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Single Nucleotide Polymorphism-sensitive FISH Detection of Locus-specific Ribosomal RNA Transcription in Drosophila melanogaster
Published on: March 28, 2025
Two different chromatin structures coexist in ribosomal RNA genes throughout the cell cycle
A Conconi1, R M Widmer, T Koller
1Institute for Cell Biology, Swiss Federal Institute of Technology, Zürich.
Cell
|June 2, 1989
Summary
Friend cells exhibit two distinct ribosomal chromatin structures: nucleosome-containing inactive copies and non-nucleosomal active genes. These states are maintained independently of transcription and propagate through the cell cycle.
Area of Science:
- Molecular Biology
- Cell Biology
- Genetics
Background:
- Ribosomal chromatin structure is crucial for gene regulation.
- Understanding chromatin states in different cell cycle phases is essential.
Purpose of the Study:
- To investigate the structural organization of ribosomal chromatin in Friend cells.
- To determine if distinct chromatin structures correlate with transcriptional activity.
- To assess the stability of these structures throughout the cell cycle.
Main Methods:
- Psoralen photocrosslinking was employed to analyze ribosomal chromatin structure.
- Chromatin was examined in exponentially growing cells, stationary cells, and metaphase chromosomes.
Main Results:
- Two distinct ribosomal chromatin types were identified: nucleosome-containing (inactive) and lacking repeating structure (transcribed).
- Individual gene copies exist in either the active or inactive state.
- The relative proportions of these states remain consistent across interphase and metaphase, but their transcriptional activities vary.
Conclusions:
- Ribosomal chromatin exists in at least two stable states, independent of ongoing transcription.
- These chromatin states are stably maintained and propagated through the cell cycle.
- This suggests a mechanism for maintaining distinct chromatin conformations irrespective of gene expression levels.
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