Oligo-dT Blocking of PolyA-RNA Carrier in PCR
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Solution Overview
Problem
The use of polyA-RNA as a carrier in RNA isolation and reverse transcription can lead to high molecular weight products during PCR, which interfere with subsequent steps and reduce the yield of amplified target DNA due to unspecific hybridization with random hexamer primers.
Innovation Solution
Blocking polyA-RNA with oligo-dT molecules modified at the 3'-end with a phosphate and 1,3-propanediol spacer prevents hybridization with random hexamer primers, thereby preventing the formation of high molecular weight products during reverse transcription and PCR.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If polyA-RNA is used as carrier during RNA isolation, then RNA yield is increased, but high molecular weight products are generated during PCR which interfere with subsequent steps
Solution Approach 1:
The patent introduces oligo-dT molecules as an intermediary substance that specifically binds to polyA-RNA carrier molecules. This intermediary prevents direct hybridization between polyA-RNA and random hexamer primers, thereby eliminating the formation of high molecular weight products while preserving the beneficial effects of polyA-RNA on RNA yield
Solution Approach 2:
The patent applies preliminary anti-action by pre-incubating the sample with oligo-dT molecules before adding random hexamer primers. This preliminary binding of oligo-dT to polyA-RNA creates a protective effect that prevents the subsequent formation of harmful high molecular weight hybridization products during the PCR reaction
2Productivity
If polyA-RNA carrier is used with random hexamer primers, then RNA isolation efficiency is improved, but unspecific hybridization occurs leading to reduced target DNA amplification
Solution Approach 1:
Oligo-dT molecules serve as a mediator that selectively binds to polyA-RNA carrier, preventing it from participating in unspecific hybridization with random hexamer primers. This maintains the efficiency of RNA isolation while ensuring that only specific target DNA sequences are amplified during PCR
Solution Approach 2:
The patent effectively extracts or removes the harmful hybridization activity of polyA-RNA by introducing oligo-dT molecules that sequester the polyA-RNA. This separation allows the polyA-RNA to continue enhancing RNA isolation efficiency while being prevented from causing unspecific amplification
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 use of 3'-blocked oligo-dT molecules effectively reduces the generation of high molecular weight products, enhancing the yield and specificity of PCR products by preventing unspecific hybridization, as demonstrated by the comparison of PCR products with and without oligo-dT pretreatment.
Implementation Method 1
hybridization of the blocking nucleic acid to the carrier nucleic acid
Data Source
Figure 1~2
AI summary
During RNA isolation carrier nucleic acids such as polyA-RNA are used in order to increase the yield of the isolated RNA. The carrier nucleic acids may lead to high molecular weight products which may interfere in subsequent steps, such as reverse transcription, PCR and gel electrophoresis. The present invention therefore refers to a method and a kit for reverse transcription and the use of a blocking nucleic acid molecule for blocking the carrier polyA-RNA.