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H Busch

Publications and source records attributed to H Busch.

At least 163 records · Page 9Linked to original sources
PubMed1984

Further studies on satellite nucleoli in rat and mouse hepatocytes.

To provide more information on satellite nucleoli, these nuclear structures were studied by means of cytochemical and immunofluorescence procedures in rat and mouse hepatocytes without and following experimental inhibition of the RNA synthesis. The immuno-staining specific for nucleoli or B23 as well as C23 proteins demonstrated that satellite nucleoli and characteristic nucleoli exhibit the same fluorescence. The number of satellite nucleoli decreased after inhibition of nucleolar RNA synthesis in a similar way to the number of silver-stained granules (SSGs) of characteristic nucleoli. Inhibition of RNA synthesis also reduced the number of hepatocytes containing satellite nucleoli. Thus, satellite nucleoli seem to be real nucleoli from single NORs which did not fuse in the formation of a characteristic nucleolus.

Animals↗
PubMed1983

Isolation and partial characterization of dinoflagellate U1-U6 small RNAs homologous to rat U small nuclear RNAs.

The dinoflagellates are a group of diverse eukaryotic algae possessing a number of unique cellular properties. Evidence is presented for the presence of six capped small nuclear RNAs in these dinoflagellates. By several criteria such as the (a) presence of trimethylguanosine cap structure in U1 to U5 RNAs, (b) sequence homology between rat and dinoflagellate U2, U5 and U6 RNAs, (c) presence of other post-transcriptional modifications such as sugar and base modifications, and (d) association of Sm antigen with five of these six RNAs, the six RNAs of dinoflagellates appear to be similar to the well characterized U1 to U6 RNAs found in higher eukaryotes. This is the first demonstration of antigenic small nuclear RNA-containing particles in any unicellular organism. These results suggest that the U1 to U6 RNAs and the associated Sm antigen evolved at a very early stage of eukaryotic evolution. With respect to U small nuclear RNAs and their associated proteins, the dinoflagellates appear to exhibit eukaryotic characteristics.

Animals↗
PubMed1983

Identification of a La protein binding site in a RNA polymerase III transcript (4.5 I RNA).

Anti-La antibodies are frequently found in patients with autoimmune diseases; the antigen was reported to be a 50,000-Da protein (Rinke, J., and Steitz, J. A. (1982) Cell 29, 149-159). Because this protein was associated with many nascent RNA polymerase III transcripts, it was suggested to be an RNA polymerase III transcription factor. The present study was designed to analyze 4.5 I ribonucleoprotein, an RNA polymerase III transcript which contains the La antigen. It was found that the 3'-end 20-30-nucleotide portion was the most protected portion of 4.5 I RNA when 4.5 I ribonucleoprotein was digested with T1 RNase. When U2 RNA (an RNA polymerase II transcript) and 4.5 I RNA were incubated with the S-100 fraction of Novikoff hepatoma cells, the 4.5 I RNA bound La antigen but the U2 RNA did not. When partial and complete T1 RNase digestion fragments of 4.5 I RNA were incubated with the S-100 fraction, the 3'-end fragments bound preferentially to the La antigen. However, the fragments of 4.5 I RNA bound less efficiently to La antigen than whole 4.5 I RNA. These results indicate that the 3'-end of 4.5 I RNA is the La antigen binding site in this molecule and suggest that the overall conformation of RNA aids in the binding of La antigen.

Animals↗
PubMed1983

Phosphorylation of purified Novikoff hepatoma topoisomerase I.

The purified Novikoff hepatoma nuclear phosphoprotein with a molecular weight of 110 kdalton and pI 8.4, was found to be a type I topoisomerase. When isolated from 32P-labeled Novikoff ascites cells or incubated in vitro with protein kinase, phosphoserine was found to be its major phosphorylated amino acid. The enzymatic activity of topoisomerase I was altered by changes in phosphorylation. Its activity was increased by protein kinase and it was decreased by alkaline phosphatase.

Alkaline Phosphatase↗
PubMed1983

Detection of a nucleolar 7-2 ribonucleoprotein and a cytoplasmic 8-2 ribonucleoprotein with autoantibodies from patients with scleroderma.

In studies on antinucleolar antibodies in sera from 24 patients with scleroderma, an autoimmune disease, one serum, designated "anti-To", contained antibodies against a nucleolar 7-2 ribonucleoprotein and a novel cytoplasmic 8-2 ribonucleoprotein. The 7-2 and 8-2 RNAs are distinct RNAs with a pppG terminus. They are partially conserved between rat and human species and are present in distinct ribonucleoprotein particles. Eight sera contained antibodies that precipitated particles containing nucleolar U3 RNA; these antibodies appear to be directed against preribosomal particles containing U3 ribonucleoprotein, rather than the U3 ribonucleoprotein particles alone. All these ribonucleoproteins required proteins for antigenicity. These antibodies will be of use in studies on the structure and function of these novel small ribonucleoproteins.

Animals↗
PubMed1983

The nucleotide sequence of 8 S RNA bound to preribosomal RNA of Novikoff hepatoma. The 5'-end of 8 S RNA is 5.8 S RNA.

8 S RNA of Novikoff hepatoma was characterized by fingerprinting, sequencing gels, and by hybridization to rat ribosomal DNA clones. The data obtained show that 8 S RNA is 273 or 274 nucleotides long; ribosomal 5.8 S RNA is its 5'-terminal 156 nucleotides. All the post-transcriptional modifications found in 5.8 S rRNA were also found in 8 S RNA; no other modifications were found. The 3'-terminal 118 nucleotides were consistent with the adjoining internal transcribed spacer sequence in rDNA (Subrahmanyam, C. S., Cassidy, B., Busch, H., and Rothblum, L. (1982) Nucleic Acids Res. 10, 3667-3680). Based on its nucleolar localization, the finding that all the 8 S RNA is hydrogen-bonded to preribosomal RNA and its consistency in sequence to the cloned rat ribosomal DNA sequence, it appears that 8 S RNA is a relatively stable intermediate in the formation of 5.8 S rRNA from 45 S pre-rRNA. This stable intermediate RNA may be a useful substrate for studies on rRNA processing and for studies on eukaryotic rRNA-processing enzyme(s).

Animals↗
PubMed1983

Proliferating cell nuclear antigen (PCNA) and human malignant tumor nucleolar antigens (HMTNA) in nucleoli of human hematological malignancies.

Lymphoma (Lymphocytic non-Hodgkin's malignant lymphoma) and leukemic (chronic lymphocytic, acute and chronic myeloid, myelomonocytic leukemia) cells were studied by indirect immunofluorescence to evaluate the presence of proliferating cell nuclear antigen (PCNA) and human malignant tumor nuclear antigen (HMTNA) in their nucleoli. Most cells in lymph node smears of lymphocytic non-Hodgkin's malignant lymphoma (NHML) developed a bright nucleolar fluorescence with HMTNA antibodies. PCNA was detected in nucleoli of a limited number of cells which apparently represent the proliferating cell population in these lymphomas. Similarly, in the bone marrow smears of patients with chronic lymphocytic leukemia most cells possessed a nucleolar fluorescence for HMTNA and PCNA was present in nucleoli of a limited number of cells. In the bone marrow smears of patients with myeloid or myelomonocytic leukemias most blastic or monocytoid cells also developed a bright nucleolar fluorescence with HMTNA antibodies and PCNA was present only in a small percentage of these cells. Leukemic cells with PCNA in their nucleoli like thekhuntigen might represent a proliferating cell population in late G1-early S phase.

Antigens, Neoplasm↗
PubMed1983

Identification and purification of Namalwa nuclear RNP antigen 52/5.3.

Using affinity purified rabbit antibodies to HeLa nucleoli and the Western blotting techniques, an antigen with an approximate molecular weight of 52,000 and pI of 5.3 was found in Namalwa cells (a Burkitt lymphoma), but not in normal liver cells. This antigen was purified from Namalwa RNP by column chromatography on Sephacryl S-200, hydroxylapatite and one-dimensional SDS gel electrophoresis. A liver protein with the same molecular weight and pI value was purified from RNP fraction by one-dimensional SDS gel electrophoresis. Both proteins had similar amino-acid compositions. The tryptic map of 125I-labeled protein 52/5.3 contained approximately nine major spots; spot 9 was present in the Namalwa protein but not in the liver protein. The similarity of the structures of these proteins and their differences in antigenicity are noteworthy and require further structural and functional analysis.

Amino Acids↗
PubMed1983

Localization of nucleolar phosphoproteins B23 and C23 during mitosis.

Nucleolar phosphoproteins B23 and C23 were simultaneously localized in unsynchronized male rat-kangaroo PtK2 cells during mitosis using a mouse monoclonal antibody against protein B23 and a rabbit antibody against protein C23. The distribution of proteins B23 and C23 during mitosis was compared with the distribution of the silver staining protein. During interphase, proteins B23 and C23 were both localized to the nucleolus. As the nucleolus disappeared in prophase, the distribution of protein B23 became nucleoplasmic, whereas most of protein C23 remained associated with the disappearing nucleolus. Throughout metaphase and anaphase protein B23 was found associated with the chromosomes, whereas protein C23 seemed to disappear. When the nucleolus reformed during telophase, protein C23 appeared first in 'prenucleolar bodies' and then in the nucleolus, whereas protein B23 did not appear in the nucleolus until late telophase or early G1 phase. Silver staining during mitosis closely paralleled the distribution of protein C23, supporting previous conclusions that protein C23 is a silver staining nucleolus organizer region (NOR) protein [19, 20].

Animals↗
PubMed1983

Elevated levels of a 17-kilodalton nuclear protein in carcinomas.

The presence of a 17-kilodalton nuclear protein with pI variants of 6.7-6.9 in solid human malignant tumors is reported. This protein was more prominent in the carcinomas sampled compared to the sarcomas studied. Small amounts were detectable in placenta, but not in adult human liver, suggesting that the protein may be the product of a gene involved in normal differentiation.

Adenocarcinoma↗
PubMed1983

Purification and partial characterization of ring-shaped miniparticles.

Small ring-shaped miniparticles, found in the nucleus nucleolus and cytoplasm of a variety of normal and malignant cells, have been purified by a procedure involving differential and gradient centrifugation, hydroxylapatite chromatography and preparative electrophoresis. They are multisubunit proteins comprised of at least six polypeptide chains of Mr 20,000-30,000 Daltons (by one-D SDS-PAGE which present a series of 20-30 spots on two-D IEF/SDS gels. They can be reversibly dissociated in EDTA containing buffers. They are not membrane associated and contain no carbohydrate. They have an S20,W of 21S on sucrose gradients. They are immunologically similar in several human cell lines.

Cell Fractionation↗
PubMed1983

Antibodies to a nucleolar protein are localized in the nucleolus after red blood cell-mediated microinjection.

To determine whether red blood cell-mediated microinjection of antibodies can be used to study nuclear protein localization and function, we microinjected antibodies that have been shown to react specifically with nucleolar acidic phosphoprotein C23 into Walker 256 cells. The intracellular distribution of microinjected anti-C23 antibodies and preimmune immunoglobulins were determined by immunofluorescence. At 3 h after microinjection, affinity-purified anti-C23 antibodies were localized in the cytoplasm and nucleolus. At 17 h after microinjection, the affinity-purified antibody was localized to those nucleolar structures previously shown to contain protein C23. Furthermore, the antibody remained localized in the nucleolus for at least 36 h after microinjection. In contrast to the results obtained with specific antibodies, preimmune immunoglobulins remained in the cytoplasm 36 h after microinjection. These results indicate that red blood cell-mediated microinjection of antibodies can be used to study nucleolar and nuclear antigens.

Animals↗
PubMed1983

Immunoelectron microscopic localization of snRNPs.

Small nuclear ribonucleoprotein particles (snRNPs) were identified in nuclear sonicates of Novikoff hepatoma ascites cells and in intact Novikoff hepatoma and PtK2 cells by immunofluorescence and immunoelectron microscopy. Auto-antibodies (anti-Sm and anti-RNP) obtained from patients with systemic lupus erythematosus an autoimmune disease, were used to localize snRNP particles. The Sm antibody is specific for U1, U2, U4, U5 and U6 containing snRNPs. The RNP antibody is specific for only U1 containing snRNPs. Isolated particles, 120 +/- 10 A in diameter, were found to be associated with ferritin-conjugated goat anti-human antibodies coupled to Sm antibodies. In addition, these particles (snRNPs) were occasionally associated with larger particles measuring 230 +/- 10 A in diameter which are presumed to be hnRNP particles. Double label immunofluorescence and immunoelectron microscopy have shown Sm and RNP antibodies to colocalize in PtK2 cells. However, the perinucleolar chromatin and juxtanuclear envelope chromatin was devoid of RNP immunostaining. Therefore, U1 containing snRNPs do not appear to be in these regions. The Sm antibody localizes in a nuclear network including the perinucleolar chromatin and juxtanuclear envelope chromatin. Cells treated with the drug DRB (5,6-dichloro-1-beta-D-ribofuranosylbenzimidazole), which inhibits hnRNA synthesis, show an altered pattern of Sm immunostaining. Such cells contain large clusters of snRNPs which do not extend to the perinucleolar chromatin or perinuclear lamina chromatin. Nuclear matrix preparations maintain an snRNP nuclear network as visualized by Sm immunofluorescence. It is notable that the size and density of the immunostained particles in the nuclear network during interphase, is similar to that of interchromatinic granules.

Animals↗
PubMed1983

Ultrastructural and purification studies on human tumor nucleolar antigens and nucleolar particles.

The presence of common nucleolar antigens in a broad array of human malignant tumors has led to several lines of investigations. In addition to studies on an increasing number of benign and malignant neoplasms with a variety of antibodies designed to statistically evaluate the presence of nucleolar antigens, purification procedures and chemical analyses are being used to characterize the specific antigens. The localization of the nucleolar antigens in HeLa cells was studied by the postembedding immunoelectron microscopic procedure employing rabbit antibodies to nucleoli or nuclear Tris extracts of these cells. The products of the peroxidase-antiperoxidase complexes visualized by the reaction with diaminobenzidine in nucleoli were mainly found in the nucleolonemas which contain the dense nucleolar RNP components. When these nucleoli became compact after treatment of HeLa cells with adriamycin, the distribution of the immunoreactive products was altered along with distribution of the dense nucleolar components. The human nucleolar antigens were mainly localized to nucleolar regions containing the nucleolar RNP components. Improved purification of the antigens made it possible to provide a satisfactory amino acid analysis of one pI 6.3 antigen. Interestingly, some of the nucleolar antigen was found in miniparticle undescribed until now.

Amino Acids↗
PubMed1983

A 38,000-dalton antigen found in Namalwa cells induced by Newcastle disease virus.

An antigen has been isolated from Namalwa cells, a Burkitt lymphoma line, that was induced by Newcastle disease virus (NDV) for interferon production. The antigen was extracted by 3 M NaCl from ribonucleoprotein particles (RNP), obtained from the nuclear 0.01 M Tris extract, and was purified by hydroxylapatite chromatography, phosphocellulose chromatography, and preparative sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Its molecular weight was 38 kilodalton (kDa) as determined by SDS-PAGE. The tryptic peptide map of 125I-labeled antigen contained seven major peptides. The antigen was not found in HeLa cells, normal human liver or in Namalwa cells that had not been induced by the virus. This result suggests that this antigen was produced in Namalwa cells as a result of induction by the NDV virus.

Animals↗