Nuclease-Directed Integration for Eukaryotic Binder Libraries
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Solution Overview
Problem
Current methods for creating libraries of binders in eukaryotic cells face challenges such as random integration of DNA, low transformation efficiencies, and difficulty in achieving large library sizes, which limits the ability to screen for binders with desired properties.
Innovation Solution
The use of nuclease-directed integration, where site-specific nucleases target specific loci in the eukaryotic genome for precise integration of binder genes, enhancing site-specific integration through endogenous cellular repair mechanisms, allowing for the creation of large populations of cells expressing different binders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If random integration of donor DNA into eukaryotic cells is used, then transformation can occur, but integration precision is poor and library quality is reduced
Solution Approach 1:
The patent introduces site-specific nucleases (such as ZFNs, TALENs, or CRISPR-Cas9 systems) as intermediary tools that mediate the integration process. These nucleases recognize specific DNA sequences and create controlled double-strand breaks at predetermined locations, enabling precise integration of donor DNA. The homology arms on the donor DNA molecule act as intermediaries that guide the integration to the correct location through homologous recombination, resolving the contradiction between precision and ease of manufacture.
Solution Approach 2:
The patent employs preliminary action by first designing and introducing site-specific nucleases into the eukaryotic cells before introducing the donor DNA. The nucleases pre-establish the integration site by creating double-strand breaks at specific genomic locations. Additionally, the donor DNA is designed with homology arms that match the sequences flanking the nuclease cut sites, preparing the DNA for precise integration. This preliminary preparation enables high-precision integration while maintaining ease of the overall process.
2Productivity
If traditional transfection methods are used, then donor DNA can be introduced, but transformation efficiency is low and library size is limited
Solution Approach 1:
The patent uses site-specific nucleases as intermediaries to dramatically enhance transformation efficiency. By creating specific double-strand breaks at predetermined genomic locations, the nucleases activate the cell's endogenous DNA repair mechanisms (homologous recombination or non-homologous end joining), which efficiently incorporate the donor DNA. This intermediary approach increases transformation efficiency from typically less than 1% with traditional methods to over 50% in many cases, enabling the creation of large-scale libraries with thousands to millions of independent clones.
Solution Approach 2:
The patent leverages the cell's own endogenous DNA repair mechanisms (homologous recombination and non-homologous end joining) to perform the integration service. By introducing site-specific nucleases that create controlled double-strand breaks, the system activates these self-service repair pathways, which automatically incorporate the donor DNA with homology arms at the correct locations. This self-service approach eliminates the need for complex external manipulation and significantly improves transformation efficiency and library size.
3Adaptability or versatility
If multiple donor DNA molecules are introduced per cell, then diversity is increased, but integration control is lost and uniformity decreases
Solution Approach 1:
The patent applies local quality by creating multiple independent integration sites throughout the genome, each targeted by specific site-specific nucleases. Each site has unique characteristics (different genomic contexts, different nuclease specificities), allowing controlled introduction of multiple donor DNA molecules. The homology arms on each donor DNA molecule are designed to match specific local sequences at these distributed sites, enabling diverse integration locations while maintaining uniform integration mechanics at each site. This approach preserves both library diversity and integration uniformity.
Solution Approach 2:
The patent segments the integration process by dividing the genome into multiple discrete target locations, each recognized by specific site-specific nucleases. Rather than attempting simultaneous control of multiple integrations at a single site, the system segments the task into independent integration events at different genomic locations. Each segment (integration site) can independently accept donor DNA molecules, and the segmentation allows for controlled diversity while maintaining uniformity within each segment. This segmentation strategy enables the creation of large, diverse libraries with consistent integration characteristics.
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 enables the construction of high-quality libraries with uniform transcription levels and high efficiency, facilitating the identification of binders with specific properties by ensuring accurate and controlled integration of binder genes, thereby overcoming previous limitations in library size and random integration.
Implementation Method 1
providing a site-specific nuclease within the cells, wherein the nuclease cleaves cellular DNA to create an integration site
Implementation Method 2
integration occurring through DNA repair mechanisms endogenous to the cells
Data Source
AI summary
The invention relates to methods of producing eukaryotic cell libraries encoding a repertoire of binding molecules (“binders”), wherein the methods use a site-specific nuclease for targeted cleavage of cellular DNA to enhance site-specific integration of binder genes through endogenous cellular repair mechanisms. Populations of eukaryotic cells are produced in which a repertoire of genes encoding binders are integrated into a desired locus in cellular DNA (e.g., a genomic locus) allowing expression of the encoded binding molecule, thereby creating a population of cells expressing different binders.