A cluster of ribosome synthesis factors regulate pre-rRNA folding and 5.8S rRNA maturation by the Rat1 exonuclease
| Autor: | Elisabeth Petfalski, David Tollervey, Sander Granneman |
|---|---|
| Rok vydání: | 2011 |
| Předmět: |
Exonuclease
0303 health sciences General Immunology and Microbiology General Neuroscience Plasma protein binding Ribosomal RNA Biology Ribosome Molecular biology General Biochemistry Genetics and Molecular Biology Cell biology 03 medical and health sciences 0302 clinical medicine Ribosomal protein biology.protein Binding site Internal transcribed spacer RRNA processing Molecular Biology 030217 neurology & neurosurgery 030304 developmental biology |
| Zdroj: | The EMBO Journal. 30:4006-4019 |
| ISSN: | 0261-4189 |
| Popis: | The 5′-exonuclease Rat1 degrades pre-rRNA spacer fragments and processes the 5′-ends of the 5.8S and 25S rRNAs. UV crosslinking revealed multiple Rat1-binding sites across the pre-rRNA, consistent with its known functions. The major 5.8S 5′-end is generated by Rat1 digestion of the internal transcribed spacer 1 (ITS1) spacer from cleavage site A3. Processing from A3 requires the ‘A3-cluster' proteins, including Cic1, Erb1, Nop7, Nop12 and Nop15, which show interdependent pre-rRNA binding. Surprisingly, A3-cluster factors were not crosslinked close to site A3, but bound sites around the 5.8S 3′- and 25S 5′-regions, which are base paired in mature ribosomes, and in the ITS2 spacer that separates these rRNAs. In contrast, Nop4, a protein required for endonucleolytic cleavage in ITS1, binds the pre-rRNA near the 5′-end of 5.8S. ITS2 was reported to undergo structural remodelling. In vivo chemical probing indicates that A3-cluster binding is required for this reorganization, potentially regulating the timing of processing. We predict that Nop4 and the A3 cluster establish long-range interactions between the 5.8S and 25S rRNAs, which are subsequently maintained by ribosomal protein binding. |
| Databáze: | OpenAIRE |
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