Bisulfite pH Control for Nucleic Acid Modification and Detection
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Solution Overview
Problem
Current methods for detecting and quantifying pseudouridine and 5-hydroxymethylcytosine in nucleic acids are limited by low sensitivity, high false positives, and lack of stoichiometry, with no available antibody for pseudouridine and unstable azide-modified reagents.
Innovation Solution
Treatment of nucleic acid molecules with bisulfite at a pH between 6.5 and 8.0 modifies pseudouridine and 5-hydroxymethylcytosine without deaminating unmodified cytosines, allowing for detection and quantification through reverse transcription and sequencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional bisulfite treatment (pH < 6.5) is used to detect pseudouridine and 5-hydroxymethylcytosine, then modification of these nucleotides occurs, but deamination of unmodified cytosines also occurs causing false positives
Solution Approach 1:
The patent changes the pH parameter of bisulfite treatment from conventional acidic conditions (pH < 6.5) to neutral or slightly alkaline conditions (pH ≥ 6.5). This parameter change selectively modifies pseudouridine and 5-hydroxymethylcytosine while preventing deamination of unmodified cytosines, thereby eliminating false positives and improving detection specificity.
2Measurement precision
If azide-modified CMC is used to enrich Ψ-containing RNA fragments for sequencing, then more Ψ sites can be identified, but the method lacks stoichiometry at modified sites and the azide-modified CMC is not stable for storage
Solution Approach 1:
The patent employs bisulfite as a stable, easily stored reagent that can be used repeatedly without degradation. Unlike azide-modified CMC which is unstable and cannot be stored, bisulfite provides a reliable, cost-effective alternative that maintains reagent stability while enabling comprehensive Ψ site identification through the modified bisulfite treatment protocol.
3Measurement precision
If CMC is used to generate CMC-modified Ψ for detection, then pseudouridine can be detected, but RT stop signatures occur at highly modified Ψ sites reducing accuracy
Solution Approach 1:
The patent converts the harmful effect of bisulfite modification on reverse transcription into a beneficial detection signal. By using neutral/alkaline bisulfite treatment, the method creates a specific chemical modification pattern that enables detection of pseudouridine sites through sequencing, transforming the potential harm of RT stops into a useful detection mechanism for identifying modified sites.
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
This method enables comprehensive and quantitative modification and detection of pseudouridine and 5-hydroxymethylcytosine, overcoming the limitations of existing techniques by providing high sensitivity and specificity, and stable results.
Implementation Method 1
treatment with bisulfite at a pH between about 6.5 and about 8.0 modifies pseudouridine and 5-hydroxymethylcytosine without inducing deamination of unmodified cytosines
Implementation Method 2
allowing for detection and quantification through reverse transcription and sequencing
Data Source
AI summary
Aspects of the present disclosure are directed to methods and compositions for modification, detection, and quantification of pseudouridine and 5-hydroxymethylcytosine. Disclosed are methods for modification of pseudouridine and/or 5-hydroxymethylcytosine comprising bisulfite treatment under particular conditions. Further disclosed are compositions and kits comprising a bisulfite solution and instructions for use.