Nested PCR Assay for Integrated Proviral Sequencing
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Solution Overview
Problem
Current methods fail to effectively amplify and characterize rare integrated viral nucleic acid in host genomes, such as HIV, to identify integration sites and determine the integrity and phylogenetic relationship of integrated proviruses.
Innovation Solution
The use of synthetic 71 base pair, partially-double stranded DNA oligonucleotides with a 3′dT overhang and 15 base pair antisense strands with 5′P and 3′ C3 spacers, which are ligated to genomic DNA for nested PCR reactions, allowing for near full-length proviral amplification and sequencing to detect and locate integrated viral nucleic acid.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional amplification methods are used to detect integrated viral nucleic acid, then the detection process is simple, but the sensitivity and specificity are insufficient to detect rare integrations (around 1 provirus in 1000 human genomes)
Solution Approach 1:
The detection method is divided into multiple sequential amplification stages (first amplification reaction followed by second amplification reaction), where each stage targets specific portions of the integrated provirus. This segmentation allows progressive enrichment of rare viral sequences from complex genomic background, achieving high sensitivity without requiring a single overly complex amplification step.
Solution Approach 2:
The patent employs nested PCR reactions where the second amplification reaction is performed on products from the first amplification reaction. This nested approach enables progressive enrichment of target sequences, where outer primers in the first reaction capture broader regions and inner primers in the second reaction focus on specific viral sequences, thereby achieving high specificity for rare integrated proviruses.
2Loss of information
If amplification methods provide sufficient host and proviral DNA sequence to identify integration sites, then the characterization is comprehensive, but the amplification efficiency for rare integrations is insufficient
Solution Approach 1:
The first amplification reaction serves as a preliminary enrichment step that captures both host and viral sequences at the integration site before the second amplification reaction. This preliminary action ensures that sufficient template material is available for subsequent specific amplification, preventing information loss while maintaining efficient amplification of rare targets.
Solution Approach 2:
The first amplification reaction acts as an intermediary step that bridges the gap between the rare integrated provirus in the complex genomic DNA and the specific second amplification reaction. This intermediary amplification enriches the template material, enabling the second reaction to efficiently amplify specific viral sequences with complete information about the integration site.
3Loss of information
If the assay can characterize integrated nucleic acid and identify its location, then the diagnostic information is complete, but the detection method becomes more complex
Solution Approach 1:
The assay is segmented into two distinct amplification reactions with different primer sets, where the first reaction captures integration site information and the second reaction characterizes the integrated provirus. This segmentation allows comprehensive information gathering while keeping each individual reaction relatively simple and manageable.
Solution Approach 2:
The first amplification reaction with viral-specific primers serves multiple functions: it amplifies viral sequences for characterization and simultaneously enriches integration site-containing fragments for the second reaction. This multi-functionality reduces overall assay complexity by combining information gathering steps into a single reaction rather than requiring separate steps.
Data Source
AI summary
Disclosed are synthetic 71 base pair, partially-double stranded DNA oligonucleotides and methods for their use in the amplification and identification or integrated proviral DNA.