Solid Phase TALE Assembly via Magnetic Bead Anchoring

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Solution Overview

Problem

Current methods for assembling TALE DNA binding domains are hindered by the need for intermediate amplification steps, high plasmid complexity, and decreased plating efficiency with increasing module numbers, limiting high-throughput and automation potential.

Innovation Solution

A method involving sequential assembly of TALE repeat modules on a solid phase using Type IIS restriction sites and enzymes, anchoring DNA fragments to facilitate easy removal of excess reactants and enzymes, eliminating the need for intermediate amplification and reducing plasmid complexity, allowing for high-throughput production on a 96-well plate format.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If intermediate amplification steps are used in TALE repeat module assembly, then assembly completeness can be verified, but the process complexity increases and automation potential is limited

Engineering Contradiction:
Improveassembly verificationVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the verification step from the amplification process by using solid phase anchoring with magnetic beads. The DNA fragments are captured directly on the magnetic bead surface through biotin-streptavidin interaction, allowing verification without intermediate amplification steps. This eliminates the need for multiple plasmid constructions and colony PCR screening while maintaining reliable verification of assembly completeness.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces magnetic beads coated with streptavidin as an intermediary carrier. These beads serve as a solid phase that anchors biotinylated DNA fragments, enabling direct visualization and verification of assembly products without requiring intermediate amplification. The magnetic beads act as a mediator that simplifies the verification process while maintaining reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If multiple plasmids are used for TALE repeat module assembly, then complete assembly can be achieved, but the number of required plasmids increases process complexity

Engineering Contradiction:
Improveassembly completenessVSAvoidplasmid complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent segments the TALE repeat modules into individual biotinylated DNA fragments that can be directly assembled on the solid phase. Each repeat module is designed with specific Type IIS restriction sites that allow directional cloning without requiring multiple intermediate plasmids. The segmentation is achieved through modular DNA fragment design rather than multiple plasmid constructions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent creates a universal assembly platform using Type IIS restriction sites (BbvI and SfaNI) that can accommodate any TALE repeat module sequence. The magnetic bead-based solid phase serves as a universal carrier for all DNA fragments, eliminating the need for multiple specialized plasmids. This universal system simplifies the overall process while maintaining the ability to assemble complete TALE arrays.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If traditional liquid-phase assembly is used, then flexibility in assembly is maintained, but removal of excess reactants and enzymes becomes difficult

Engineering Contradiction:
Improveassembly flexibilityVSAvoidreactant removal
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent transitions from liquid-phase assembly to solid-phase assembly by anchoring DNA fragments to magnetic beads. This dimensional change from 3D liquid solution to 2D solid surface allows for easy separation of excess reactants through magnetic field application. The solid phase provides a structured platform that maintains assembly flexibility while enabling simple purification by magnetic separation.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The magnetic beads serve as an intermediary solid phase that facilitates both assembly and purification. The beads provide a surface for DNA fragment anchoring while their magnetic properties enable easy separation from excess reactants. This intermediary carrier resolves the contradiction by providing both the flexibility needed for assembly and the ease of separation needed for purification.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Quantity of substance

If high numbers of modules are assembled, then complete TALE arrays can be formed, but plating efficiency decreases

Engineering Contradiction:
Improvemodule numberVSAvoidplating efficiency
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent extracts the verification step from traditional plating procedures by using direct magnetic bead-based detection. Complete TALE arrays are verified through direct analysis of the assembled product on the magnetic bead, eliminating the need for colony formation and plating. This allows assembly of high numbers of modules without the plating efficiency limitations that constrain traditional methods.

Inventive Principle:
Principle #2Taking out (Extraction)

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 enhances the success rate of module recovery, reduces the number of required plasmids, and enables high diversity libraries of TALE DNA binding domains with improved plating efficiency, facilitating automated high-throughput production.

Implementation Method 1

anchoring DNA fragments to facilitate easy removal of excess reactants and enzymes

Methodology Applied
Scientific EffectAdsorption: Adsorption

Data Source

PatentEP2737066B1High throughput method for assembly and cloning polynucleotides comprising highly similar polynucleotidic modules
Publication Date: 2017.11.08 CELLECTIS SA
  • EP2737066B1 patent drawingFigure 1A
  • EP2737066B1 patent drawingFigure 1B
  • EP2737066B1 patent drawingFigure 2A

AI summary

The present invention relates to a method for the assembly and cloning of polynucleotides comprising highly similar polynucleotidic modules, that is highly versatile, does not require intermediate amplification step and can be easily automated for high throughput production of customized polynucleotidic modules.