Small Guide RNA Hairpin Optimization for CRISPR Specificity
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Solution Overview
Problem
Current CRISPR/Cas systems for genome editing and transcriptional regulation face issues with activity and specificity, often resulting in significant off-target genome editing and varied editing efficiency across different gene targets.
Innovation Solution
A small guide RNA molecule with specific structural features, including a binding region, 5′ and 3′ hairpin regions, and a transcription termination sequence, configured to form a complex with a small guide RNA-mediated nuclease, enhancing stability and activity, and a nuclease-defective Cas9 protein with mutations at specific residues for targeted nucleic acid modification or detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional CRISPR/Cas systems are used for genome editing, then genome editing capability is achieved, but off-target effects increase and editing efficiency varies across different gene targets
Solution Approach 1:
The patent modifies the structural parameters of the guide RNA molecule, specifically optimizing the hairpin region length (at least 31 nucleotides) and composition (fewer than four consecutive uracil nucleotides) to enhance complex stability and nuclease activity, thereby improving both specificity and editing efficiency across different gene targets
Solution Approach 2:
The patent introduces specific local structural features to the guide RNA, including a defined hairpin region with particular nucleotide constraints, to create optimized local interactions that enhance overall system performance and reduce off-target effects while maintaining high editing efficiency
2Stability of the object's composition
If guide RNA structure is optimized for stability, then complex stability increases, but molecular complexity increases
Solution Approach 1:
The guide RNA is segmented into distinct functional regions including a binding region (5-50 nucleotides) and a structured hairpin region (at least 31 nucleotides with specific uracil constraints), allowing each segment to be optimized independently for stability while maintaining overall system manageability
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 optimized CRISPR system achieves improved specificity and efficiency in nucleic acid modification and detection, reducing off-target effects and enhancing labeling efficiency of genomic elements in living cells.
Implementation Method 1
a small guide RNA molecule comprising from 5′ to 3′: a binding region, comprising between about 5 and about 50 nucleotides; a 5′ hairpin region
Implementation Method 2
a 5′ hairpin region, comprising: fewer than four consecutive uracil nucleotides; or a length of at least 31 nucleotides; and a 3′ hairpin region
Implementation Method 3
Binding of the CRISPR:Cas complex to the target sequence results in double stranded cleavage of the target sequence
Implementation Method 4
a CRISPR:Cas complex that contains the Cas nuclease and a guide RNA derived from the CRISPR sequences that provides target sequence specificity through a single stranded binding region
Data Source
AI summary
Methods, compositions, and kits are provided herein for CRISPER/Cas-mediated nucleic acid detection or modification.