RNase H-dependent PCR (rhPCR): improved specificity and single nucleotide polymorphism detection using blocked...

Area of Science:

• Molecular Biology
• Biochemistry
• Genetics

Background:

• Polymerase Chain Reaction (PCR) is a cornerstone technique for nucleic acid detection in research and diagnostics.
• Suboptimal primer placement in PCR can lead to primer dimer formation and misamplification of homologous sequences, compromising specificity.

Purpose of the Study:

• To develop a modified PCR method that enhances specificity and reduces artifacts like primer dimers.
• To investigate the utility of Pyrococcus abyssi RNase H2 in a novel primer activation strategy for improved PCR performance.

Main Methods:

• Utilized blocked primers containing a single ribonucleotide residue, activated by Pyrococcus abyssi (P.a.) RNase H2 cleavage (rhPCR).
• Primer activation is dependent on hybridization to the target DNA sequence, occurring 5' to the RNA base.
• Assessed the impact of mismatches near the cleavage site on RNase H2 efficiency and overall assay specificity.

Main Results:

• Ribonucleotide-primed PCR (rhPCR) effectively eliminated primer dimer formation.
• rhPCR significantly reduced misamplification of closely related sequences due to sequence-specific primer activation.
• Mismatches near the RNA:DNA base pair decreased RNase H2 cleavage efficiency, further enhancing specificity.
• rhPCR demonstrated superior sensitivity compared to standard allele-specific PCR for single nucleotide polymorphism (SNP) detection.

Conclusions:

• rhPCR markedly improves PCR specificity by preventing primer dimers and off-target amplification.
• The enhanced specificity and sensitivity of rhPCR are valuable for challenging quantitative PCR (qPCR) applications.
• rhPCR shows significant utility in genotyping, high-level multiplex assays, and rare allele detection.