DNA-Barcoded Nucleosome Spike-Ins for Tethered Enzyme Assays
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current chromatin mapping and accessibility assays lack reliable spike-in controls for normalizing samples, monitoring antibody performance, and addressing technical variability, particularly in assays using tethered enzymes like CUT&RUN or CUT&Tag, due to the incompatibility of existing DNA-barcoded nucleosomes with linker DNA and enzyme targeting.
Innovation Solution
Engineered DNA-barcoded recombinant nucleosomes with modified nucleosome positioning sequences containing linker DNA and nuclease or transposase recognition sites, enabling targeting by enzymes used in chromatin accessibility assays, and optionally including a binding moiety for immobilization, serving as spike-in controls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing DNA-barcoded nucleosomes are used as spike-in controls, then sample normalization and antibody performance monitoring are enabled, but they are incompatible with tethered enzyme assays (CUT&RUN/CUT&Tag) due to lack of linker DNA and enzyme targeting sites
Solution Approach 1:
The nucleosome construct is divided into functional segments: a core nucleosome positioning sequence (147 bp), optional linker DNA regions, enzyme recognition sequences, and DNA barcode regions. This segmentation allows each component to fulfill its specific function while maintaining overall compatibility with tethered enzyme assays.
Solution Approach 2:
Linker DNA sequences serve as intermediaries between the core nucleosome structure and the tethered enzymes. These linker regions provide the necessary physical connection and spatial arrangement for enzymes like Tn5 or MNase to access and process the nucleosome, enabling assay compatibility without compromising spike-in control functionality.
2Adaptability or versatility
If DNA-barcoded nucleosomes include linker DNA and enzyme recognition sites for CUT&RUN/CUT&Tag compatibility, then assay versatility is improved, but the complexity of nucleosome construction and validation increases
Solution Approach 1:
The engineered nucleosome constructs are designed to serve multiple functions: they act as spike-in controls for normalization, provide binding targets for tethered enzymes (Tn5, MNase), contain DNA barcodes for identification and quantification, and maintain proper nucleosome structure. This multi-functionality reduces the need for separate control elements for each assay type.
Solution Approach 2:
The nucleosome constructs utilize variations in DNA sequence parameters (linker length, composition, and position) and histone modification parameters to optimize enzyme accessibility and binding while maintaining nucleosome stability. These parameter adjustments enable compatibility across different assay conditions without fundamentally redesigning the nucleosome core.
3Adaptability or versatility
If nucleosome spike-in controls are engineered with modified positioning sequences and additional functional elements, then enzyme targeting capability is improved, but manufacturing precision requirements increase
Solution Approach 1:
The nucleosome positioning sequences and linker regions are pre-designed and pre-assembled with precise spacing and orientation before enzyme binding occurs. This preliminary structuring ensures that when tethered enzymes are introduced, they encounter optimally positioned recognition sites, reducing variability in enzyme-nucleosome interactions and simplifying manufacturing tolerances.
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
Provides reliable normalization, monitoring of antibody performance, and technical variability assessment in chromatin mapping and accessibility assays, including bulk, single-cell, and cell-free analyses, enhancing data accuracy and reliability.
Implementation Method 1
containing linker DNA and nuclease or transposase recognition sites, enabling targeting by enzymes used in chromatin accessibility assays
Data Source
AI summary
The present invention relates to DNA-barcoded recombinant nucleosomes and polynucleosomes that have been engineered for use as spike-in controls for chromatin accessibility assays, chromatin mapping assays, e.g., using tethered enzymes, as well as other chromatin assays. The invention further relates to methods of using the engineered DNA-barcoded recombinant nucleosomes in chromatin accessibility assays, chromatin mapping assays, as well as other chromatin assays.