References of "Thelen, Nicolas"
     in
Bookmark and Share    
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 25 (5 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 25 (9 ULg)
Full Text
Peer Reviewed
See detailEarly identification of inner pillar cells during rat cochlear development.
Thelen, Nicolas ULg; Breuskin, Ingrid ULg; Malgrange, Brigitte ULg et al

in Cell & Tissue Research (2009), 337(1), 1-14

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far from being elucidated. Here, we examine its spatio-temporal development ... [more ▼]

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far from being elucidated. Here, we examine its spatio-temporal development in rats from embryonic day 16 (E16) to E19 by using cytochemical and immunocytochemical methods at the light- and electron-microscope levels. We demonstrate that the organ of Corti develops from a non-proliferating cell zone that is located in the junctional region between two edges of the dorsal epithelium of the cochlear duct. We also reveal that the first cells to develop in this zone are the inner pillar cells, a particular type of non-sensory supporting cell, which arise in the base of the cochlear duct at the boundary between the two ridges at E16. Cell differentiation in this prosensory region continues according to a base-to-apex gradient; the inner hair cells appear in the greater epithelial ridge at E17 and the outer hair cells in the lesser epithelial ridge at E18. At E19, the various cell types of the organ of Corti are in place. Finally, we show that unlike the development of all the supporting cell types of the organ of Corti, the development of inner pillar cells within the prosensory domain seems not to involve Notch1 activation. These results highlight the central role that the inner pillar cells probably play in the development of the organ of Corti. [less ▲]

Detailed reference viewed: 42 (10 ULg)
Full Text
See detailSpatiotemporal Distribution of Polysaccharides During the Mammalian Auditory Organ Development
Thelen, Nicolas ULg; Compère, Philippe; Malgrange, Brigitte et al

Poster (2008, October 31)

Detailed reference viewed: 4 (1 ULg)
See detailNew insights in mammalian auditory organ development
Thelen, Nicolas ULg; Malgrange, Brigitte ULg; Thiry, Marc

Conference (2008, October 30)

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far from being elucidated. Using cytochemical and immunohistochemical methods ... [more ▼]

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far from being elucidated. Using cytochemical and immunohistochemical methods at the light and electron microscope levels, we examined its spatiotemporal development in rats from embryonic day 16 (E16) to E19. At E16, whatever the region of the cochlear studied (base, middle, apex), the organ of Corti was not present. We demonstrate that the organ of Corti develops from a non-proliferative cell zone that is located in the junctional region between the greater epithelial ridge and the lesser epithelial ridge of the cochlear duct and that is characterized by the presence of numerous microvilli. Using the periodic acid-thiocarbohydrazide-silver proteinate method, we revealed that the first cells to develop in this zone are the inner pillar cells, a particular type of nonsensory supporting cells. They arise in the base of the cochlear duct at the boundary between the two ridges at E16. The cell differentiation in this prosensory region continues according to a base-to-apex gradient, the inner hair cells appearing in the greater epithelial ridge at E17 and the outer hair cells in the lesser epithelial ridge at E18. At E19, all the different cell types of the organ of Corti are well in place. We also showed that the development of the inner pillar cells within the prosensory region does not involve Notch1 signaling. These results highlight the central role that the inner pillar cells could play in the development of the organ of Corti. [less ▲]

Detailed reference viewed: 12 (3 ULg)
Full Text
Peer Reviewed
See detailStrategies to Regenerate Hair Cells: Identification of Progenitors and Critical Genes
Breuskin, Ingrid ULg; Bodson, Morgan ULg; Thelen, Nicolas ULg et al

in Hearing Research (2008), 236(1-2), 1-10

Deafness commonly results from a lesion of the sensory cells and/or of the neurons of the auditory part of the inner ear. There are currently no treatments designed to halt or reverse the progression of ... [more ▼]

Deafness commonly results from a lesion of the sensory cells and/or of the neurons of the auditory part of the inner ear. There are currently no treatments designed to halt or reverse the progression of hearing loss. A key goal in developing therapy for sensorineural deafness is the identification of strategies to replace lost hair cells. In amphibians and birds, a spontaneous post-injury regeneration of all inner ear sensory hair cells occurs. In contrast, in the mammalian cochlea, hair cells are only produced during embryogenesis. Many studies have been carried out in order to demonstrate the persistence of endogenous progenitors. The present review is first focused on the occurrence of spontaneous supernumerary hair cells and on nestin positive precursors found in the organ of Corti. A second approach to regenerating hair cells would be to find genes essential for their differentiation. This review will also focus on critical genes for embryonic hair cell formation such as the cell cycle related proteins, the Atoh1 gene and the Notch signaling pathway. Understanding mechanisms that underlie hair cell production is an essential prerequisite to defining therapeutic strategies to regenerate hair cells in the mature inner ear. [less ▲]

Detailed reference viewed: 92 (31 ULg)
Full Text
See detailSox10 is not necessary for auditory neurons survival
Breuskin, I; Bodson, M; Thelen, Nicolas ULg et al

Poster (2008)

Detailed reference viewed: 5 (0 ULg)
Full Text
Peer Reviewed
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 ▲]

Detailed reference viewed: 49 (17 ULg)
See detailAn atypical cell during development of the auditory organ : the inner pillar cell
Thelen, Nicolas ULg; Malgrange, Brigitte ULg; Thiry, Marc ULg

Poster (2007, September)

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far to be elucidated. Using cytochemical and immunohistochemical methods at ... [more ▼]

Although the structure of the auditory organ in mature mammals, the organ of Corti, is clearly established, its development is far to be elucidated. Using cytochemical and immunohistochemical methods at the light and electron microscope levels, we examined its spatiotemporal development in rats from embryonic day 16 (E16) to E19. <br />At E16, whatever the region of the cochlear studied (base, middle, apex), the organ of Corti is not present. We demonstrate that the organ of Corti develops from a non-proliferative cell zone that is located in the junctional region between the greater epithelial ridge and the lesser epithelial ridge of the cochlear duct and that is characterized by the presence of numerous microvilli. Using the periodic acid-thiocarbohydrazide-silver proteinate method, we reveal that the first cells to develop in this zone are the inner pillar cells, a particular type of nonsensory supporting cells; they arise in the base of the cochlear duct at the boundary between the two ridges at E16. The cell differentiation in this prosensory region continues according to a base-to-apex gradient, the inner hair cells appear in the greater epithelial ridge at E17 and the outer hair cells in the lesser epithelial ridge at E18. At E19, all the different cell types of the organ of Corti are well in place. We also show that the development of the inner pillar cells within the prosensory region does not involve Notch1 signaling. These results highlight the central role that cells could play the inner pillar in the organ of Corti development. [less ▲]

Detailed reference viewed: 17 (2 ULg)
Full Text
See detailAn unusual cell type of the auditory organ during neonatal development: the inner pillar cells
Thelen, Nicolas ULg; Breuskin, I; Malgrange, B et al

Poster (2007)

Detailed reference viewed: 4 (0 ULg)
See detailSox 10 is not necessary for auditory neurons survival
Breuskin, I; Bodson, M; Thelen, Nicolas ULg et al

Poster (2007)

Detailed reference viewed: 5 (0 ULg)
Full Text
See detailSpatial dynamics of rRNAs within the cell nucleus
Thiry, Marc ULg; Lamaye, Françoise; Thelen, Nicolas ULg et al

Poster (2007)

Detailed reference viewed: 6 (2 ULg)
See detailRole of Sox 10 in the development of the inner ear
Bodson, M; Breuskin, I; Thelen, Nicolas ULg et al

Poster (2007)

Detailed reference viewed: 9 (0 ULg)
See detailPrenatal development study of rat corti organ at the morphological level
Thelen, Nicolas ULg; Malgrange, Brigitte ULg; Thiry, Marc ULg

Poster (2006, September)

Although the structural organization of the mature Corti organ is generally well defined, little is known about its prenatal development. Here, we have examined by photonic and electron transmission ... [more ▼]

Although the structural organization of the mature Corti organ is generally well defined, little is known about its prenatal development. Here, we have examined by photonic and electron transmission microscopies the morphological changes occurring in the cochlear epithelium from the embryonic day 16 to 19 in rat. Moreover, we have used the periodic acid-thiocarbohydrazide-silver proteinate method to detect the glycogen particles on semithin and ultrathin sections of the cochlear duct. <br />At the embryonic day 16 (E16), whatever the region of the cochlear studied (base, medium, apex), the organ of Corti is not present. The cochlear epithelium appears as a pseudostratified epithelium formed formed by two distinct regions according to the presence or the absence of microvilli at the apical surface of cells. The region with the microvilli is on the modiolar side and the presence of microvilli is a characteristic of cells in the greater epithelial ridge (GER). In basal part of the cochlear duct, glycogen particles are visible on ultrathin sections in only one cell. On both sides of this cell, apical part of the epithelium shows microvilli. At E17, on semithin sections of basal and medium parts of cochlear duct, one cell visible on the whole height of the epithelium shows rich content in glycogen . At E18, in the majority of sections realized at the base and medium of the cochlear canal, the organ of Corti is relatively well recognizable. We distinguish principally the inner hair cells but also to a lesser extent the outer hair cells as well as the supporting cells (pillar, phalengeal and Deiters cells).We show that only the pillar cells have a rich content in glycogen. At E19, the organ of Corti is clearly recognizable in all the basal and medium parts of the cochlear duct. By contrast, it is yet differenciated in the apex. <br />These data seem to indicate that the Corti organ in rat develops from base to apex in the greater epithelial ridge starting by the pillar cells. [less ▲]

Detailed reference viewed: 10 (5 ULg)
See detailRole of Sox 10 in the development of the inner ear
Bodson, M; Breuskin, I; Thelen, Nicolas ULg et al

Poster (2006)

Detailed reference viewed: 6 (2 ULg)
See detailSox 10 is not necessary for auditory neurons survival
Breuskin, I; Bodson; Thelen, Nicolas ULg et al

Poster (2006)

Detailed reference viewed: 3 (0 ULg)
See detailRole of Sox 10 in the development of the inner ear
Bodson, M; Breuskin, I; Thelen, Nicolas ULg et al

Poster (2006)

Detailed reference viewed: 7 (0 ULg)