Blocking and Reporter Adapters for Sensitive Mutant Detection
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Solution Overview
Problem
Current methods for detecting genetic mutations in cancer and infectious diseases are complex and laborious, requiring multiple sequence-specific amplifications and have limited sensitivity, making it difficult to detect low-frequency mutants effectively.
Innovation Solution
The use of two ubiquitous adapters, a 'blocking adapter' and a 'reporter adapter,' along with Differential Sequence Fill-in (DSF) and single-strand-specific nuclease digestion, allows for the simultaneous detection of multiple genetic alterations by forming mutant-dual adapter hybrids, which can be easily amplified and quantified using universal primers, bypassing the need for multiple target-specific amplifications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sequence-specific amplifications are performed to ensure specificity of mutation detection, then measurement precision is improved, but device complexity and labor requirements increase significantly
Solution Approach 1:
The patent employs universal adapters (blocking adapter and reporter adapter) that can be used across multiple different genes and mutation types. These adapters perform multiple functions: they enable sequence-specific amplification through differential sequence fill-in, provide universal binding sites for PCR amplification, and allow detection of various mutations (point mutations, insertions, deletions) without requiring gene-specific adapter designs. This universal approach maintains measurement precision while reducing device complexity.
Solution Approach 2:
The blocking adapter serves as an intermediary element that mediates between the target DNA sequence and the detection system. It contains a blocked 3'-OH group that prevents extension unless a specific mutation is present, at which point differential sequence fill-in occurs. This intermediary mechanism enables specific mutation detection while using universal adapters that can be applied to multiple genes, thereby reducing overall system complexity.
2Measurement precision
If sensitivity is increased to detect low-frequency mutants, then measurement precision is improved, but device complexity and assay requirements become more stringent
Solution Approach 1:
The patent performs preliminary enrichment of mutant sequences before final detection through a process called pre-enrichment PCR. This preliminary action amplifies mutant-containing templates selectively, increasing their frequency in the sample population before the main detection assay. This allows detection of low-frequency mutants (as low as 0.1% or lower) while keeping the overall assay manageable in complexity.
Solution Approach 2:
The patent replaces complex mechanical separation and analysis methods with a biochemical amplification system. Instead of using sophisticated physical methods to isolate and detect rare mutants, the invention uses differential sequence fill-in and selective PCR amplification to biochemically enrich and amplify mutant sequences, making sensitive detection achievable with standard laboratory equipment and simpler assays.
3Productivity
If multiple genes are screened simultaneously to reduce screening time, then productivity is improved, but measurement precision and reliability may deteriorate
Solution Approach 1:
The universal adapter system enables simultaneous screening of multiple genes in a single reaction mixture. The blocking adapter and reporter adapter can be used with any target gene that contains the appropriate recognition sequence, allowing multiplexed analysis of multiple genes without requiring separate assays for each gene. This maintains measurement precision through the consistent use of universal adapter mechanisms while dramatically improving productivity through high-throughput capability.
Solution Approach 2:
The patent segments the detection process into distinct functional modules: (1) differential sequence fill-in step that identifies mutations, (2) blocking adapter ligation step that captures mutant sequences, (3) pre-enrichment PCR step that amplifies mutants selectively, and (4) final detection step that quantifies results. This segmentation allows each module to be optimized independently while working together in a coordinated manner, enabling accurate simultaneous screening of multiple genes through a standardized workflow.
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 enables sensitive detection and quantification of low-frequency mutants across multiple genes and samples, improving the sensitivity from approximately 1-10% to detecting mutants among hundreds of thousands of non-mutants, facilitating high-throughput mutation screening.
Implementation Method 1
sequential ligation of the blocking adapter and the reporter adapter is enabled by differential sequence fill-in (DSF)
Implementation Method 2
Mutants and homologous sequences that are not completely filled in with complementary dNTPs are digested into fragments by single-strand-specific nuclease
Implementation Method 3
sequential ligation of the blocking adapter and the reporter adapter is enabled by differential sequence fill-in (DSF) with a complementary deoxyribonucleotide triphosphate (dNTP)
Implementation Method 4
mutation detection may be easily augmented by polymerase chain reaction (PCR) with the use of just two ubiquitous primers
Data Source
AI summary
A kit to execute a method of simultaneously performing comparative transcript analysis in a multitude of samples. The kit includes a blocking adapter. The blocking adapter includes an inert 3′ end.