Isothermal DNA Amplification Using Inosine-Modified Primers
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Solution Overview
Problem
DNA amplification techniques often suffer from high background signals due to non-target or non-specific amplification reactions caused by contamination with unwanted nucleic acids, which can lead to false-positive diagnoses, especially when amplifying limited DNA quantities.
Innovation Solution
The use of exonuclease-resistant, inosine-containing primers in conjunction with an endonuclease that can nick inosine-containing strands, along with a 5'→3' exonuclease-deficient DNA polymerase, in a DNA amplification reaction mixture, where the primer solution is pre-treated to remove contaminating nucleic acids before amplification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional DNA amplification techniques are used, then amplification efficiency is high, but background signals increase due to non-specific amplification from contaminating nucleic acids
Solution Approach 1:
The patent applies preliminary action by pre-treating the primer solution with exonuclease to remove contaminating nucleic acids before the amplification reaction begins. This preventive measure eliminates the source of non-specific amplification products while preserving the ability to efficiently amplify target DNA sequences.
Solution Approach 2:
The patent modifies the primer structure locally by incorporating inosine residues at specific positions (particularly at the 3' end) to create exonuclease-resistant primers. This localized modification allows the primer to resist degradation by exonuclease while maintaining its ability to hybridize to target sequences and initiate amplification.
2Measurement precision
If amplification is performed on limited DNA quantities, then diagnostic sensitivity is improved, but false-positive results increase due to contamination
Solution Approach 1:
The patent applies preliminary action by pre-treating the primer solution with exonuclease to remove contaminating nucleic acids before the amplification reaction begins. This preventive measure eliminates the source of non-specific amplification products while preserving the ability to efficiently amplify target DNA sequences.
Solution Approach 2:
The patent uses exonuclease as an intermediary substance that selectively degrades contaminating nucleic acids in the primer solution before amplification. This intermediary enzyme acts as a filter to remove harmful contaminants while leaving the exonuclease-resistant, inosine-containing primers intact for subsequent amplification.
3Device complexity
If standard primers are used, then amplification reaction is simple, but non-specific amplification products are generated
Solution Approach 1:
The patent modifies the primer structure locally by incorporating inosine residues at specific positions (particularly at the 3' end) to create exonuclease-resistant primers. This localized modification allows the primer to resist degradation by exonuclease while maintaining its ability to hybridize to target sequences and initiate amplification.
Solution Approach 2:
The patent creates composite primers that combine standard nucleotide sequences with inosine residues. This composite structure provides dual functionality: the standard nucleotide portions enable specific hybridization to target sequences, while the inosine residues provide resistance to exonuclease degradation.
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 approach significantly reduces non-specific amplification products, enhancing the specificity and accuracy of DNA amplification, particularly when amplifying limited DNA quantities by effectively removing contaminating nucleic acids and minimizing false-positive results.
Implementation Method 1
treating the primer solution with an exonuclease to remove any contaminating nucleic acids
Implementation Method 2
an endonuclease that is capable of introducing a nick in a double-stranded DNA sequence
Implementation Method 3
a strand displacement DNA polymerase
Data Source
AI summary
Disclosed are methods and kits for endonuclease-assisted DNA amplification reaction using decontaminated primer solutions that are pre-treated with a nuclease. Nucleic acid amplification assays that employ nuclease-resistant, inosine-containing primers, endonuclease V enzymes to introduce a nick into a target DNA comprising at least one inosine, and a DNA polymerase to generate amplicons of a target DNA are also disclosed.