scholarly journals Electron tomography reveals changes in spatial distribution of UBTF1 and UBTF2 isoforms within nucleolar components during rRNA synthesis inhibition

2019 ◽  
Vol 208 (2) ◽  
pp. 191-204 ◽  
Author(s):  
Pavel Tchelidze ◽  
Hervé Kaplan ◽  
Christine Terryn ◽  
Nathalie Lalun ◽  
Dominique Ploton ◽  
...  
Keyword(s):  
Spatial Distribution ◽  
Electron Tomography ◽  
Rrna Synthesis ◽  
Synthesis Inhibition ◽  
Nucleolar Components

scholarly journals Control of rRNA synthesis: Effect of protein synthesis inhibition

FEBS Letters ◽  
1975 ◽  
Vol 54 (1) ◽  
pp. 26-29 ◽  
Author(s):  
M.T. Franze-Fernández ◽  
A.V. Fontanive-Sanguesa
Keyword(s):  
Protein Synthesis ◽  
Rrna Synthesis ◽  
Protein Synthesis Inhibition ◽  
Synthesis Inhibition

3D Imaging of Strengthening Particles in Cr-V-Mo (13HMF) Steel Using FIB/SEM Tomography

2012 ◽  
Vol 186 ◽  
pp. 41-44
Author(s):  
Władysław Osuch ◽  
Adam Kruk ◽  
Grzegorz Michta ◽  
Aleksandra Czyrska-Filemonowicz
Keyword(s):  
Spatial Distribution ◽  
3D Imaging ◽  
Electron Tomography ◽  
Electron Diffraction Analysis ◽  
Low Alloy Steel ◽  
Detailed Characterization ◽  
Transmission Electron ◽  
Strengthening Particles ◽  
Meso Scale

The electron tomography and transmission electron microscopy studies of the carbides in the 0.5Cr-0.5Mo-0.25V (13HMF) low-alloy steel after service during 160 000 h at 540 °C were carried out. Identification of the carbides was performed by means of electron diffraction analysis. Meso-scale tomography technique, mainly FIB/SEM tomography, was used for detailed characterization of spatial distribution and metrology of the carbides in 13HMF steel. The results achieved confirm the ability of FIB tomography to get 3D reconstruction of internal microstructure of steel as well as to obtain information about the shape and spatial distribution of carbides.

Three-dimensional organization of active rRNA genes within the nucleolus

2002 ◽  
Vol 115 (16) ◽  
pp. 3297-3307 ◽  
Author(s):  
Thierry Cheutin ◽  
Marie-Françoise O'Donohue ◽  
Adrien Beorchia ◽  
Marc Vandelaer ◽  
Hervé Kaplan ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Electron Tomography ◽  
Three Dimensional ◽  
Spatial Arrangement ◽  
Ultrastructural Level ◽  
Rna Polymerase I ◽  
Rrna Genes ◽  
Rrna Synthesis ◽  
Fibrillar Component ◽  
Polymerase I

In this work, we have localized transcribing rRNA genes at the ultrastructural level and described their three-dimensional organization within the nucleolus by electron tomography. Isolated nucleoli, which exhibit a reduced transcriptional rate, were used to determine the sites of initial BrUTP incorporation (i.e. rRNA synthesis by the transcriptional machinery). Using pulse-chase experiments with BrUTP and an elongation inhibitor,cordycepin, it was possible to precisely localize the initial sites of BrUTP incorporation. Our data show that BrUTP incorporation initially takes place in the fibrillar centers and that elongating rRNAs rapidly enter the surrounding dense fibrillar component. Furthermore, we investigated the spatial arrangement of RNA polymerase I molecules within the whole volume of the fibrillar centers. Electron tomography was performed on thick sections of cells that had been labeled with anti-RNA polymerase I antibodies prior to embedding. Detailed tomographic analyses revealed that RNA polymerase I molecules are mainly localized within discrete clusters. In each of them, RNA polymerase I molecules were grouped as several coils, 60 nm in diameter. Overall, these findings have allowed us to propose a model for the three-dimensional organization of transcribing rDNA genes within the nucleolus.

scholarly journals Mutations in nucleolar proteins lead to nucleolar accumulation of polyA+ RNA in Saccharomyces cerevisiae.

1995 ◽  
Vol 6 (9) ◽  
pp. 1103-1110 ◽  
Author(s):  
T Kadowaki ◽  
R Schneiter ◽  
M Hitomi ◽  
A M Tartakoff
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Rna Polymerase ◽  
Rna Polymerase I ◽  
Nucleolar Protein ◽  
Rrna Synthesis ◽  
Ribosomal Subunits ◽  
Nucleolar Proteins ◽  
Synthesis And Processing ◽  
Polymerase I ◽  
Nucleolar Components

Synthesis of mRNA and rRNA occur in the chromatin-rich nucleoplasm and the nucleolus, respectively. Nevertheless, we here report that a Saccharomyces cerevisiae gene, MTR3, previously implicated in mRNA transport, codes for a novel essential 28-kDa nucleolar protein. Moreover, in mtr3-1 the accumulated polyA+ RNA actually colocalizes with nucleolar antigens, the nucleolus becomes somewhat disorganized, and rRNA synthesis and processing are inhibited. A strain with a ts conditional mutation in RNA polymerase I also shows nucleolar accumulation of polyA+ RNA, whereas strains with mutations in the nucleolar protein Nop1p do not. Thus, in several mutant backgrounds, when mRNA cannot be exported i concentrates in the nucleolus. mRNA may normally encounter nucleolar components before export and proteins such as Mtr3p may be critical for export of both mRNA and ribosomal subunits.

scholarly journals Nucleolar sub-compartments in motion during rRNA synthesis inhibition: Contraction of nucleolar condensed chromatin and gathering of fibrillar centers are concomitant

PLoS ONE ◽  
2017 ◽  
Vol 12 (11) ◽  
pp. e0187977 ◽  
Author(s):  
Pavel Tchelidze ◽  
Aassif Benassarou ◽  
Hervé Kaplan ◽  
Marie-Françoise O’Donohue ◽  
Laurent Lucas ◽  
...  
Keyword(s):  
Condensed Chromatin ◽  
Rrna Synthesis ◽  
Synthesis Inhibition

scholarly journals Nucleolar Components Involved in Ribosome Biogenesis Cycle between the Nucleolus and Nucleoplasm in Interphase Cells

2001 ◽  
Vol 153 (1) ◽  
pp. 169-176 ◽  
Author(s):  
Danyang Chen ◽  
Sui Huang
Keyword(s):  
Ribosome Biogenesis ◽  
Dynamic Properties ◽  
Ribosomal Subunit ◽  
Selective Inhibition ◽  
Rrna Synthesis ◽  
Functional Roles ◽  
Binding Factor ◽  
Upstream Binding Factor ◽  
Polymerase I ◽  
Nucleolar Components

We examined the mobilities of nucleolar components that act at various steps of the ribosome biogenesis pathway. Fluorescence recovery after photobleaching (FRAP) and fluorescence loss in photobleaching (FLIP) analyses demonstrate that factors involved in rRNA transcription (upstream-binding factor [UBF]), processing (nucleolin, fibrillarin, and RNase MRP subunits, Rpp29), and ribosome assembly (B23) exchange rapidly between the nucleoplasm and nucleolus. In contrast, the mobilities of ribosomal subunit proteins (S5, L9) are much slower. Selective inhibition of RNA polymerase I transcription does not prevent the exchanges but influences the rates of exchange differentially for different nucleolar components. These findings suggest that the rapid exchange of nucleolar components between the nucleolus and nucleoplasm may represent a new level of regulation for rRNA synthesis. The different dynamic properties of proteins involved in different steps of ribosome biogenesis imply that the nucleolar association of these proteins is due to their specific functional roles rather than simply their specific nucleolar-targeting events.

scholarly journals Synthesis of Janus plasmonic–magnetic, star–sphere nanoparticles, and their application in SERS detection

2016 ◽  
Vol 191 ◽  
pp. 47-59 ◽  
Author(s):  
Javier Reguera ◽  
Dorleta Jiménez de Aberasturi ◽  
Naomi Winckelmans ◽  
Judith Langer ◽  
Sara Bals ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Spatial Distribution ◽  
Iron Oxide ◽  
Electron Tomography ◽  
Magnetic Star ◽  
Specific Interactions ◽  
Unique Combination ◽  
Clear Separation ◽  
Janus Nanoparticles ◽  
Sers Detection

Multicomponent nanoparticles are of particular interest due to a unique combination of properties at the nanoscale, which make them suitable for a wide variety of applications. Among them, Janus nanoparticles, presenting two distinct surface regions, can lead to specific interactions with interfaces, biomolecules, membranes etc. We report the synthesis of Janus nanoparticles comprising iron oxide nanospheres and gold nanostars, through two consecutive seed-mediated-growth steps. Electron tomography combining HAADF-STEM and EDX mapping has been performed to evaluate the spatial distribution of the two components of the nanoparticle, showing their clear separation in a Janus morphology. Additionally, SERS measurements assisted by magnetic separation were carried out to assess the application of combined plasmonic and magnetic properties for sensing.

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