@article{Scheer1972, author = {Scheer, Ulrich}, title = {The ultrastructure of the nuclear envelope of amphibian ooctyes: IV. On the chemical nature of the nuclear pore complex material}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39500}, year = {1972}, abstract = {In order to investigate the chemical composition of the nuclear pore complexes isolated nuclei from mature Xenopus laevis oocytes were manually fractioned into nucleo· plasmic aggregates and the nuclear envelopes. The whole isolation procedure takes no more than 60- 90 sec, and the pore complexes of the isolated envelopes are well preserved as demonstrated by electron microscopy. Minor nucleoplasmic and cytoplasmic contaminations associated with the isolated nuclear envelopes were determined with electron microscopic morphometry and were found to be quantitatively negligible as far as their mass and nucleic acid content is concerned. The RNA content of the fractions was determined by direct phosphorus analysis after differential alkaline hydrolysis. Approximately 9\% of the total nuclear RNA of the mature Xenopus egg was found to be attached to the nuclear envelope. The nonmembranous elements of one pore complex contain 0.41 X 10- 16 g RNA. This value agrees well with the content estimated from morphometric data. The RNA package density in the pore complexes (270 X 10- 15 g/fJ-3) is compared with the nucleolar, nucleoplasmic and cytoplasmic RNA concentration and is discussed in context with the importance of the pore complexes for the nucleo-cytoplasmic transport of RNA-containing macromolecules. Additionally, the results of the chemical analyses as well as of the 3H-actinomycin D autoradiography and of the nucleoprotein staining method of Bernhard (1969) speak against the occurence of considerable amounts of DNA in the nuclear pore complex structures.}, language = {en} } @article{Scheer1975, author = {Scheer, Ulrich}, title = {The rifamycin derivative AF/013 is cytolytic}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32429}, year = {1975}, abstract = {No abstract available}, language = {en} } @article{ScheerWeisenberger1994, author = {Scheer, Ulrich and Weisenberger, Dieter}, title = {The nucleolus}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-32037}, year = {1994}, abstract = {No abstract available}, language = {en} } @book{KartenbeckZentgrafScheeretal.1971, author = {Kartenbeck, J. and Zentgraf, H. and Scheer, Ulrich and Franke, Werner W.}, title = {The nuclear envelope in freeze-etching}, isbn = {3-540-05538-X}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40534}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1971}, abstract = {No abstract available}, subject = {Anatomie}, language = {en} } @article{ScheerDabauvalleMerkertetal.1988, author = {Scheer, Ulrich and Dabauvalle, Marie-Christine and Merkert, Hilde and Benavente, Ricardo}, title = {The nuclear envelope and the organization of the pore complexes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34275}, year = {1988}, abstract = {No abstract available}, language = {en} } @article{FrankeScheerKrohneetal.1981, author = {Franke, Werner W. and Scheer, Ulrich and Krohne, Georg and Jarasch, Ernst-Dieter}, title = {The nuclear envelope and the architecture of the nuclear periphery}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33108}, year = {1981}, abstract = {No abstract available}, language = {en} } @article{KrohneFrankeScheer1978, author = {Krohne, Georg and Franke, Werner W. and Scheer, Ulrich}, title = {The major polypeptides of the nuclear pore complex}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33078}, year = {1978}, abstract = {Nuclear envelopes of maturing oocytes of various amphibia contain an unusually high number of pore complexes in very close packing. Consequently, nuclear envelopes , which can be manually isolated in great purity, provide a remarkable enrichment of nuclear pore complex material, relative to membranous and other interporous structures. When the polypeptides of nuclear envelopes isolated from oocytes of Xenopl/s la evis and Triturus alpestris are examined by gel electrophoresis, visualized either by staining with Coomassie blue or by radiotluorography after in vitro reaction with [3H]dansyl chloride , a characteristic pattern is obtained (10 major and 15 minor bands). This polypeptide pattern is radically different from that of the nuclear contents isolated from the same cell. Extraction of the nuclear envelope with high salt concentrations and moderateIy ac tive detergents such as Triton X- 100 results in the removal of membrane material but leaves most of the non-membranous structure of the pore complexes. The dry weight of the pore complex (about 0.2 femtograms) remains essentially unchanged during such extractions as measured by quantitative electron microscopy . The extracted preparations which are highly enriched in nuclear pore complex material contain only two major polypeptide components with apparent molecular weights of 150000 and 73000. Components of such an electrophoretic mobility are not present as major bands , if at all , in nuclear contents extracted in the same way. lt is concluded that these two polypeptides are the major constituent protein(s) of the oocyte nuclear pore complex and are specific for this structure. When nuclear envelopes are isolated from rat liver and extracted with high salt buffers and Triton X- 100 similar bands are predominant, but two additional major components of molecular weights of 78000 and 66000 are also recognized. When the rat liver nuclear membranes are further subfractionated material enriched in the 66000 molecular weight component can be separated from the membrane material, indicating that this is relatively loosely associated material , probably a part of the nuclear matrix . The results suggest that the nuclear pore complex is not only a characteristic ubiquitous structure but also contains similar, if not identical , skeletal proteins that are remarkably re sistant to drastic changes of ionic strength as weil as to treatments with detergents and thiol reagents.}, language = {en} } @article{WeisenbergerScheerBenavente1993, author = {Weisenberger, Dieter and Scheer, Ulrich and Benavente, Ricardo}, title = {The DNA topoisomerase I inhibitor camptothecin blocks postmitotic reformation of nucleoli in mammmalian cells}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-41434}, year = {1993}, abstract = {No abstract available}, subject = {Cytologie}, language = {en} } @article{ReinhardHalbrueggeScheeretal.1992, author = {Reinhard, Matthias and Halbr{\"u}gge, Maria and Scheer, Ulrich and Wiegand, Christiane and Jockusch, Brigitte M. and Walter, Ulrich}, title = {The 46/50 kDa phosphoprotein VASP purified from human platelets is a novel protein associated with actin filaments and focal contacts}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-34246}, year = {1992}, abstract = {Vasoactive agents which elevate either cGMP or cAMP inhibit platelet activation by pathways sharing at least one component, the 46/50 kDa vasodilator-stimulated phosphoprotein (V ASP). V ASP is stoichiometrically phosphorylated by both cGMP-dependent and cAMPdependent protein kinases in intact human platelets, and its phosphorylation correlates very well with platelet inhibition caused by cGMP- and cAMP-elevating agents. Here we report that in human platelets spread on glass, V ASP is associated predominantly with the distal parts of radial micro filament bundles and with microfilaments outlining the periphery, whereas less V ASP is associated with a central microfilamentous ring. V ASP is also detectable in a variety of different cell types including fibroblasts and epithelial cells. In fibroblasts, V ASP is concentrated at focal contact areas, along microfilament bundles (stress fibres) in a punctate pattern, in the periphery of protruding lamellae, and is phosphorylated by cGMP- and cAMP-dependent protein kinases in response to appropriate stimuli. Evidence for the direct binding of V ASP to F -actin is also presented. The data demonstrate that V ASP is a novel phosphoprotein associated with actin filaments and focal contact areas, i.e. transmembrane junctions between microfilaments and the extracellular matrix.}, language = {de} } @inproceedings{FrankeZentgrafScheer1978, author = {Franke, Werner W. and Zentgraf, Hanswalter and Scheer, Ulrich}, title = {Supranucleosomal and non-nucleosomal chromatin configurations}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39447}, year = {1978}, abstract = {A significant contribution to the understanding of chromatin organization was the d iscovery of the nucleosome as a globular repeating unit of the package of DNA (Hewish and Burgoyne, 1973; Woodcock, 1973; Kornberg, 1974; Olins and Olins, 1974; for review see Oudet et al., 1978 a) . In accord with the original definition and in ag reement with most workers in this field of research we identify a nucleosome as a spheric alor slightly oblate gr anular particle 10-13 nm in diameter, containing about 200 base pairs of DNA and two of each of the four his tones H2a, H2b, H3 and H4. It is this structure in which the bulk of the nuclear chroma tin is organized in most eukaryotic cells, with the exception of the dinofl age llates (Rae and Steele, 1977; dinofl agellate DNA, however, c an be packed into nucleosoma l structures in vitro by addition of the appropriate amounts of histones;the same reference). Although it seems clear from the work reported that condensed and transcriptiona lly inactive chroma tin is contained in nucleosomes as the principle for first order p acking of DNA there are two important questions onto which we are focusing in the present study: ( i ) What is the higher order of p a cking present in - and perhaps typical-of - the condensed sta te of chromatin, and (ii) what is the specific form of arrangement of transcriptionally a ctive chromatin?}, language = {en} }