Dominique Ploton

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The argyrophilic proteins of the nucleolar organizer region (Ag-NOR proteins) were specifically localized at the optical level with a modified one-step silver technique performed at 20° C. This method was applied to various materials including cells in smears, chromosomes, semi-thin sections of plastic-embedded cells and sections of paraffin-embedded human(More)
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(More)
Deletion of the amino acid residue Phe 508 of the cystic fibrosis transmembrane conductance regulator (CFTR) protein represents the most common mutation identified in cystic fibrosis (CF) patients. A monoclonal and a polyclonal antibody directed against different regions of CFTR were used to localize the CFTR protein in normal and CF airway epithelium(More)
Nucleoli with a thread-like fibrillar structure found in several human breast cancer cells were investigated for the localization of Ag-NOR proteins, RNA, DNA and associated nucleoproteins. Various cytochemical techniques were applied: the one-step silver method for Ag-NOR proteins, the Bernhard's staining preferential for RNP, the Feulgen-like(More)
Although rRNA synthesis, maturation, and assembly into preribosomal particles occur within the nucleolus, the route taken by pre-rRNAs from their synthetic sites toward the cytoplasm remains largely unexplored. Here, we employed a nondestructive method for the incorporation of BrUTP into the RNA of living cells. By using pulse-chase experiments,(More)
We have used the highly sensitive in situ terminal deoxynucleotidyl transferase method, applied to ultrathin sections, to investigate the location of DNA within nucleoli of various animal cells. In all the nucleoli studied, intense labelling is revealed over the peri-and intranucleolar condensed chromatin. Gold particles are also consistently found over the(More)
Data on the in situ structural-functional organization of ribosomal genes in the mammalian cell nucleolus are reviewed here. Major findings on chromatin structure in situ come from investigations carried out using the Feulgen-like osmium ammine reaction as a highly specific electron-opaque DNA tracer. Intranucleolar chromatin shows three different levels of(More)
The aim of the present work was to study the distribution and the behaviour of the silver-staining nucleolar organizer region (Ag-NOR) proteins at the ultrastructural level during interphase and mitosis in five human and murine cancerous cell lines each characterized by a typical nucleolar morphology. During interphase the Ag-NOR proteins are restricted to(More)