3' Branch Ligation for Mate-Pair Library Construction
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Solution Overview
Problem
Current methods for large-scale genomic sequence analysis face inefficiencies in generating libraries of nucleic acid targets, particularly in terms of cost and throughput, and require improvements in library construction efficiency and GC-rich sequence coverage.
Innovation Solution
The development of novel 3' branch ligation methods, where a double-stranded target polynucleotide with a 3'-hydroxyl group is ligated to a 3' branch adapter with a 5' blunt end and a non-ligatable 3' end, using conditions suitable for ligation, along with the use of PEG or SSB protein to enhance ligation efficiency, and the construction of mate pair polynucleotide libraries through controlled nick translation and primer extension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional library construction methods are used, then the process can be performed with standard protocols, but the efficiency is low and GC-rich sequence coverage is poor
Solution Approach 1:
The patent modifies ligation reaction parameters by adding PEG (polyethylene glycol) to change the physical-chemical environment of the reaction. This parameter change increases ligation efficiency specifically for GC-rich sequences by altering the reaction conditions to favor ligation at difficult-to-ligate sites, thereby resolving the contradiction between overall efficiency and GC-rich coverage
Solution Approach 2:
The patent introduces a specially designed adapter as an intermediary molecule that facilitates ligation at GC-rich regions. The adapter acts as a mediator between the DNA fragments and the ligase enzyme, enabling efficient ligation at sequences that are normally difficult to ligate, thus improving both productivity and reliability
2Quantity of substance
If more nucleic acid input is used, then library construction can proceed with sufficient material, but the cost and complexity increase
Solution Approach 1:
By changing the ligation reaction parameters (adding PEG, optimizing buffer conditions), the patent enables efficient library construction with reduced nucleic acid input. The modified reaction conditions increase the efficiency of each molecule utilized, allowing sufficient library production from smaller input amounts without increasing process complexity
Solution Approach 2:
The patent uses a multi-step ligation process with separate adapters ligated at different stages. This segmentation allows each ligation step to be optimized independently, reducing the total nucleic acid required while maintaining manageable process complexity through modular construction
3Ease of manufacture
If standard ligation conditions are used, then the protocol is simple and cost-effective, but ligation efficiency at difficult sites is low
Solution Approach 1:
The patent modifies ligation conditions by adding PEG to the reaction buffer, creating a more concentrated effective environment that enhances ligation efficiency. This parameter change maintains relative simplicity of the protocol while dramatically improving ligation efficiency at difficult sites including GC-rich regions
Solution Approach 2:
The specially designed adapter serves as an intermediary that bridges the gap between standard ligation conditions and efficient ligation at difficult sites. The adapter's structure and sequence are optimized to facilitate binding and ligation at GC-rich regions, maintaining protocol simplicity while enhancing productivity
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 approach increases the efficiency of library construction, reduces the amount of nucleic acid input required, and improves coverage of GC-rich sequences, enabling higher-quality sequencing data while reducing costs and simplifying the library construction process.
Implementation Method 1
the target polynucleotide is contacted with the 3' branch adapter polynucleotide in the presence of a ligase under conditions suitable for ligation at the ligation site of the 3'-hydroxyl group of the target polynucleotide and the 5'-phosphate of the 5' blunt end of the adapter
Implementation Method 2
the ligation conditions comprise an amount of PEG or SSB protein or a combination thereof that is effective to detectably increase ligation of the 3' branch adapter to the target polynucleotide at the ligation site
Data Source
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Figure 3~4
Figure 5A~6A
AI summary
The present invention provides a method for ligating an adapter to a target polynucleotide and methods of generating of mate-pair polynucleotide constructs that employ such a ligation method. Libraries and arrays comprising mate-pair polynucleotide constructs, and methods of sequencing libraries and arrays comprising mate-pair polynucleotide constructs, are also provided.