References of "Lamaye, Françoise"
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See detailThe nucleolus: When 2 became 3.
Thiry, Marc ULg; Lamaye, Françoise ULg; Lafontaine, Denis L. J.

in Nucleus (2011), 2(4),

Though the nucleolus is considered today as a multifunctional domain, its primary function is ribosome biogenesis. We have shown at the ultrastructural level that there are primarily two types of ... [more ▼]

Though the nucleolus is considered today as a multifunctional domain, its primary function is ribosome biogenesis. We have shown at the ultrastructural level that there are primarily two types of nucleolar organization: nucleoli containing three components in amniotes and two components in all other eukaryotes. In a recent report we made the additional, and surprising, finding that both types of nucleolar arrangement are found among living reptiles, viz. a bicompartmentalized nucleolus in turtles and a tricompartmentalized nucleolus in lizards, crocodiles and snakes. This latter organization occurs regardless of the species, the tissue or the developmental stages analyzed. These results are compatible with the view that the transition between bipartite and tripartite nucleoli coincided with the emergence of the amniotes within the Reptilia. They also support the previous hypothesis that turtles are primitive reptiles. The emergence in amniote vertebrates of a third nucleolar compartment might have imparted novel regulatory functions to the nucleolus, as well as perhaps, expanding the adaptability of ribosome synthesis to an ever changing environment, thus, enhancing the overall fitness of amniotic vertebrates. [less ▲]

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See detailUltrastructural detection of nucleic acids within heat shock-induced perichromatin granules of HeLa cells by cytochemical and immunocytological methods.
Charlier, Christine; Lamaye, Françoise ULg; Thelen, Nicolas ULg et al

in Journal of Structural Biology (2009), 166(3), 329-36

The perichromatin granules (PGs) are enigmatic structures of the cell nucleus. The major drawbacks for a biological study are their rare occurrence and their small size in normal conditions. As heat shock ... [more ▼]

The perichromatin granules (PGs) are enigmatic structures of the cell nucleus. The major drawbacks for a biological study are their rare occurrence and their small size in normal conditions. As heat shock has been shown to increase their number, we applied a hyperthermal shock on HeLa cells to investigate the nucleic acid content of PGs by means of cytochemical and immunocytological approaches. These heat shock-induced PGs (hsiPGs) appeared as clusters organized in the form of honeycomb structures and were always associated with some blocks of condensed chromatin, such as the perinucleolar chromatin shell. A stalk connecting the hsiPG to the chromatin could be observed. For the detection of RNA, we applied an immunocytological method involving two anti-RNA antibodies and quantified the gold labelling obtained. The results clearly revealed that hsiPGs contained RNA. Regarding to the detection of DNA, we used three different methods followed by quantitative analyses. The results seemed to indicate that a small amount of DNA was present in hsiPGs. Together, these findings suggest that hsiPGs might be RNP structures associated with particular regions of DNA. [less ▲]

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See detailLocalization of Nopp140 within mammalian cells during interphase and mitosis.
Thiry, Marc ULg; Cheutin, Thierry; Lamaye, Françoise ULg et al

in Histochemistry & Cell Biology (2009), 132(2), 129-40

We investigated distribution of the nucleolar phosphoprotein Nopp140 within mammalian cells, using immunofluorescence confocal microscopy and immunoelectron microscopy. During interphase, three ... [more ▼]

We investigated distribution of the nucleolar phosphoprotein Nopp140 within mammalian cells, using immunofluorescence confocal microscopy and immunoelectron microscopy. During interphase, three-dimensional image reconstructions of confocal sections revealed that nucleolar labelling appeared as several tiny spheres organized in necklaces. Moreover, after an immunogold labelling procedure, gold particles were detected not only over the dense fibrillar component but also over the fibrillar centres of nucleoli in untreated and actinomycin D-treated cells. Labelling was also consistently present in Cajal bodies. After pulse-chase experiments with BrUTP, colocalization was more prominent after a 10- to 15-min chase than after a 5-min chase. During mitosis, confocal analysis indicated that Nopp140 organization was lost. The protein dispersed between and around the chromosomes in prophase. From prometaphase to telophase, it was also detected in numerous cytoplasmic nucleolus-derived foci. During telophase, it reappeared in the reforming nucleoli of daughter nuclei. This strongly suggests that Nopp140 could be a component implicated in the early steps of pre-rRNA processing. [less ▲]

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See detailA protocol for studying the kinetics of RNA within cultured cells: application to ribosomal RNA.
Thiry, Marc ULg; Lamaye, Françoise ULg; Thelen, Nicolas ULg et al

in Nature Protocols (2008), 3(12), 1997-2004

This protocol describes a nonisotopic method for high-resolution investigation of the kinetics of RNA within the cell. This involves the incorporation of bromouridine-5'-triphosphate into RNA of living ... [more ▼]

This protocol describes a nonisotopic method for high-resolution investigation of the kinetics of RNA within the cell. This involves the incorporation of bromouridine-5'-triphosphate into RNA of living cells by lipofection followed by immunocytological detection of BrRNAs. The use of the same antibody identified either with fluorescence or with gold particles revealed the three-dimensional organization of sites containing labeled RNAs or their precise localization by using confocal and ultrastructural microscopy, respectively. Comparison of three-dimensional reconstruction obtained from the series of optical sections and ultrathin sections was extremely fruitful to describe topological and spatial dynamics of RNAs from their synthesis site inside the nucleus to the cytoplasm. Combined with immunolocalization of proteins involved in different nuclear activities and with highly resolved three-dimensional visualizations of the labelings, this method should also provide a significant contribution to our understanding of the functional, volumic organization of the cell nucleus. The entire protocol can be completed in approximately 10 d. [less ▲]

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