3129
1992
eng
article
1
2009-08-28
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In vitro assembly of prenucleolar bodies in Xenopus egg extract
Nuclei assembled in Xenopus egg extract from purified DNA or chromatin resemble their natural counterparts in a number of structural and functional features. However, the most obvious structural element of normal interphase nuclei, the nucleolus, is absent from the in vitro reconstituted nuclei. By EM, cytological silver staining, and immunofluorescence microscopy employing antibodies directed against various nucleolar components we show that nuclei assembled in vitro contain numerous distinct aggregates that resemble prenucleolar bodies (PNBs) by several criteria. Formation of these PNB-like structures requires pore complex-mediated nuclear transport of proteins but is independent of the genetic content of the in vitro nuclei as well as transcriptional and translational events. Our data indicate that nuclei assembled in vitro are capable of initiating early steps of nucleologenesis but that the resulting PNBs are unable to fuse with each other, probably due to the absence of a functional nucleolus organizer. With appropriate modifications, this experimental system should be useful to define and analyze conditions promoting the site-specific assembly of PNBs into a coherent nucleolar body.
urn:nbn:de:bvb:20-opus-34233
3423
In: Journal of Cell Biology (1992) 118, 1297-1304.
Peter Bell
Marie-Christine Dabauvalle
Ulrich Scheer
Biowissenschaften; Biologie
open_access
Theodor-Boveri-Institut für Biowissenschaften
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/3129/Scheer_Vitro_prenucleolar.pdf
3132
1992
deu
article
1
2009-09-02
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The 46/50 kDa phosphoprotein VASP purified from human platelets is a novel protein associated with actin filaments and focal contacts
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.
urn:nbn:de:bvb:20-opus-34246
3424
In: EMBO J. (1992) 11, 6, 2063-2070.
Matthias Reinhard
Maria Halbrügge
Ulrich Scheer
Christiane Wiegand
Brigitte M. Jockusch
Ulrich Walter
eng
uncontrolled
cAMP / cGMP / cytoskeleton / phosphorylation / protein kinase
Biowissenschaften; Biologie
open_access
Theodor-Boveri-Institut für Biowissenschaften
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/3132/Scheer_Phosphorprotein_VASP.pdf
6945
1992
eng
article
1
2013-09-03
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In situ hybridization of DIG-labeled rRNA probes to mouse liver ultrathin sections
No abstract available.
8080
urn:nbn:de:bvb:20-opus-69458
In: Procedures for In Situ Hybridization to Chromosomes, Cells and Tissue Sections, 1992, 5, S. 148-151
Deutsches Urheberrecht
D. Fischer
D. Weisenberger
Ulrich Scheer
deu
swd
Hybridisierung <Biologie>
Biowissenschaften; Biologie
open_access
Theodor-Boveri-Institut für Biowissenschaften
Universität Würzburg
https://opus.bibliothek.uni-wuerzburg.de/files/6945/Scheer_6945.pdf