Computational RNomics of drosophilids

Area of Science:

• Genomics
• Bioinformatics
• Evolutionary Biology

Background:

• Recent studies highlight numerous non-protein-coding transcripts.
• A subset of these RNAs requires specific secondary structures for function, showing conserved patterns indicative of positive selection.
• Comparative genomics offers a powerful approach to identify such evolutionarily conserved RNA motifs.

Purpose of the Study:

• To conduct a genome-wide survey to identify evolutionarily conserved RNA secondary structure motifs in the Drosophila genome.
• To leverage deep-sequencing data from multiple drosophilid species for comparative computational analysis.
• To investigate the functional implications of conserved RNA structures in non-coding regions.

Main Methods:

• Utilized the RNAz tool for a genome-wide survey of RNA secondary structures.
• Analyzed deep-sequencing data from 12 drosophilid species.
• Investigated RNAz predictions overlapping with known binding sites for transcription factors (e.g., TRF1, BRF) as potential Pol III transcripts.

Main Results:

• Identified over 16,000 high-quality RNA structure predictions, including most known small non-coding RNAs (ncRNAs).
• Estimated at least ten thousand loci in the Drosophila genome exhibit hallmarks of stabilizing selection on RNA structure, suggesting functional roles.
• Discovered clusters of ncRNA candidates with similar structures among potential Pol III transcripts.

Conclusions:

• Structured RNAs are found in introns, UTRs, and intergenic regions across Drosophila and vertebrate genomes.
• Intergenic RNA structures in flies are located closer to protein-coding loci compared to mammals.
• Flies appear to possess a smaller set of independent structured ncRNAs than mammals.