BRET Biosensor for CRISPR-Cas Specificity Assessment
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Solution Overview
Problem
Current methods for analyzing DNA double-strand breaks induced by CRISPR-Cas systems are not sensitive enough and are not suitable for high-throughput applications, leading to inefficiencies in assessing off-target mutations and specificity, which is crucial for reliable genome editing.
Innovation Solution
A biosensor system utilizing bioluminescence resonance energy transfer (BRET) technology to measure the restriction efficiency of endonucleases by encoding a DNA target sequence in a vector with Luciferase 8 and GFP2, allowing for the quantification of DNA double-strand breaks and insertions or deletions, thereby assessing the specificity of CRISPR-Cas systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional reporter systems (e.g., Traffic Light Reporter, surveyor nuclease assay) are used to detect DNA double-strand breaks, then qualitative assessment of DSB events is possible, but the methods are not sensitive enough, time-consuming, and not suitable for high-throughput applications
Solution Approach 1:
The patent replaces traditional mechanical/chemical detection methods (PCR amplification, gel electrophoresis, enzymatic assays) with a bioluminescent optical detection system. The BRET-based biosensor converts DSB events into light signals that can be quantified by luminometry, eliminating the need for time-consuming PCR and electrophoresis steps while dramatically increasing sensitivity and throughput capability.
Solution Approach 2:
The patent changes the detection parameter from qualitative/semi-quantitative methods to a quantitative bioluminescent signal. By measuring light intensity (luminosity) directly proportional to the number of DSB events, the system achieves both high sensitivity and the ability to process multiple samples in parallel, enabling high-throughput application.
2Measurement precision
If PCR amplification is used in surveyor nuclease assay to detect mutations, then mutation detection is possible, but PCR artifacts increase background noise and the method becomes elaborate and expensive
Solution Approach 1:
The patent extracts the detection function from the complex PCR-amplification-enzyme-treatment-electrophoresis workflow and isolates it into a single biosensor molecule that directly reports DSB events through bioluminescence. This eliminates the need for PCR amplification entirely, removing the source of artifacts and simplifying the methodology.
Solution Approach 2:
The patent introduces a bioluminescent reporter system as an intermediary that directly translates DSB events into measurable light signals. This intermediary bypasses the need for PCR amplification and enzymatic processing, providing a direct readout that is both simpler and more reliable than traditional methods.
3Manufacturing precision
If CRISPR-Cas systems are used for genome editing, then precise DNA modification is achieved, but off-target mutations occur that reduce reliability
Solution Approach 1:
The patent implements a feedback mechanism where the bioluminescent biosensor provides real-time quantitative data on both on-target and off-target DSB events. This feedback allows researchers to optimize gRNA design, Cas9 variants, and experimental conditions to maximize specificity and minimize off-target effects, thereby improving overall reliability.
Solution Approach 2:
The patent enables preliminary assessment of CRISPR-Cas system specificity before actual genome editing experiments. By using the BRET biosensor to screen and validate gRNA candidates in advance, researchers can identify and eliminate sequences prone to off-target effects, ensuring higher reliability in subsequent editing applications.
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 BRET ratio effectively correlates with the restriction efficiency of CRISPR-Cas systems, enabling the direct measurement of DNA double-strand breaks and associated insertions or deletions, thus improving the assessment of CRISPR-Cas specificity and suitability for high-throughput applications.
Implementation Method 1
wherein the BRET (bioluminescence resonance energy transfer) technology is involved as readout
Implementation Method 2
bioluminescence resonance energy transfer ratio (BRET)
Data Source
Figure 1
Figure 2A~2B
AI summary
The invention describes a new method involving bioluminescence resonance energy transfer ratio for determination of restriction efficiency of endonucleases or endonuclease systems comprising a guide-RNA that are used for induction of double-strand breaks at a DNA target sequence of interest for genome editing approaches. The method is suitable for high throughput analyses of potential DNA target sites in combination with different endonuclease-guide-RNA complexes.