CaRROT Optogenetic System for Precise Gene Expression Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for modulating gene expression, such as those using catalytically inactive CRISPR/Cas9 (dCas9), lack temporal control and suffer from off-target effects and lack strict reversibility, making them inefficient for precise gene regulation.
Innovation Solution
A calcium-responsive transcriptional reprogramming device (CaRROT) is developed, combining a photoswitchable calcium actuator with dCas9, allowing for light- or chemically inducible control of gene expression by fusing an engineered Ca2+-responsive NFAT fragment with dCas9 and transcriptional coactivators, enabling precise spatiotemporal control of gene expression.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dCas9 is used for gene expression modulation, then gene transcription can be reprogrammed at targeted loci, but temporal control is lost leading to off-target effects and lack of reversibility
Solution Approach 1:
The system is divided into two separate components: a dCas9 fusion protein that remains cytoplasmic and an optogenetic module (LOV2-NLS) that controls nuclear translocation. This segmentation allows the dCas9 to be stored in an inactive state in the cytoplasm and only enter the nucleus when light is applied, providing temporal control and reducing off-target effects while maintaining the gene editing function
Solution Approach 2:
The dCas9 fusion protein is pre-prepared with the optogenetic control module attached, but kept in the cytoplasm in an inactive state before light stimulation. This preliminary positioning allows for rapid activation upon light exposure without requiring de novo synthesis or complex assembly steps, enabling quick temporal control while simplifying the overall system design
2Productivity
If continuous gene expression modulation is applied, then gene transcription is activated, but off-target effects increase and reversibility is lost
Solution Approach 1:
The system uses light stimulation to periodically activate dCas9 nuclear translocation only when needed. By applying light in specific time windows, the system achieves precise temporal control over gene expression activation, ensuring that dCas9 enters the nucleus only during intended treatment periods and returns to the cytoplasm otherwise, thereby minimizing off-target effects while maintaining productive gene modulation when required
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 CaRROT system achieves high precision in modulating gene expression with reduced off-target effects and strict reversibility, allowing for controlled activation or repression of genes in mammalian cells using light or chemical inducers.
Implementation Method 1
the NIR-stimulable optogenetic platform photoactivates ORAI calcium channels to thereby induce Ca2+ influx
Implementation Method 2
the transcription reprogramming component translocates from cytosol to the nucleus upon at least one of photoactivation and chemical activation
Data Source
AI summary
In an embodiment, a device for modulating intracellular gene expression, the device having a calcium actuator component and a transcription reprogramming component. In another embodiment, a method for modulating intracellular gene expression, where the method includes inducing a system having a calcium actuator component and a transcription reprogramming component with at least one of light and a chemical, causing an increase in Ca2+, and translocating the transcription reprogramming component from cytosol to the nucleus. In a further embodiment, a method for modulating gene intracellular expression, where the method includes inducing a system having an NIR-stimulable optogenetic platform with at least one of light and a chemical, where the NIR-stimulable optogenetic platform facilitates Ca2+ release and the NIR-stimulable optogenetic platform is LOV2-SOAR, causing an increase in Ca2+, and translocating a calcium-responsive dCas9 fusion construct from cytosol to the nucleus, where the calcium-responsive dCas9 fusion construct is NFAT1-460-dCas9-VP64.