Fluorescence Cleavage Substrates for High-Throughput Cas9 Screening
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Solution Overview
Problem
Current methods lack high-throughput assays for characterizing Cas protein activity and understanding interactions with compounds that impact its efficacy, necessitating the development of synthetic substrates and assay methods for biochemical studies.
Innovation Solution
Design and use of cleavage substrates with fluorophore and quencher labels that emit a detectable signal upon cleavage by Cas proteins, allowing for quantitative monitoring of nuclease activity through fluorescence spectroscopy in a high-throughput microplate format, including specific nucleic acid sequences and structures to interact with Cas proteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional nuclease activity detection methods are used, then the assay can detect Cas protein activity, but the throughput is low and cannot support high-throughput screening of compounds
Solution Approach 1:
The patent replaces traditional mechanical or manual nuclease activity detection methods with a fluorescence-based optical detection system. The cleavage substrate incorporates fluorophore and quencher labels that generate a fluorescent signal upon Cas protein-mediated cleavage, enabling automated, high-throughput reading in microplate formats without complex manual intervention
Solution Approach 2:
The patent changes the detection parameter from traditional methods (such as gel electrophoresis or radiolabeling) to fluorescence intensity measurement. By using fluorophore-quencher pairs that generate measurable fluorescent signals upon cleavage, the assay parameters are optimized for high-throughput screening while maintaining simplicity in execution
2Measurement precision
If cleavage substrates with fluorophore and quencher labels are used, then quantitative monitoring of nuclease activity is enabled, but the substrate design and synthesis becomes more complex
Solution Approach 1:
The patent introduces fluorophore and quencher labels as intermediary molecules attached to the cleavage substrate. These labels serve as mediators that translate the biochemical cleavage event into a quantifiable fluorescent signal, enabling precise measurement of nuclease activity without requiring complex detection instrumentation
Solution Approach 2:
The cleavage substrate is designed as a composite structure incorporating nucleic acid sequences, fluorophore labels, and quencher labels in a single integrated molecule. This composite design allows the substrate to simultaneously perform target recognition, signal generation, and quantification functions, improving measurement precision while the modular nature facilitates standardized synthesis
3Productivity
If high-throughput microplate format is used for assay, then compound screening efficiency is improved, but the assay setup and data analysis becomes more complex
Solution Approach 1:
The fluorescence-based cleavage assay is designed to be universally applicable across multiple compounds and Cas protein variants using the same basic protocol. The standardized substrate design and detection method allow the same assay setup to screen numerous compounds in parallel without requiring separate optimization for each, thereby improving screening efficiency while maintaining procedural simplicity
Solution Approach 2:
The patent employs identical cleavage substrate designs and assay protocols replicated across multiple microplate wells to screen numerous compounds simultaneously. This copying approach allows high-throughput screening by performing parallel measurements with minimal variation in setup procedures, improving efficiency while the standardized replication reduces overall complexity through consistency
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
Enables quantitative monitoring of Cas9 cleavage activity and testing of compounds for inhibition or activation, providing insights into Cas protein interactions and efficacy in biochemical studies.
Implementation Method 1
The fluorophore and the quencher form a Forster resonance energy transfer (FRET) pair, in which the two labels are in close proximity within the duplex, such that fluorescence emission is quenched
Implementation Method 2
Upon cleavage of the duplex substrate, the distance between the two labels is increased, thereby allowing for a quantitative increase in fluorescence signal based on extent of nuclease activity
Data Source
AI summary
The present invention relates, in part, to methods for detecting nuclease activity, such as the activity of Cas nucleases. Also described herein are compositions for conducting assays, as well as methods for conducting assays in the presence of test compounds.