Engineered SaCas9 Enzymes and Guide RNAs for Precise Genome Editing
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Solution Overview
Problem
Current genome editing technologies, such as CRISPR-Cas systems, face challenges in achieving precise and efficient targeting of specific DNA sequences in eukaryotic genomes, with limitations in scalability, ease of use, and specificity, particularly for multiple targeting applications.
Innovation Solution
The development of engineered CRISPR-Cas systems, including optimized Staphylococcus aureus Cas9 (SaCas9) enzymes and guide RNAs, which allow for enhanced specificity and efficiency by modifying the enzyme and RNA architectures to improve binding properties and cleavage activities, reducing off-target effects and increasing targeting precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If CRISPR-Cas systems are used for genome editing, then targeting capability is improved, but off-target effects increase
Solution Approach 1:
The patent applies local quality by engineering specific modifications at particular locations within the Cas9 enzyme structure and guide RNA architecture. These localized modifications enhance binding specificity at the target site while maintaining overall system function, thereby improving targeting precision without proportionally increasing off-target effects throughout the entire genome.
Solution Approach 2:
The patent employs parameter changes by systematically varying key parameters such as guide RNA sequence composition, Cas9 enzyme amino acid residues, and binding affinity thresholds. By optimizing these parameters, the system achieves higher discrimination between on-target and off-target sequences, resolving the contradiction between targeting capability and off-target effects.
2Adaptability or versatility
If CRISPR-Cas systems are engineered for multiple targeting, then versatility is improved, but system complexity increases
Solution Approach 1:
The patent implements universality by designing a standardized CRISPR-Cas platform that can target multiple genomic locations through interchangeable guide RNA molecules. The engineered Cas9 enzyme maintains a consistent interface that accommodates various guide sequences, enabling multiple targeting applications without requiring separate complex systems for each target, thus improving versatility while controlling complexity.
Solution Approach 2:
The patent applies segmentation by separating the targeting function into modular components: a stable engineered Cas9 enzyme core and interchangeable guide RNA segments. This modular architecture allows independent optimization of each component and enables combinatorial targeting strategies without proportionally increasing overall system complexity, as each new target requires only a new guide segment rather than a completely new system.
3Manufacturing precision
If guide RNA architecture is modified to improve specificity, then binding precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent uses parameter changes by systematically optimizing guide RNA structural parameters such as stem-loop configuration, seed sequence composition, and overall length. These parameter optimizations improve binding precision while maintaining compatibility with standard RNA synthesis methodologies, balancing manufacturing ease with functional precision through rational design rather than requiring complex synthetic procedures.
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
The engineered CRISPR-Cas systems demonstrate improved targeting efficiency and specificity, enabling more precise genome editing with reduced off-target binding, thus simplifying the methodology for cataloging genetic factors associated with biological functions and diseases.
Implementation Method 1
a guide sequence capable of hybridizing to a target sequence in a genomic locus of interest
Implementation Method 2
the CRISPR enzyme is capable of effecting the manipulation of a target nucleic acid within the cell
Data Source
AI summary
The invention provides for systems, methods, and compositions for altering expression of target gene sequences and related gene products. Provided are structural information on the Cas protein of the CRISPR-Cas system, use of this information in generating modified components of the CRISPR complex, vectors and vector systems which encode one or more components or modified components of a CRISPR complex, as well as methods for the design and use of such vectors and components. Also provided are methods of directing CRISPR complex formation in eukaryotic cells and methods for utilizing the CRISPR-Cas system. In particular the present invention comprehends optimized functional CRISPR-Cas enzyme systems. In particular the present invention comprehends engineered new guide architectures and enzymes to be used in optimized Staphylococcus aureus CRISPR-Cas enzyme systems.