Non-isotopic mapping of ribosomal RNA synthesis and processing in the nucleolus
Language English Country Austria Media print-electronic
Document type Journal Article, Research Support, Non-U.S. Gov't
- MeSH
- Cell Nucleolus genetics metabolism ultrastructure MeSH
- Chromosomal Proteins, Non-Histone metabolism MeSH
- Fluorescent Antibody Technique, Direct MeSH
- Transcription, Genetic MeSH
- HeLa Cells MeSH
- In Situ Hybridization methods MeSH
- Microscopy, Immunoelectron MeSH
- Rabbits MeSH
- Humans MeSH
- Luminescent Proteins analysis MeSH
- Mice MeSH
- RNA Processing, Post-Transcriptional * MeSH
- RNA Precursors biosynthesis genetics metabolism MeSH
- RNA, Ribosomal biosynthesis genetics metabolism MeSH
- Green Fluorescent Proteins MeSH
- Animals MeSH
- Check Tag
- Rabbits MeSH
- Humans MeSH
- Mice MeSH
- Female MeSH
- Animals MeSH
- Publication type
- Journal Article MeSH
- Research Support, Non-U.S. Gov't MeSH
- Names of Substances
- Chromosomal Proteins, Non-Histone MeSH
- fibrillarin MeSH Browser
- Luminescent Proteins MeSH
- RNA Precursors MeSH
- RNA, Ribosomal MeSH
- Green Fluorescent Proteins MeSH
The precise location of ribosomal RNA (rRNA) synthesis within the nucleolus is the subject of recent controversy; some investigators have detected nascent RNA in the dense fibrillar components (DFCs) while others have localized transcription to the fibrillar centers (FCs). We endeavored to resolve this controversy by applying a new technique for non-isotopic labeling of RNA and examined the synthesis and movement of non-isotopically labeled rRNA within the nucleolus. We found that rRNA is synthesized only in a restricted area of DFCs, also involving the boundary region with FCs. We traced a movement of RNA from transcription sites through DFCs to granular components. Our results indicate functional compartmentalization of DFCs with respect to the synthesis and processing of precursor rRNA. In situ mapping of the 5' leader sequence of the 5' external transcribed spacer together with transcription labeling indicated that transcription and the first steps in processing of precursor rRNA are spatially separated. Surprisingly, the results also pointed to a partially extended conformation of newly synthesized precursor rRNA transcripts.
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