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Updated: Jan 6, 2026
A Rapid High-throughput Method for Mapping Ribonucleoproteins RNPs on Human pre-mRNA
Published on: December 2, 2009
Systematic mapping of small nucleolar RNA interactions in human cells
Hywel Dunn-Davies1, Tatiana Dudnakova1, Jean-Louis Langhendries2
1Centre for Cell Biology, School of Biological Sciences, University of Edinburgh, Edinburgh, UK.
Abstract:
Altered expression of box C/D small nucleolar RNAs (snoRNAs) is implicated in human diseases, including cancer. Box C/D snoRNAs canonically direct site-specific, 2'-O-methylation but the extent to which they participate in other functions remains unclear. To identify RNA interactions of box C/D snoRNAs in human cells, we applied two techniques based on UV crosslinking, proximity ligation and sequencing of RNA hybrids (CLASH and FLASH). These identified hundreds of novel snoRNA interactions with rRNA, snoRNAs and mRNAs. We developed an informatic pipeline to rigorously call interactions predicted to direct methylation. Multiple snoRNA-rRNA interactions identified were not predicted to direct RNA methylation. These potentially modulate methylation efficiency and/or contribute to folding dynamics during ribosomal subunit biogenesis. snoRNA-mRNA hybrids included 1,300 interactions between 117 snoRNA families and 940 mRNAs. Human U3 is substantially more abundant than other snoRNAs and represented about 50% of snoRNA-mRNA hybrids. The distribution of U3 interactions across mRNAs also differed from other snoRNAs. Following U3 depletion, mRNAs showing altered abundance were strongly enriched for U3 CLASH interactions. Most human snoRNAs are excised from pre-mRNA introns. Enrichment for snoRNA association with branch point regions of introns that contain snoRNA genes was common, suggesting widespread regulation of snoRNA maturation.
Insights
Small nucleolar RNAs (snoRNAs) interact with more RNAs than previously known, revealing novel roles beyond methylation in human cells. These findings expand our understanding of snoRNA functions in gene regulation and disease.
Area of Science:
- Molecular Biology
- Genetics
- Biochemistry
Background:
- Altered expression of box C/D small nucleolar RNAs (snoRNAs) is linked to human diseases like cancer.
- While canonically directing 2'-O-methylation, the full functional repertoire of snoRNAs remains largely unexplored.
Purpose of the Study:
- To comprehensively identify RNA interactions of box C/D snoRNAs in human cells.
- To explore novel functions of snoRNAs beyond their canonical role in RNA methylation.
Main Methods:
- Utilized UV crosslinking, proximity ligation, and sequencing of RNA hybrids (CLASH and FLASH) to map snoRNA interactions.
- Developed a bioinformatics pipeline for rigorous identification and analysis of snoRNA-RNA interactions.
- Performed U3 snoRNA depletion experiments to assess functional consequences of snoRNA-mRNA interactions.
Main Results:
- Identified hundreds of novel interactions between snoRNAs and rRNA, other snoRNAs, and mRNAs.
- Discovered numerous snoRNA-rRNA interactions not predicted to direct methylation, suggesting roles in ribosome biogenesis.
- Documented extensive snoRNA-mRNA interactions, with U3 snoRNA showing unique binding patterns and functional impact upon depletion.
- Observed enrichment of snoRNA association with intronic regions, indicating regulation of snoRNA maturation.
Conclusions:
- Box C/D snoRNAs engage in diverse RNA interactions, extending their known functions beyond methylation.
- These novel interactions may play significant roles in gene regulation, RNA processing, and cellular function.
- Findings provide a foundation for understanding snoRNA contributions to human health and disease.
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