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G G Maul

Publications and source records attributed to G G Maul.

At least 55 records · Page 3Linked to original sources
PubMed1991

Identification of a novel nuclear domain.

For most known nuclear domains (ND), specific functions have been identified. In this report we used murine mAbs and human autoantibodies to investigate precisely circumscribed structures 0.2-0.3 micron in diameter which appear as "nuclear dots" distributed throughout the nucleoplasm. Nuclear dots are metabolically stable and resistant to nuclease digestion and salt extraction. The localization of nuclear dots is separate from kinetochores, centromeres, sites of mRNA processing and tRNA synthesis, nuclear bodies, and chromosomes. The nuclear dots, therefore, represent a novel ND. Nuclear dots break down as cells enter metaphase and reassemble at telophase. In interphase cells, nuclear dots are frequently "paired," and some are visible as "doublets" when stained with one particular antiserum. The number of dot doublets increased when quiescent cells were stimulated with serum although the total number of dots did not change substantially. One of the antigens was identified as a protein with a molecular mass of approximately 55 kD showing three charge isomers in the pI range of 7.4 to 7.7. Autoantibodies affinity purified from this nuclear dot protein (NDP-55) show nuclear dots exclusively. Nuclear dot-negative rat liver parenchymal cells became positive after chemical hepatectomy, suggesting involvement of the NDP-55 in the proliferative state of cells.

Amanitins↗
PubMed1990

Histologic and electron microscopic characterization of the antiperinuclear factor antigen.

The presence of the antiperinuclear factor, an autoantibody that recognizes cytoplasmic antigens, was detected in sera from patients with rheumatoid arthritis (59%), seronegative rheumatoid arthritis (36%), systemic lupus erythematosus (46%), systemic sclerosis (26%), and in nonautoimmune controls (10%). The antigenic perinuclear granules were found in the stratum intermedium layer of the buccal mucosa. Granules exhibited histologic features of nucleoproteins, stained for ribonucleoprotein, and showed the ultrastructural characteristics of aggregated rough endoplasmic reticulum. The antiperinuclear factor may recognize a common autoantigen in connective tissue disease.

Arthritis, Rheumatoid↗
PubMed1990

Antikinetochore and antitopoisomerase I antibodies in systemic scleroderma: comparative study using immunoblotted recombinant antigens, immunofluorescence, and double immunodiffusion.

In 135 patients with systemic scleroderma, we compared three different methods to determine antinuclear autoantibody (ANA) specificity: indirect immunofluorescence, double immunodiffusion, and, employing recombinant antigens, immunoblotting using both marker autoantigens of this disease. A characteristic Scl-70 antibody pattern was found on HEp-2 cells in 83.8% of the patients, double immunodiffusion was positive for the Scl-70 antibodies in 81.9%, and immunoblot with the recombinant topoisomerase I (Topo I) was positive in 71% of the patients. For the centromere autoantibodies we found a high concordance between the anticentromere antibody (ACA) pattern on HEp-2 cells (27 patients positive) and the detection of recombinant kinetochore in immunoblotting (26 patients positive). The three testing techniques gave comparable results, except that the Topo I recombinant antigen used in immunoblotting reacted strongly with fewer than expected of the known Scl-70-positive sera. However, a method using recombinant antigens expressing all epitopes (rather than one of the epitopes of Topo I) will undoubtedly become the method of choice for detecting antibodies in systemic scleroderma. Using the immunoblotting technique with the recombinant antigens we detected in four patients antibodies against both Topo I and kinetochore. More severe symptoms of systemic scleroderma were found in patients who had both antibodies. The combined presence of both marker autoantibodies is therefore not as rare as previously reported and may predict severe disease.

Adolescent↗
PubMed1990

A nucleolar auto-antigen is part of a major chromosomal surface component.

Several nucleolar antigens are defined by human autoantibodies. These antigens can therefore be used to follow the fate of nucleolar components through mitosis when this major nuclear structure disintegrates and becomes reassembled in G1-phase. We found that fibrillarin leaves the nucleolus before complete breakdown of this structure and attaches to chromosomes before nuclear envelope breakdown. In mouse, fibrillarin attaches over the chromosomal surface except for the excluded centromeric region. The antigen is transported to the new nucleus via the chromosomes and is last seen on chromosomal surfaces facing the cytoplasm during nuclear envelope reformation. Lamin B reappears on the same chromosomal surfaces before the nucleolar antigen is removed and aggregates for new nucleolar reformation in G1-phase cells. From our observations, we postulate that the antigen acts in concert with other proteins as a nuclear envelope equivalent by forming a protective sheath around the chromosome, that it excludes larger molecules, and helps to separate the chromosomes, in addition to segregation of the ribonucleoprotein (RNP) back to the nucleus for nucleolar reconstruction. We also suggest that the selective retention of these antigens from certain areas on individual chromosomes together with specific lamin B attachment over these chromosomal surfaces allows for a nonrandom positioning of chromosomes in the nucleus.

Animals↗
PubMed1990

Transient expression of full-length and truncated forms of the human nerve growth factor receptor.

To facilitate the characterization of nerve growth factor (NGF) receptor and mutated forms of the receptor, we have set up a rapid, efficient transient expression system utilizing COS cells. The human NGF receptor is a 427 amino acid protein with a hydrophobic signal sequence, a 222 amino acid extracellular domain, a single transmembrane domain and a 155 amino acid intracellular domain. The NGF receptor and a truncated form lacking the cytoplasmic domain were expressed in a COS cell expression system. Both recombinant proteins were detected on the cell surface and at a perinuclear site. Specific binding of 125I-NGF to the recombinant proteins was detected by chemical cross-linking. The extracellular domain of the NGF receptor was also expressed in the same system and detected in the COS cell endoplasmic reticulum and in the culture supernatant. This recombinant protein also specifically binds NGF.

Animals↗
PubMed1990

Are ACA and Scl 70 antibodies mutually exclusive?

Serological studies using indirect immunofluorescence, double immunodiffusion and immunoblot with recombinant Topo I and kinetochore antigens were performed in 180 patients with systemic scleroderma. In the sera of 10 patients, we found coexisting ACA and Scl 70 antibodies, and this was confirmed by all three methods. The relationship between the coexistence of these antibodies and the clinical features of the disease is not clear, although in all these cases there was pronounced vascular involvement.

Adult↗
PubMed1989

Determination of an epitope of the diffuse systemic sclerosis marker antigen DNA topoisomerase I: sequence similarity with retroviral p30gag protein suggests a possible cause for autoimmunity in systemic sclerosis.

The possibility that viruses play a role in the etiology of various autoimmune diseases has been proposed. One approach to the search for these agents involves identifying potential crossreactive epitopes in viruses that infect cells of the immune system or of the target tissues. Antibodies to DNA topoisomerase I are the marker autoantibodies for diffuse systemic sclerosis. The major epitope of the antigen was therefore sought through cloning and sequencing of the cDNA for human topoisomerase I and eventually by the synthesis of the smallest possible peptide recognized by sera from patients with the diffuse form of systemic sclerosis. The antigenic 11-amino acid sequence contains 6 sequential amino acids that are identical to a sequence present in the group-specific antigen (p30gag) of some mammalian retroviruses. This sequence is separated by only 1 amino acid from the retroviral epitope sequence that crossreacts with autoantibodies against the marker antigen for mixed connective-tissue disease and systemic lupus erythematosus, the 70-kDa polypeptide of U1 ribonucleoprotein particles. These findings suggest that a retroviral agent may be involved in the pathogenesis of systemic sclerosis and other connective tissue diseases and that antibodies to intracellular antigens are not involved in the pathogenesis of autoimmune disease but may be useful as footprints for tracking the potential etiological agent of autoimmune disease.

Amino Acid Sequence↗
PubMed1989

Nuclear lamin antigens are developmentally regulated during porcine and bovine embryogenesis.

The nuclear lamins, proteins that reside on the inner face of the nuclear envelope, are thought to provide attachment sites for anchoring the chromatin to the nuclear envelope, thus facilitating the overall organization of the nucleus. The composition of the nuclear lamin proteins changes during differentiation and development in a variety of mammalian and nonmammalian tissues. Bovine and porcine oocytes and early embryos were prepared for immunocytochemical detection of nuclear lamins using three different antibodies (recognizing lamin B, lamins A/B/C, or lamins A/C). In both species, germinal vesicle nuclei and early cleavage stage nuclei react positively with the antibodies. However, on nuclei of bovine embryos, the A/C epitope was not detectable at the 16-cell stage, compact morula, spherical blastocyst, or the chorionic cell nuclei of a Day 35 conceptus, but was detectable on both amniotic and embryonic ectodermal cell nuclei of a Day 35 conceptus. All three antibodies reacted with nuclei from two bovine tissue culture cell lines (bovine embryonic cells and Madin-Darby bovine kidney cells) and one porcine kidney cell line. Nuclei in porcine embryos followed a similar pattern, except the loss of the A/C epitope occurred at the 8-cell stage and the epitope was absent from compact morula and spherical blastocyst stage nuclei. All interphase nuclei in both species reacted with both anti-lamin A/B/C and anti-lamin B antibodies, whereas metaphase chromosomes did not react with any of the lamin antibodies tested. The change in recognizing the lamin epitope occurred one cell cycle after the expected transition from maternal control to zygotic control of development. Nuclear transplantation showed that 16-cell stage porcine nuclei, which are lamin A/C negative, acquired the A/C epitope after transfer to an enucleated metaphase II oocyte. These results suggest that the A/C epitope is developmentally regulated.

Animals↗
PubMed1988

A novel antinuclear antibody associated with a lupus-like paraneoplastic syndrome.

The association of malignancy with lupus-like syndromes is rare, and the relation between these two processes is uncertain. A 71-year-old woman who presented with serositis, Raynaud phenomenon, and positive results on an antinuclear antibody test was initially thought to have systemic lupus erythematosus but was found to have ovarian adenocarcinoma. A unique sparsely speckled antinuclear antibody pattern was seen. The patient's sera reacted to novel antigens with six bands of 100, 80-78, 48, and 17 kD on Western blots not typical of reactivity for sera from patients with systemic lupus erythematosus.

Adenocarcinoma, Papillary↗
PubMed1987

Detection of nuclear lamin B epitopes in oocyte nuclei from mice, sea urchins, and clams using a human autoimmune serum.

Somatic nuclei typically contain two or three major proteins, the lamins A, B, and C or their antigenically related equivalents, interspersed between the chromatin and its attachment site, the inner nuclear membrane. The late oocyte nuclear envelopes of the previously investigated Xenopus and Spisula germinal vesicles, however, have no chromatin attached and only one lamin-like protein. Since mouse and sea urchin germinal vesicles have chromatin attached, we tested them for the possible presence of more than one lamin. In both species we found two different lamins incorporated in their nuclear envelope structure. One lamin is recognized by anti-lamin B and the other by anti-lamin AC antibodies. Spisula germinal vesicles were found to contain not only the nuclear envelope-bound lamin (clamin), but also a 65-kDa protein cross-reactive with anti-lamin B antibodies. This protein is present unattached to any structure and is apparently soluble. Our findings provide a possible explanation of the early presence of lamin B in pronuclei of mouse and sea urchin contrary to the late appearance of a lamin B equivalent in amphibian embryos. In Spisula, as in Xenopus, the presence of a lamin B equivalent could not be documented in the nuclear envelopes of early embryos, indicating that a separate lamin B equivalent is not essential for chromatin binding to the envelope in these species during early embryogenesis. The results also indicate that the nuclear complement of structural proteins might vary substantially in the same cell type of different species.

Animals↗
PubMed1986

Screening cDNA expression libraries with monoclonal and polyclonal antibodies using an amplified biotin-avidin-peroxidase technique.

A chromogenic method using biotinylated secondary antibodies and peroxidase-coupled avidin for screening cDNA expression libraries is described. This method offers increased sensitivity over peroxidase-coupled secondary antibodies and rapid processing of samples, and avoids preparation and handling of radioactive materials. All materials for the chromogenic assay are available commercially and the method offers a fast and easy way to screen lambda and plasmid expression libraries with mono- and polyclonal antibodies.

Animals↗
PubMed1986

Identification and redistribution of lamins during nuclear differentiation in mouse spermatogenesis.

Chromatin may be attached to the nuclear envelope through interaction of the nuclear membrane lamins A, B, and C. Such a hypothesis requires that these proteins are present in all cells with chromatin attachment to the nuclear envelope. We have investigated the distribution of the lamins during spermatogenesis in mouse, which exhibits extremes in nuclear envelope structural changes. By immunohistochemical techniques using human auto-antibodies and monoclonal antibodies against these molecules, we found that the lamins persist through all stages of spermatogenesis, though in highly variable amounts. They are also present during meiotic prophase (pachytene) when chromosomes are only locally attached to the nuclear envelope, analogous to the early prophase of somatic cells. Restructuring of the early spermatid nuclear envelope is accompanied by the appearance of a new lamin at the acrosomal fossa. In the epididymal spermatozoon the distribution of different lamins varies markedly over the nucleus suggesting special structural functions. The presence of lamins throughout spermatogenesis supports the concept that they are a general feature of the nuclear envelope structure, even where a lamina is not recognizable ultrastructurally.

Acrosome↗
PubMed1986

Topoisomerase I identified by scleroderma 70 antisera: enrichment of topoisomerase I at the centromere in mouse mitotic cells before anaphase.

Antibodies derived from scleroderma patients positive for the extractable 70-kDa antigen were shown to react with topoisomerase I. Topoisomerase I was identified by molecular size and by antibody inhibition of the topoisomerase I-specific relaxation of supercoiled plasmid DNA. By using in situ localization by indirect fluorescence, we found topoisomerase I preferentially located in the centromeric regions of the mouse G2-phase cells and chromosomes, while the distribution in human cells is much more dispersed. Moreover, comparison of a published consensus sequence for topoisomerase I binding with mouse satellite DNA revealed a high degree of homology. The localization of topoisomerase I in the centromeres of mouse cells in the later part of the cell cycle and prior to anaphase suggests functional involvement in mitosis.

Animals↗
PubMed1985

Nuclear lamins and peripheral nuclear antigens during fertilization and embryogenesis in mice and sea urchins.

Nuclear structural changes during fertilization and embryogenesis in mice and in sea urchins have been followed by using antibodies against the nuclear lamins A/C and B and against antigens at the periphery of nuclei and chromosomes. Lamins are found on all pronuclei and nuclei during mouse fertilization, but with a diminished intensity on the second polar body nucleus. On sperm in both systems, lamins are reduced and detected only at the acrosomal and centriolar fossae. In sea urchin eggs, lamins are found on both pronuclei. Unlike in other dividing cells, the mitotic chromosomes of sea urchin eggs and embryos retain an association with lamins. The peripheral antibodies delineate each chromosome and nucleus except the mature mouse sperm nucleus. A dramatic change from the expected lamin distribution occurs during early development. In mouse morulae or blastocysts, lamins A/C are no longer recognized, although lamin B remains. In sea urchins both lamins A/C and lamin B, as detected with polyclonal antibodies, are lost after the blastula stage, although a different lamin A/C epitope emerges as recognized by a monoclonal antibody. These results demonstrate that pronucleus formation in both systems involves a new association or exposure of lamins, that the polar body nucleus is largely restricted from the cytoplasmic pool of lamins, and that mitotic chromosomes in the rapidly proliferating sea urchin egg retain associated lamins. They also suggest that changes in the expression or exposure of different lamins are a common feature of embryogenesis.

Animals↗
PubMed1985

Primary melanoma cells of the vertical growth phase: similarities to metastatic cells.

Three primary and 16 metastatic melanoma cell lines were established from primary and metastatic lesions of 4 patients with malignant melanoma. Comparison of metastatic melanoma cells with cells of the vertical growth phase (VGP) or late primary melanoma from the same individual revealed, generally, a shorter population-doubling time, growth to a higher cell density, higher tyrosinase activity, and more pigmentation in metastatic cells. Conversely, primary and metastatic melanoma cells had similar morphology, plating efficiency, and tumorigenicity in nude mice. Karyotypic analysis revealed clonality and nonrandom abnormalities in chromosomes 1, 6, and 7 in cells of the primary and metastatic lesions of the 3 patients studied. Few differences were found in the expression of melanoma-associated antigens on short-term and long-term cultured cells by tests with monoclonal antibodies in mixed hemadsorption assays, flow cytometry, and radioimmunoassays. Our results indicate that cells cultured from the VGP but not from the radial growth phase of primary melanoma are similar to metastatic melanoma cells.

Antigens, Neoplasm↗
PubMed1984

[3H]UTP incorporation in permeabilized mouse L-cells is inhibited by antibodies directed against a structural nuclear protein.

Newly transcribed RNA is apparently attached to a nuclear structural framework whose main proteins are lamins A, C and B. Whether this attachment is fortuitous or has some functional importance was tested by measuring [3H]UTP incorporation into RNA of permeabilized mouse L-cells after incubation with antibodies against these polypeptides. Antibodies against only lamin B and not against lamins A, C inhibited low concentration alpha-amanitin-sensitive RNA transcription. Lamin B antibodies inhibited only in an assay system with whole nuclei and not in a soluble assay system. Anti-lamin B therefore does not block the actual transcriptional machinery, but rather seems to crosslink the structural framework on which transcription takes place in the intact nucleus, inhibiting dynamic changes essential to RNA synthesis.

Animals↗