Maiser, Andreas and Dillinger, Stefan and Laengst, Gernot and Schermelleh, Lothar and Leonhardt, Heinrich and Nemeth, Attila (2020) Super-resolution in situ analysis of active ribosomal DNA chromatin organization in the nucleolus. SCIENTIFIC REPORTS, 10 (1): 7462. ISSN 2045-2322,
Full text not available from this repository. (Request a copy)Abstract
Ribosomal RNA (rRNA) transcription by RNA polymerase I (Pol I) is the first key step of ribosome biogenesis. While the molecular mechanisms of rRNA transcription regulation have been elucidated in great detail, the functional organization of the multicopy rRNA gene clusters (rDNA) in the nucleolus is less well understood. Here we apply super-resolution 3D structured illumination microscopy (3D-SIM) to investigate the spatial organization of transcriptionally competent active rDNA chromatin at size scales well below the diffraction limit by optical microscopy. We identify active rDNA chromatin units exhibiting uniformly ring-shaped conformations with diameters of similar to 240nm in mouse and similar to 170nm in human fibroblasts, consistent with rDNA looping. The active rDNA chromatin units are clearly separated from each other and from the surrounding areas of rRNA processing. Simultaneous imaging of all active genes bound by Pol I and the architectural chromatin protein Upstream Binding Transcription Factor (UBF) reveals a random spatial orientation of regular repeats of rDNA coding sequences within the nucleoli. These observations imply rDNA looping and exclude potential formation of systematic spatial assemblies of the well-ordered repetitive arrays of transcription units. Collectively, this study uncovers key features of the 3D organization of active rDNA chromatin units and their nucleolar clusters providing a spatial framework of nucleolar chromatin organization at unprecedented detail.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | TRANSCRIPTION FACTOR; COMPLETE SEQUENCE; MODEL; COLOCALIZATION; MICROSCOPY; DYNAMICS; REPEAT; MOUSE; CELLS; UBF; |
| Subjects: | 500 Science > 570 Life sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Biochemie III > Prof. Dr. Gernot Längst |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 24 Mar 2021 10:43 |
| Last Modified: | 24 Mar 2021 10:43 |
| URI: | https://pred.uni-regensburg.de/id/eprint/44604 |
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