Guidelines for antisense oligonucleotide design and insight into splice-modulating mechanisms

Area of Science:

• Molecular Biology
• Genetics
• Biotechnology

Background:

• Antisense oligonucleotides (AONs) are tools for modulating gene expression by targeting mRNA.
• AONs can influence mRNA processing, including splicing, through various mechanisms.
• The efficacy of AONs depends on factors like sequence, structure, and target accessibility.

Purpose of the Study:

• To retrospectively analyze factors influencing the effectiveness of AONs for dystrophin splice modulation.
• To identify key parameters for optimizing the design of splice-modulating AONs.
• To gain deeper insight into the mechanism of antisense-mediated exon skipping.

Main Methods:

• Retrospective analysis of 156 previously designed and evaluated AONs for dystrophin transcript splice modulation.
• Statistical comparison of sequence content, binding energies, and location relative to splice sites for effective versus ineffective AONs.
• Utilized ESE prediction software to analyze AON enrichment for exonic splicing enhancer sites.

Main Results:

• Effective AONs exhibited significantly higher guanine-cytosine content and binding energies (AON-target, AON-AON) compared to ineffective ones.
• Effective AONs were located significantly closer to the acceptor splice site.
• Effective AONs were enriched for predicted exonic splicing enhancers (ESEs), with an exception for Tra2beta binding sites found in ineffective AONs.

Conclusions:

• Higher GC content, stronger binding energies, and proximity to the splice acceptor site are key characteristics of effective splice-modulating AONs.
• ESE enrichment, particularly excluding Tra2beta sites, is indicative of effective AONs for exon skipping.
• A predictive model using four parameters achieved 79% accuracy in classifying AON effectiveness, aiding in optimal AON design.