3-D organization of ribosomal transcription units after DRB inhibition of RNA polymerase II transcription
| Autor: | Sophie Le Panse, Jean-Marc Chassery, Laurent Héliot, Claude Masson, Henriette Roberte Junéra, Danièle Hernandez-Verdun |
|---|---|
| Rok vydání: | 1999 |
| Předmět: |
Dense fibrillar component
Transcription Genetic Nucleolus RNA polymerase II Biology DNA Ribosomal Cell Line chemistry.chemical_compound Transcription (biology) Animals Enzyme Inhibitors Gene Macropodidae Cell Biology Ribosomal RNA Molecular biology DNA-Binding Proteins Microscopy Electron Pol1 Transcription Initiation Complex Proteins chemistry biology.protein RNA Polymerase II Ribosomes DNA Cell Nucleolus Dichlororibofuranosylbenzimidazole Transcription Factors |
| Zdroj: | Journal of cell science. 112 |
| ISSN: | 0021-9533 |
| Popis: | In each bead of the nucleolar necklace, using adenosine analog DRB-treated PtK1 cells, we investigated the three components of rDNA transcription, i.e. the gene, transcription factor UBF and transcripts. In situ hybridization revealed the unraveling and 3-D dispersion of most of the rDNA coding sequences within the nucleus. The signals were small, of similar intensity and tandemly organized in the necklace. This observation is compatible with the fact that they might correspond to single gene units. Active transcription was visualized in these units, demonstrating that they were active functional units. Transcript labeling was not similar for each unit, contrary to UBF labeling. UBF and rRNA transcripts were only partially colocalized, as demonstrated by 3-D image analysis and quantification. As visualized by electron microscopy, the necklace was composed of a small fibrillar center partially surrounded by a dense fibrillar component. The 3-D arrangement of this individual unit in the necklace, investigated both by confocal and electron microscopy in the same cells, showed that the individual beads were linked by a dense fibrillar component. The reversibility of this organization after removal of DRB indicated that the beads in the necklace are certainly the elementary functional domain of the nucleolus. In addition, these results lead us to suggest that the organization of a functional domain, presumably corresponding to a single gene, can be studied by in situ approaches. |
| Databáze: | OpenAIRE |
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