Transposon End Tagging for PCR-Free DNA Fragment Library Prep
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Solution Overview
Problem
Current methods for generating DNA fragment libraries for next-generation sequencing are inefficient, wasteful, and require specialized instruments, leading to loss of DNA and laborious, time-consuming procedures, and often result in non-representative tagged fragments.
Innovation Solution
The use of transposon compositions and transposases to fragment and tag DNA, allowing for the generation of tagged DNA fragments through in vitro transposition reactions, followed by nucleic acid modifying enzymes to create di-tagged fragments suitable for next-generation sequencing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If traditional methods (sonication, nebulization, enzymatic digestion) are used to fragment and tag DNA, then DNA fragments can be generated, but the process is wasteful, lossy, and requires specialized instruments
Solution Approach 1:
The patent replaces mechanical fragmentation methods (sonication, nebulization) with a biochemical transposition system. The transposase enzyme catalyzes the insertion of transposon ends into target DNA, fragmenting the DNA without mechanical force. This substitution eliminates the need for specialized mechanical instruments while reducing DNA loss through a gentler, more controlled biochemical process.
Solution Approach 2:
The patent introduces transposon end compositions as intermediary elements that facilitate DNA fragmentation and tagging. These transposon ends serve as mediators between the transposase enzyme and the target DNA, enabling efficient fragment generation with attached sequencing tags. The transposon ends are inserted into the DNA and processed by DNA polymerase to create the final tagged fragments, improving both efficiency and reducing loss compared to direct mechanical methods.
2Loss of time
If traditional fragmentation methods are used, then DNA can be fragmented, but the process is laborious and time-consuming
Solution Approach 1:
The patent merges multiple functions into a single transposition reaction: DNA fragmentation, end tagging with sequencing tags, and preparation of sequencing templates all occur simultaneously in one reaction. The transposase inserts transposon ends that contain both the fragmentation signal and the sequencing tag, eliminating the need for separate fragmentation and tagging steps. This integration dramatically reduces processing time and simplifies the overall workflow.
Solution Approach 2:
The transposon end compositions are pre-designed to contain both the transposition signal and the sequencing tag in a single molecule. This preliminary preparation of the tagging mechanism allows the actual DNA processing to occur rapidly in a single step, rather than requiring multiple sequential operations. The transposon ends are ready to immediately fragment and tag DNA upon addition of the transposase.
3Manufacturing precision
If traditional methods are used, then DNA fragments can be generated, but the fragments are often non-representative
Solution Approach 1:
The patent changes the biochemical parameters of the fragmentation process by using a enzymatic transposition mechanism with controlled insertion kinetics. The transposase enzyme provides uniform, controlled fragmentation through its catalytic action, creating representative fragments that accurately reflect the original DNA composition. This biochemical control ensures consistent fragment size distribution and representativeness, improving sequencing accuracy compared to random mechanical fragmentation.
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 method efficiently generates representative DNA fragments with tags for next-generation sequencing, reducing the need for specialized instruments and minimizing DNA loss, while being faster and requiring smaller sample sizes.
Implementation Method 1
incubating the target DNA with a transposase and a transposon end or transposon end composition comprising a transferred strand that has a tag domain in its 5' portion, under conditions wherein a transposition reaction is catalyzed by the transposase
Implementation Method 2
incubating the 5'-tagged DNA fragments with a nucleic acid modifying enzyme under conditions wherein the strand displacement activity of the nucleic acid modifying enzyme joins the complement of the transferred strand to the 5'-tagged DNA fragments
Data Source
AI summary
The present invention provides methods, compositions and kits for using a transposase and a transposon end for generating extensive fragmentation and 5′-tagging of double-stranded target DNA in vitro, then using a DNA polymerase for generating 5′- and 3′-tagged single-stranded DNA fragments without performing a PCR amplification reaction, wherein the first tag on 5′-ends exhibits the sequence of the transferred transposon end and optionally, an additional arbitrary sequence, and the second tag on 3′-ends exhibits a different sequence from the sequence exhibited by the first tag. The method is useful for generating 5′- and 3′-tagged DNA fragments for use in a variety of processes, including processes for metagenomic analysis of DNA in environmental samples, copy number variation (CNV) analysis of DNA, and comparative genomic sequencing (CGS), including massively parallel DNA sequencing (so-called “next generation sequencing”).