Bacteria-Free Nanocircle Assembly for Eukaryotic Expression
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Solution Overview
Problem
Current commercial DNA assembly techniques are laborious and time-consuming due to their reliance on bacterial-dependent steps, requiring multiple additional steps and components, and there are no viable alternatives to E. coli or other bacterial-based methods for efficient transfer and expression of products in eukaryotic cells.
Innovation Solution
A bacteria-free method for assembling nucleic acid molecules into nanocircles, which can be directly transferred and expressed in eukaryotic cells, involving the joining of linear double-stranded nucleic acid molecules in a single reaction using a mixture of components including the nucleic acid molecules, a 5' to 3' exonuclease, a DNA ligase, and a buffer, without the need for bacterial transformation or propagation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If bacterial-dependent DNA assembly techniques are used, then reliable nucleic acid construction is achieved, but the process becomes laborious and time-consuming
Solution Approach 1:
The invention extracts and eliminates the bacterial amplification step from the DNA assembly process. By using a bacterial-free in vitro system with modified phosphodiester groups and specific exonucleases, the method achieves reliable circular DNA construction without requiring E. coli transformation, propagation, and plasmid extraction steps, thereby dramatically reducing preparation time while maintaining construction reliability
Solution Approach 2:
The invention replaces the biological bacterial system with an in vitro biochemical system. Instead of relying on bacterial enzymes and cellular machinery for DNA assembly and amplification, the method uses controlled in vitro reactions with purified enzymes (exonucleases, ligases) and modified nucleic acid substrates, substituting a mechanical/biochemical system for a biological one to eliminate time-consuming bacterial culture steps
2Productivity
If bacterial-based methods are used for DNA assembly, then efficient product transfer to eukaryotic cells is achieved, but multiple additional steps and components are required
Solution Approach 1:
The invention merges multiple separate bacterial-based steps into a single in vitro reaction. The assembly of linear DNA fragments into circular constructs, which traditionally required transformation, bacterial propagation, plasmid extraction, and purification, is accomplished in one streamlined in vitro procedure using modified phosphodiester groups and specific enzyme activities, thereby reducing device complexity while maintaining productivity
Solution Approach 2:
The in vitro system performs multiple functions that traditionally required separate bacterial steps. The modified phosphodiester groups enable both protection from exonuclease degradation and facilitation of circularization, while the in vitro reaction simultaneously achieves DNA assembly, amplification-free product generation, and direct transfection readiness, making the system universally applicable without bacterial components
3Quantity of substance
If bacterial amplification steps are used, then sufficient DNA yield is produced, but the need for endotoxin removal and additional purification steps increases
Solution Approach 1:
The invention extracts and eliminates the source of endotoxin contamination by removing the bacterial amplification step entirely. The in vitro system produces DNA yields sufficient for transfection without introducing bacterial endotoxins, thereby eliminating the need for endotoxin removal steps and additional purification procedures while maintaining adequate DNA quantity
Solution Approach 2:
The invention converts the potential harm of bacterial endotoxin contamination into a benefit by using a bacterial-free system. The modified phosphodiester groups, which initially seem like complex additions, actually simplify the overall process by enabling direct in vitro circularization without bacterial steps, thereby eliminating endotoxin issues and reducing total purification requirements
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 significantly reduces the time required for DNA preparation and expression in eukaryotic cells, eliminating the need for bacterial amplification and endotoxin removal, and achieves high transfection efficiency and expression of proteins and RNAs in human cells.
Implementation Method 1
a 5' to 3' exonuclease that lacks the 3' to 5' exonuclease activity and whose 5' to 3' exonuclease hydrolysis activity is reduced by the modified phosphodiester group
Implementation Method 2
a DNA ligase, and (d) a buffer suitable for joining ends of the said one or more linear double-stranded nucleic acid molecules using concomitant activity of the 5' to 3' exonuclease and the DNA ligase
Data Source
AI summary
This invention is directed to methods and compositions for bacteria-free preparation, assembly and expression of heterologous products in eukaryotic cells, including an in vitro method for joining ends of one or more linear double-stranded nucleic acid molecules to form a circular double-stranded nucleic acid construct for use in transfection, electroporation, nucleofection, and/or other form of delivery of the circular nucleic acid construct into a eukaryotic cell, as well as methods for making and compositions comprising the nucleic acid molecules and nucleic acid constructs for use in the methods disclosed herein.