Self-Regulated Gene Expression via Ribozyme-Aptamer Cassette
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current gene therapy technologies face challenges in regulating transgene expression, leading to unwanted side effects and inefficiencies due to high basal levels of gene expression, dynamic range limitations, and immunologic complications, particularly with existing inducible systems that require multiple components and suffer from variations in expression levels.
Innovation Solution
A self-regulating gene expression system using a dual regulatory cassette with a repressor sequence and ribozyme-aptamer combination, allowing for tight control of transgene expression through inducer molecules, ensuring expression only when needed and minimizing leakiness, suitable for use in viral vectors like adeno-associated virus (AAV).
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If constitutive transgene expression is used, then gene therapy can restore normal physiology, but high basal expression levels cause toxicity and unwanted side effects
Solution Approach 1:
The patent implements dynamic control of transgene expression through inducible regulatory systems that allow the expression level to change from basal to induced states. The regulatory circuitry responds to effector molecules, enabling the system to adapt expression levels to physiological needs rather than maintaining constant high expression that causes toxicity.
Solution Approach 2:
The patent changes the expression parameter from constitutive to inducible by introducing regulatory elements that respond to effector molecules. This allows the transgene expression level to be modulated based on disease state, reducing basal expression to minimize toxicity while enabling high expression when therapeutic benefit is needed.
2Ease of operation
If classical bacterial operon regulatory systems are used, then transgene expression can be induced, but the systems exhibit high basal expression with only modest dynamic range
Solution Approach 1:
The patent combines multiple regulatory elements (promoter, operator sequences, effector molecules) into a composite regulatory system that achieves both low basal expression and high dynamic range. This composite approach integrates the strengths of different regulatory components to overcome the limitations of individual bacterial operon systems.
Solution Approach 2:
The patent designs a universal regulatory system that can control transgene expression with high precision across different contexts. The regulatory circuitry is engineered to provide both tight repression in the basal state and strong induction in the presence of effector molecules, achieving multi-functionality in a single system.
3Reliability
If inducible regulatory systems with multiple components are used, then transgene expression can be regulated, but the systems are too large to fit within single viral vector packaging constraints
Solution Approach 1:
The patent extracts and optimizes the essential regulatory components needed for inducible expression, removing unnecessary elements that increase size. By focusing on the core promoter-operator-effector interaction, the system achieves effective regulation with a minimized genetic circuitry that fits within viral vector packaging constraints.
Solution Approach 2:
The patent segments the regulatory system into compact functional modules that can be efficiently packaged. The regulatory elements are organized into discrete, non-redundant components that maintain functionality while minimizing overall size for viral vector delivery.
4Ease of manufacture
If regulator protein levels are kept constant, then the system is simple to construct, but expression levels vary due to extrinsic variables requiring empirical tuning
Solution Approach 1:
The patent implements feedback mechanisms in the regulatory circuitry that allow the system to sense and respond to environmental conditions. The effector molecules serve as signals that modulate regulator protein activity, creating a feedback loop that adjusts transgene expression levels according to physiological needs without requiring complex constitutive regulation of regulator levels.
Data Source
AI summary
A self-regulating gene expression construct comprises a single promoter in operative association with a repressor sequence (e.g., bacterial repressor lacI or gaiR), operator sequence(s) responsive to the expressed repressor protein, and a transgene. A dual-regulating construct comprises a single promoter controlling expression of a bacterial repressor sequence and a transgene, and which, in the presence of a first inducer molecule, transcribes the transgene and repressor; and a ribozyme in association with an aptamer sequence, the aptamer sequence capable of interacting with a second inducer molecule to terminate mRNA degradation by the ribozyme. Also provided are recombinant vectors or viruses containing the self-regulating or dual self-regulating constructs and cells containing the vectors. Such compositions are useful in methods of treating a diseases using gene therapy.