nucleolar protein. J Cell Biol 1988; 107:17-31. [PMID: 3292539 PMCID: PMC2115186 DOI: 10.1083/jcb.107.1.17] [Citation(s) in RCA: 223] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
We have produced monoclonal antibodies against purified nuclei from the yeast Saccharomyces cerevisiae and have characterized three different antibodies that recognize a protein with an apparent molecular weight of 38,000, termed p38. Subcellular fractionation shows that virtually all of p38 occurs in the nuclear fraction. High concentrations of salt (1 M) or urea (6 M) effectively solubilize p38 from a nuclear envelope fraction prepared by digestion of nuclei with DNase. Indirect immunofluorescence demonstrates a crescent shaped distribution of p38 at the inner periphery of the nucleus, with p38 extending between dividing pairs of cells during (closed) mitosis. Postembedding immunogold electron microscopy shows decoration of the densely stained "crescent" region of the yeast nucleus, confirming the localization of p38 to the nucleolus. One of the monoclonals, D77, cross reacts on immunoblots with a single protein of molecular weight 37,000 from purified rat liver nuclei. Indirect immunofluorescence localizes this protein to the nucleolus, and shows that it is dispersed throughout the cell during mitosis. The yeast and rat liver nucleolar proteins behave similarly when electrophoresed in two dimensions, and appear to have basic pI values. Analysis of immunological cross-reactivity using D77, and antibodies specific for nucleolar proteins from other sources, suggests that the rat liver protein is fibrillarin, and demonstrates that p38 shares epitopes with fibrillarin, as well as with other vertebrate nucleolar proteins.
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Affiliation(s)
- J P Aris
- Laboratory of Cell Biology, Howard Hughes Medical Institute, Rockefeller University, New York 10021
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207
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Reimer G, Raska I, Scheer U, Tan EM. Immunolocalization of 7-2-ribonucleoprotein in the granular component of the nucleolus. Exp Cell Res 1988; 176:117-28. [PMID: 3286276 DOI: 10.1016/0014-4827(88)90126-7] [Citation(s) in RCA: 100] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Certain autoimmune sera contain antibodies against a nucleolar ribonucleoprotein particle associated with 7-2-RNA (R. Reddy et al. (1983) J. Biol. Chem. 258, 1383; C. Hashimoto and J. A. Steitz (1983) J. Biol. Chem. 258, 1379). In this study, we showed by immunofluorescence microscopy that antibodies reactive with 7-2-ribonucleoprotein immunolocalized in the granular regions of actinomycin D and 5,6-dichloro-1-beta-D-ribofurano-sylbenzimidazole (DRB)--segregated nucleoli from Vero cells. By electron microscopic immunocytochemistry, antigen-antibody complexes were located in the granular component of transcriptionally active nucleoli from rat liver hepatocytes and HeLa cells. Anti-7-2-RNP antibodies from two autoimmune sera immunoprecipitated a major protein of Mr 40,000 from [35S] methionine--labeled HeLa cell extract. The immunolocalization data suggest that 7-2-ribonucleoprotein may be involved in stages of ribosome biogenesis which take place in the granular component of the nucleolus, i.e., assembly, maturation, and/or transport of preribosomes.
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Affiliation(s)
- G Reimer
- Department of Dermatology, University of Erlangen-Nürnberg, Federal Republic of Germany
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208
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Tan EM, Chan EK, Sullivan KF, Rubin RL. Antinuclear antibodies (ANAs): diagnostically specific immune markers and clues toward the understanding of systemic autoimmunity. CLINICAL IMMUNOLOGY AND IMMUNOPATHOLOGY 1988; 47:121-41. [PMID: 3280190 DOI: 10.1016/0090-1229(88)90066-9] [Citation(s) in RCA: 228] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The convergence of studies in the clinical and basic sciences has resulted in the definitive identification of many intracellular antigens which are the targets of autoantibodies in patients with systemic lupus erythematosus, scleroderma, dermatomyositis/polymyositis, Sjogren's syndrome, mixed connective tissue disease, and drug-induced autoimmunity. Some of this new knowledge includes the identification of the Sm and RNP antigens as ribonucleoprotein particles involved in splicing of precursor messenger RNA, Scl-70 as DNA topoisomerase I, proliferating cell nuclear antigen as auxiliary protein of DNA polymerase delta, and certain antigens in myositis as aminoacyl transfer RNA synthetases. This information confirms, at a molecular level, the presence of specific profiles of autoimmune responses so that autoantibodies can be used in clinical medicine as diagnostically useful immune markers. In addition the data give compelling reasons to consider that certain autoimmune diseases are antigen-driven. Many auto-antibodies have the interesting feature of recognizing epitopes on the antigens which are active or functional sites of the molecule. It is suggested that the data provide clues to the nature of the intracellular particle initiating the immune response and may help to elucidate some of the early mechanisms of the autoimmune process.
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Affiliation(s)
- E M Tan
- W. M. Keck Autoimmune Disease Center, Scripps Clinic and Research Foundation, La Jolla, California 92037
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209
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Reimer G, Steen VD, Penning CA, Medsger TA, Tan EM. Correlates between autoantibodies to nucleolar antigens and clinical features in patients with systemic sclerosis (scleroderma). ARTHRITIS AND RHEUMATISM 1988; 31:525-32. [PMID: 2451921 DOI: 10.1002/art.1780310409] [Citation(s) in RCA: 165] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Immunofluorescence on rat liver sections was used to select high-titer antinucleolar antibodies (ANoA) in the sera of patients with systemic sclerosis (scleroderma). In 646 patients, 53 ANoA sera (8%) were identified, and of these, 46 were available in sufficient quantities for further analysis. The complex of RNA polymerase I was immunoprecipitated by 7 sera (15%), which uniformly produced punctate nucleolar staining. The PM-Scl antigen, a particle consisting of 11 polypeptides, was immunoprecipitated by 8 sera (17%), all of which displayed homogeneous nucleolar staining. A 34-kd nucleolar protein (fibrillarin) of the U3 RNP complex was positive in immunoblotting of 22 sera (48%), which characteristically produced clumpy nucleolar staining. Antibodies against RNA polymerase I were associated with diffuse scleroderma of short duration, which was characterized by a high prevalence of internal organ involvement, including renal crisis. Anti-U3 RNP antibodies had a high prevalence in men with significantly less joint involvement, compared with ANoA-negative patients. Anti-PM-Scl antibodies identified a group of scleroderma patients with a high prevalence of concomitant myositis and renal involvement.
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Affiliation(s)
- G Reimer
- W. M. Keck Autoimmune Disease Center, Scripps Clinic and Research Foundation, La Jolla, CA 92037
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210
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Reimer G, Raska I, Tan EM, Scheer U. Human autoantibodies: probes for nucleolus structure and function. VIRCHOWS ARCHIV. B, CELL PATHOLOGY INCLUDING MOLECULAR PATHOLOGY 1987; 54:131-43. [PMID: 2894087 DOI: 10.1007/bf02899205] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- G Reimer
- Department of Dermatology, University of Erlangen-Nürnberg, Federal Republic of Germany
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211
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Benavente R, Rose KM, Reimer G, Hügle-Dörr B, Scheer U. Inhibition of nucleolar reformation after microinjection of antibodies to RNA polymerase I into mitotic cells. J Cell Biol 1987; 105:1483-91. [PMID: 3312231 PMCID: PMC2114661 DOI: 10.1083/jcb.105.4.1483] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
The formation of daughter nuclei and the reformation of nucleolar structures was studied after microinjection of antibodies to RNA polymerase I into dividing cultured cells (PtK2). The fate of several nucleolar proteins representing the three main structural subcomponents of the nucleolus was examined by immunofluorescence and electron microscopy. The results show that the RNA polymerase I antibodies do not interfere with normal mitotic progression or the early steps of nucleologenesis, i.e., the aggregation of nucleolar material into prenucleolar bodies. However, they inhibit the telophasic coalescence of the prenucleolar bodies into the chromosomal nucleolar organizer regions, thus preventing the formation of new nucleoli. These prenucleolar bodies show a fibrillar organization that also compositionally resembles the dense fibrillar component of interphase nucleoli. We conclude that during normal nucleologenesis the dense fibrillar component forms from preformed entities around nucleolar organizer regions, and that this association seems to be dependent on the presence of an active form of RNA polymerase I.
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Affiliation(s)
- R Benavente
- Division of Membrane Biology and Biochemistry, German Cancer Research Center, Heidelberg
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