Degradable dUMP outer primers in merged tandem (M/T)-nested PCR: low- and single-copy DNA target amplification

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Nested PCR requires sequential amplification for sensitivity and specificity.
• Residual outer primers can cause artifacts in subsequent PCR cycles.
• Developing methods to prevent primer-template interactions is crucial for accurate DNA amplification.

Purpose of the Study:

• To develop a novel PCR method to prevent primer-introduced artifacts.
• To enhance sensitivity and specificity in amplifying low-copy DNA templates.
• To apply this method for mutation detection in single cells.

Main Methods:

• Utilized dU-containing primers in the first PCR round.
• Employed uracil N-glycosylase (UNG) to degrade dU-primers and products.
• Merged single-tube PCR with dU primers and nested PCR using non-dU primers (M/T-nested PCR).
• Applied the method to detect HEXA gene exon 11 mutations.

Main Results:

• Successfully amplified specific targets from as few as three haploid genome equivalents.
• Achieved specific product amplification from single cells in 19 of 20 replicates.
• Demonstrated reliable distinction between mutant and wild-type HEXA gene fragments from single cells using heteroduplex mutational analysis.

Conclusions:

• The merged tandem-nested (M/T-nested) PCR method effectively eliminates primer-associated artifacts.
• This technique offers high sensitivity and specificity for amplifying single-cell DNA.
• M/T-nested PCR coupled with heteroduplex analysis is a reliable tool for single-cell mutation detection.