@inproceedings{ScheerTrendelenburgFranke1976,
  author    = {Scheer, Ulrich and Trendelenburg, M. F. and Franke, Werner W.},
  title     = {Regulation of transcription of ribosomal RNA genes during amphibian oogenesis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33700},
  year      = {1976},
  abstract  = {No abstract available},
  language  = {en}
}
@inproceedings{FrankeScheer1975,
  author    = {Franke, Werner W. and Scheer, Ulrich},
  title     = {Biochemical and structural aspects of nucleocytoplasmic transfer of ribonucleoproteins at the nuclear envelope level: facts and theses},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33766},
  year      = {1975},
  abstract  = {No abstract available},
  language  = {en}
}
@inproceedings{TrendelenburgFrankeSpringetal.1975,
  author    = {Trendelenburg, M. F. and Franke, Werner W. and Spring, H. and Scheer, Ulrich},
  title     = {Ultrastructure of transcription in the nucleoli of the green algae Acetabularia major and A. mediterranea},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33779},
  year      = {1975},
  abstract  = {No abstract available},
  language  = {en}
}
@inproceedings{FrankeScheer1974,
  author    = {Franke, Werner W. and Scheer, Ulrich},
  title     = {Pathways of nucleocytoplasmic translocation of ribonucleoproteins},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33832},
  year      = {1974},
  abstract  = {No abstract available},
  language  = {en}
}
@article{ScheerLanfranchiRoseetal.1983,
  author    = {Scheer, Ulrich and Lanfranchi, Gerolamo and Rose, Kathleen M. and Franke, Werner W. and Ringertz, Nils R.},
  title     = {Migration of rat RNA polymerase I into chick erythrocyte nuclei undergoing reactivation in chick-rat heterokaryons},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33232},
  year      = {1983},
  abstract  = {Transcriptionally inactive chick erythrocyte nudei were reactivated by Sendai virusinduced fusion of erythrocytes with rat L6j1 myoblasts. We used antibodies to trace the appearance of a specific protein engaged in transcription of a defined dass of genes, those coding for rRNA, during reactivation. Using immunofluorescence microscopy, we found increasing amounts of rat RNA polymerase I to appear, during a certain period of time after fusion, in the reforming nudeoli of the chick nudei. Amounts of rat RNA polymerase I sufficient to be detected by immunofluorescence microscopy had accumulated in the newly developed chick nudeoli 72- 190 h after fusion was initiated. This time interval coincides with the time when chick rRNA synthesis can first be detected. The results raise the possibility that during these stages of the reactivation process chick rRNA genes are transcribed by heterologous RNA polymerase I moleeules of rat origin.},
  language  = {en}
}
@article{ScheerHuegleHazanetal.1984,
  author    = {Scheer, Ulrich and H{\"u}gle, Barbara and Hazan, Rachel and Rose, Kathleen M.},
  title     = {Drug-induced dispersal of transcribed rRNA genes and transcriptional products: Immunolocalization and silver staining of different nucleolar components in rat cells treated with 5,6-dichloro-1-Beta-D-ribofuranosylbenzimidazole},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33216},
  year      = {1984},
  abstract  = {Upon incubation of cultured rat cells with the adenosine analogue 5,6-dichloro-l-\&\#946;- D-ribofuranosylbenzimidazole (DRB), nucleoli reversibly dissociate into their substructures, disperse throughout the nuclear interior, and form nucleolar "necklaces". We have used this experimental system, which does not inhibit transcription of the rRNA genes, to study by immunocytochemistry the distribution of active rRNA genes and their transcriptional products during nucleolar dispersal and recovery to normal morphology. Antibodies to RNA polymerase I allow detection of template-engaged polymerase, and monoclonal antibodies to a ribosomal protein (S 1) of the small ribosomal subunit permit localization of nucleolar preribosomal particles. The results show that, under the action of DRB transcribed rRNA, genes spread throughout the nucleoplasm and finally appear in the form of several rows, each containing several (up to 30) granules positive for RNA polymerase land argyrophilic proteins. Nucleolar material containing preribosomal particles also appears in granular structures spread over the nucleoplasm but its distribution is distinct from that of rRNA gene-containing granules. We conclude that, although transcriptional units and preribosomal particles are both redistributed in response to DRB, these entities retain their individuality as functionally defined subunits. We further propose that each RNA polymerase-positive granular unit represents a single transcription unit and that each continuous array of granules ("string of nucleolar beads") reflects the linear distribution of rRNA genes along a nucleolar organizer region. Based on the total number of polymerase I-positive granules we estimate that a minimum of 60 rRNA genes are active during interphase of DRB-treated rat cells.},
  language  = {en}
}
@article{ZentgrafTrendelenburgSpringetal.1979,
  author    = {Zentgraf, Hanswalter and Trendelenburg, Michael F. and Spring, Herbert and Scheer, Ulrich and Franke, Werner W. and M{\"u}ller, Ulrike and Drury, Kenneth C. and Rungger, Duri},
  title     = {Mitochondrial DNA arranged into chromatin-like structures after injection into amphibian oocyte nuclei},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33174},
  year      = {1979},
  abstract  = {Purified mitochondrial DNA (mitDNA) from ovaries ofXenopus lae vis was injected into the nuclei (germinal vesicles) of large viteUogenic oocytes of the same organism and examined by electron microscopy ofthe spread nuclear contents. Normally located nuclei of untreated oocytes as weil as peripherally translocated nuclei of centrifuged oocytes were used. In addition, oocyte nuclei isolated and incubated under liquid paraffin oil were injected with DNA. The integrity oftranscriptional structures of endogenous chromosomal (Iampbrush chromosomes) and extrachromosomal (nucleoli) genes of the injected nuclei was demonstrated. Microinjected mitDN A was identified as circles of chromatin exhibiting polynucleosome-like organization and a me an contour length of 2.6 J.Lm, corresponding to a compaction ratio of the mitDN A of about 2 : I. This DNA packing ratio is similar to that observed after preparation of various kinds of native chromatin in low salt buffers. The chromatin circles formed from injected mitDNA only very rarely exhibited lateral fibrils suggestive of transcriptional activity. These results suggest that purified mitDNA can be transformed to normally structured chromatin when exposed to oocyte nuclear contents but is rarely , if at all , transcribed in this form and in this environment.},
  language  = {en}
}
@inproceedings{ScheerRose1984,
  author    = {Scheer, Ulrich and Rose, Kathleen M.},
  title     = {Localization of RNA polymerase I in interphase cells and mitotic chromosomes by light and electron microscopic immunocytochemistry},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33223},
  year      = {1984},
  abstract  = {Rabbit antibodies to RNA polymerase I from a rat hepatoma have been used to localize the enzyme in a variety of cells at the light and electron microscopic level. In interphase cells the immunofluorescence pattern indicated that polymerase I is contained exclusively within the nucleolus. That this fluorescence, which appeared punctated rather than uniform, represented transcriptional complexes of RNA polymerase I and rRNA genes was suggested by the observation that it was enhanced in regenerating liver and in a hepatoma and was markedly diminished in cells treated with actinomycin D. Electron microscopic immunolocalization using gold-coupled second antibodies showed that transcribed rRNA genes are located in, and probably confined to, the fibrillar centers of the nucleolus. In contrast, the surrounding dense fibrillar component, previously thought to be the site of nascent prerRNA, did not contain detectable amounts of polymerase I. During mitosis, polymerase I molecules were detected by immunofluorescence microscopy at the chromosomal nucleolus organizer region, indicating that a considerable quantity of the enzyme remains bound to the rRNA genes. From this we conclude that rRNA genes loaded with polymerase I molecules are transmitted from one cell generation to the next one and that factors other than the polymerase itself are involved in the modulation of transcription of DNA containing rRNA genes during the cell cycle.},
  language  = {en}
}
@article{MorenoDiazdelaEspinaFrankeKrohneetal.1982,
  author    = {Moreno-Diaz de la Espina, Susana and Franke, Werner W. and Krohne, Georg and Trendelenburg, Michael F. and Grund, Christine and Scheer, Ulrich},
  title     = {Medusoid fibril bodies: a novel type of nuclear filament of diameter 8 to 12 nm with periodic ultrastructure demonstrated in oocytes of Xenopus laevis},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34116},
  year      = {1982},
  abstract  = {No abstract available},
  language  = {en}
}
@article{HadjiolovaRoseScheer1986,
  author    = {Hadjiolova, Krassimira and Rose, Kathleen M. and Scheer, Ulrich},
  title     = {Immunolocalization of nucleolar proteins after D-galactosamine-induced inhibition of transcription in rat hepatocytes},
  url       = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33205},
  year      = {1986},
  abstract  = {No abstract available},
  language  = {en}
}