CLOuD9 Chromatin Looping via dCas9 Fusion
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for studying chromatin architecture are limited by the inability to manipulate chromatin structure without modifying the DNA sequence and the irreversible nature of existing manipulations, which hinders the understanding of chromatin dynamics and its role in gene expression regulation.
Innovation Solution
The development of the CLOuD9 system, which uses CRISPR-dCas9 technology to selectively and reversibly bring chromosomal loci into proximity through a reversible chemical-induced proximity system, allowing for the manipulation of chromatin loops without altering the underlying DNA sequence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If existing chromatin manipulation methods are used, then chromatin structure can be modified, but the DNA sequence must be altered and the manipulation is irreversible
Solution Approach 1:
The patent introduces dCas9 (catalytically inactive Cas9) as an intermediary protein that can be directed to specific chromatin loci via guide RNA without cutting the DNA. By fusing dCas9 with dimerization domains (such as FKBP and FRB), the system enables reversible chromatin looping through chemical induction (e.g., rapamycin treatment), thereby manipulating chromatin structure without altering the underlying DNA sequence.
Solution Approach 2:
The patent utilizes chemical induction to change the dimerization state of fusion proteins in response to external parameters (presence or absence of dimerizing agents like rapamycin). This allows reversible switching between chromatin looped and unlooped states, enabling dynamic manipulation of chromatin architecture without permanent DNA modifications.
2Adaptability or versatility
If existing chromatin manipulation methods are used, then chromatin structure can be modified, but the manipulation is irreversible which hinders understanding of chromatin dynamics
Solution Approach 1:
The patent creates a dynamic system where chromatin loops can be formed and dissolved on demand. The dimerization domains are designed to respond reversibly to chemical inducers, allowing the chromatin architecture to transition between different states. This dynamic control enables researchers to study chromatin dynamics by observing changes in gene expression and chromatin structure in real-time without permanent alterations.
Solution Approach 2:
The system enables periodic manipulation of chromatin structure through repeated cycles of dimerizing agent addition and removal. Each cycle induces chromatin looping followed by dissolution, creating a rhythmic pattern of structural changes that mimics natural chromatin dynamics and allows temporal studies of gene regulation.
3Adaptability or versatility
If dimerization proteins are used to bring chromosomal loci into proximity, then chromatin loops can be formed, but the system complexity increases
Solution Approach 1:
The patent divides the manipulation system into separate functional modules: guide RNA for target recognition, dCas9 for chromatin binding, and dimerization domains for loop formation. Each module performs a specific function and can be independently optimized or modified. This segmentation allows flexible combination of different dCas9 variants from various species with different dimerization systems to achieve desired chromatin looping outcomes.
Solution Approach 2:
The patent employs dCas9 proteins from multiple species (S. pyogenes, S. aureus, N. meningitides, S. thermophiles, T. denticola, S. pasteurianus, N. cinerea, C. lari, P. lavamentivorans, C. diphtheria) that can all perform the same chromatin binding function. This universality allows researchers to select the most appropriate dCas9 variant for their specific application while maintaining compatibility with various guide RNA and dimerization domain combinations.
Data Source
AI summary
Chromatin looping is key to gene regulation, yet no broadly applicable methods to selectively modify chromatin loops have been described. Disclosed herein is an engineered method for chromatin loop reorganization using CRISPR-dCas9 (CLOuD9) to selectively and reversibly establish chromatin loops. Disclosed herein is the power of this technology to selectively modulate gene expression at targeted loci.