SNP-Targeting Oligonucleotides for Selective Allele Silencing
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Solution Overview
Problem
Current RNA silencing agents lack the ability to preferentially silence mutant, disease-causing alleles while minimizing the impact on wild-type alleles, leading to inefficient treatment of diseases caused by dominant mutations in heterozygotes.
Innovation Solution
Development of novel oligonucleotides, such as dsRNAs, that target single nucleotide polymorphisms (SNPs) with enhanced specificity, using mismatched positions to preferentially cleave SNP-containing targets over wild-type sequences, incorporating vinyl phosphonate modifications and specific seed region designs to achieve selective silencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If RNA silencing agents are designed to target mutant alleles, then silencing efficacy against mutant alleles is improved, but specificity relative to wild-type alleles deteriorates
Solution Approach 1:
The patent applies local quality by designing the RNA silencing agent with non-uniform nucleotide composition: positions 2-8 of the guide strand contain nucleotides complementary to the mutant allele sequence, while position 1 intentionally contains a mismatch relative to the wild-type allele. This localized differentiation at specific positions enables the agent to distinguish between mutant and wild-type alleles, achieving both high silencing efficacy against the mutant and high specificity by sparing the wild-type allele through the deliberate mismatch design
Solution Approach 2:
The patent employs parameter changes by systematically varying the nucleotide sequence parameters of the guide strand. Specifically, the nucleotide at position 1 is selected to create a mismatch with the wild-type allele while maintaining complementarity with the mutant allele. Additionally, nucleotides at positions 2-8 are optimized for mutant allele complementarity. These parameter variations in the sequence composition enable differential binding affinity, achieving preferential silencing of the mutant allele while preserving wild-type allele function
2Measurement precision
If RNA silencing agents are designed with high sequence specificity, then allele discrimination is improved, but silencing efficacy deteriorates
Solution Approach 1:
The patent applies local quality by concentrating the specificity-determining feature (the mismatch) at a localized position (position 1 of the guide strand) rather than distributing mismatches throughout the sequence. This localized mismatch design maintains strong complementarity at positions 2-8, ensuring high silencing efficacy against the mutant allele, while the localized mismatch at position 1 provides the discrimination capability needed to spare the wild-type allele
Solution Approach 2:
The patent applies partial action by introducing only a single mismatch at position 1 rather than multiple mismatches throughout the guide strand. This partial modification is sufficient to achieve wild-type allele discrimination while maintaining adequate complementarity (19-21 matching nucleotides out of 21 total) to ensure effective silencing of the mutant allele. The minimal mismatch approach balances discrimination capability with silencing efficacy
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
These oligonucleotides demonstrate up to 100-fold preferential silencing of mutant alleles compared to wild-type alleles, effectively treating diseases by selectively reducing mutant gene expression while sparing wild-type gene function.
Implementation Method 1
the oligonucleotide is complementary to a SNP position in a target nucleic acid
Implementation Method 2
RNA interference represents a simple and effective tool for inhibiting the function of genes
Data Source
AI summary
Novel oligonucleotides that enhance silencing of the expression of a gene containing a single nucleotide polymorphism (SNP) relative to the expression of the corresponding wild-type gene are provided. Methods of using novel oligonucleotides that enhance silencing of the expression of a gene containing a SNP relative to the expression of the corresponding wild-type gene are provided.