Two-Stage Flap Cleavage Assay for Real-Time Point Mutation Detection
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Solution Overview
Problem
Existing methods for detecting point mutations in nucleic acids, such as those associated with diseases like Noonan syndrome and cancer, lack efficient and sensitive real-time detection and quantification capabilities.
Innovation Solution
A cleavage-based real-time PCR assay method involving two sets of thermocycling conditions is employed, where a reaction mixture containing PCR reagents and flap cleavage reagents is subjected to specific temperature cycles, allowing for real-time measurement of flap probe cleavage without additional reagents between cycles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional mutation detection methods are used, then detection capability is provided, but sensitivity and specificity for real-time detection are insufficient
Solution Approach 1:
The patent combines PCR amplification and flap endonuclease-based mutation detection into a single real-time assay system. The flap probe and FRET cassette are integrated into the PCR reaction mixture, allowing simultaneous amplification and detection without separate steps, thereby achieving both high sensitivity and real-time capability
Solution Approach 2:
The patent employs FRET (Fluorescence Resonance Energy Transfer) technology where fluorophore-labeled flap probes emit different fluorescence signals upon cleavage. The change in fluorescence intensity or wavelength indicates mutation presence, enabling real-time detection with high sensitivity through optical signal changes
2Measurement precision
If additional reagents are added between PCR and cleavage steps, then detection accuracy improves, but assay complexity and time increase
Solution Approach 1:
The patent merges the PCR amplification reagents and flap cleavage reagents into a single combined reaction mixture. The flap probe and FRET cassette are included in the initial reaction setup, eliminating the need for separate reagent additions between amplification and detection steps, thus reducing procedural complexity while maintaining detection accuracy
Solution Approach 2:
The reaction mixture serves multiple functions simultaneously: it performs PCR amplification of target DNA and enables flap endonuclease-based mutation detection. The same mixture supports both nucleic acid synthesis and specific cleavage reactions, reducing the number of separate steps and reagent additions required
3Productivity
If single-stage thermocycling is used, then assay simplicity is maintained, but detection resolution for low-abundance mutations is insufficient
Solution Approach 1:
The patent divides the thermocycling process into two distinct stages: a first stage with initial thermocycling conditions for amplification, and a second stage with modified thermocycling conditions optimized for flap probe cleavage and detection. This segmentation allows each stage to be optimized for its specific function, improving detection resolution for low-abundance mutations while maintaining overall assay efficiency
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
The method provides enhanced sensitivity and specificity in detecting and quantifying point mutations, enabling accurate diagnosis and analysis of diseases associated with such mutations.
Implementation Method 1
flap cleavage reagents for performing a flap cleavage assay on the amplified nucleic acid target
Implementation Method 2
subjecting a reaction mixture comprising a) PCR reagents for amplifying a nucleic acid target to two sets of thermocycling conditions
Implementation Method 3
the flap is labeled with a fluorescent label or other detectable group
Data Source
AI summary
A cleavage-based real-time PCR assay method is provided. In general terms, the assay method includes subjecting a reaction mixture comprising a) PCR reagents for amplifying a nucleic acid target, and b) flap cleavage reagents for performing a flap cleavage assay on the amplified nucleic acid target to two sets of thermocycling conditions. No additional reagents are added to the reaction between said first and second sets of cycles and, in each cycle of the second set of cycles, cleavage of a flap probe is measured.