Omega Primer Design for Specific Short-Chain RNA Detection
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Solution Overview
Problem
Current methods for detecting short-chain RNAs, such as miRNAs, face challenges due to their short length, which makes it difficult to form stable primer-RNA duplexes, leading to issues with reverse transcription efficiency and specificity, particularly with conventional primers that suffer from internal initiation and primer dimerization.
Innovation Solution
The development of an oligonucleotide primer with an omega structure, featuring a 5′ to 3′ sequential design including a PCR primer target region, variable coding region, omega stem-loop, spacer region, and probe region, which provides thermostability and specificity by inhibiting internal initiation and primer dimerization, allowing for precise and multi-target detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional primers are used for detecting short-chain RNAs, then the detection method is simple, but the reverse transcription efficiency and specificity are poor due to internal initiation and primer dimerization
Solution Approach 1:
The primer is divided into multiple functional domains: a 5' domain for hybridization to the target RNA, a middle domain forming a stem-loop structure, and a 3' domain preventing internal initiation. This segmentation allows each domain to perform its specific function independently, improving overall reverse transcription specificity while managing structural complexity through modular design.
Solution Approach 2:
The primer contains a nested stem-loop structure where the middle domain forms a hairpin loop that is embedded within the overall primer structure. This nested configuration prevents the primer from forming dimers with itself or internally initiating, thereby improving reliability without requiring completely external control mechanisms.
2Stability of the object's composition
If the primer length is increased to improve Tm and stability, then the thermostability improves, but the primer becomes less suitable for short-chain RNA detection
Solution Approach 1:
The primer design concentrates stability-enhancing features in specific local regions: the stem-loop structure in the middle domain provides local thermostability through base pairing, while the 5' domain maintains optimal length for hybridization. This localized approach to stability allows the overall primer to remain appropriately sized for short-chain RNA detection while achieving sufficient Tm through strategic structural elements.
Solution Approach 2:
The primer combines different structural elements (single-stranded regions, stem-loop structures, and hybridization domains) to create a composite molecular structure. This composite design allows the primer to achieve thermostability through the stem-loop configuration rather than simply increasing overall length, enabling effective detection of short-chain RNAs with optimal binding stability.
3Measurement precision
If conventional PCR methods are used for miRNA detection, then the detection process is straightforward, but the accuracy is insufficient due to inability to prevent internal initiation
Solution Approach 1:
The primer's 3' domain is pre-configured with a sequence and structure that specifically prevents internal initiation before the PCR process begins. The stem-loop structure is formed during primer synthesis or initial denaturation, proactively blocking internal initiation sites before they can interfere with detection accuracy, thereby maintaining operational simplicity while improving precision.
Solution Approach 2:
The design converts the potential harm of internal initiation into a benefit by using the primer's own structure to block it. The 3' domain is specifically designed to form a stable structure that prevents the primer from binding to internal sites, transforming what would be a source of error into a feature that enhances detection accuracy without complicating the overall procedure.
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 omega primer design enhances reverse transcription specificity and sensitivity, enabling efficient detection of short-chain RNAs by preventing internal initiation and primer dimerization, allowing for higher throughput and accurate analysis of multiple targets.
Implementation Method 1
an omega stem-loop, wherein a stem length of the omega stem-loop is 4-12 bases in pair and has a cis-structure
Implementation Method 2
Through the base complementary process in the matching region, the primer and the RNA template can form a double-stranded complex, which is the necessary requirement for the start (trigger) of reverse transcript reaction
Data Source
AI summary
Disclosed are an oligonucleotide primer with an omega structure for detecting short-chain RNAs and the use thereof. The primer from the 5′ end to the 3′ end sequentially is: a PCR primer target region of 20-30 bases, a variable coding region of 0-50 bases, an omega stem-loop, a probe spacer of at least one base and a probe region of 4-11 bases. The length of the stem of the omega stem-loop is 4-12 paired bases, and the length of the loop of the omega stem-loop is 3-20 unpaired bases.