Multiplex shRNA Vector Layout to Limit Recombination and Off-Target Effects
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Solution Overview
Problem
Current vector technologies for delivering multiplexed shRNAs face challenges such as vector recombination, reduced shRNA functionality, complexity in cloning, RNAi processing saturation, cytotoxicity, and undesirable off-target effects, limiting effective simultaneous delivery of multiple shRNAs.
Innovation Solution
Development of polynucleotides and vectors that include a multiplexed microRNA-based shRNA encoding region with specific scaffold and linker sequences, allowing for efficient expression of multiple shRNAs, minimizing recombination and off-target effects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate vectors are used for each shRNA, then shRNA functionality is maintained, but delivery complexity and difficulty increase
Solution Approach 1:
The patent combines multiple shRNA expression cassettes into a single vector system, allowing simultaneous delivery of multiple shRNAs through one vector rather than requiring separate vectors for each shRNA, thereby reducing delivery complexity while maintaining functionality
Solution Approach 2:
The vector is designed with universal features that enable it to express multiple different shRNAs through interchangeable expression cassettes, making the same vector capable of delivering various combinations of shRNAs for different gene targets
2Device complexity
If multiple shRNAs are delivered in a single vector, then delivery complexity is reduced, but vector recombination and loss of shRNA expression occur
Solution Approach 1:
The vector is divided into modular expression cassettes, each containing an shRNA expression unit separated by insulator sequences. This segmentation prevents recombination between adjacent shRNA elements while allowing each cassette to function independently, thereby maintaining expression stability
Solution Approach 2:
Insulator sequences are introduced as intermediary elements between adjacent shRNA expression cassettes. These insulators act as protective barriers that prevent recombination events and maintain the stability of shRNA expression across multiple generations
3Productivity
If multiple shRNAs are expressed in a multiplex cassette, then delivery efficiency is improved, but shRNA functionality is reduced by positional effects
Solution Approach 1:
Each shRNA expression cassette is designed with local optimization features, including specific promoter elements and insulator sequences positioned at strategic locations. This ensures that each shRNA maintains its functionality regardless of its position within the multiplex cassette, eliminating positional effects
4Adaptability or versatility
If complex multiplex systems are developed, then multiple shRNA delivery capability is achieved, but cloning complexity increases
Solution Approach 1:
The system uses standardized, modular expression cassettes that can be independently cloned and then assembled into the final multiplex vector. This segmentation simplifies the cloning process by allowing researchers to work with smaller, manageable units rather than attempting to construct entire multiplex systems in a single cloning step
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 solution enables effective and efficient silencing of multiple gene targets with reduced off-target effects, enhancing the functionality and safety of shRNA delivery systems.
Implementation Method 1
shRNAs are single stranded molecules that contain a sense region and an antisense region that is capable of hybridizing with the sense region. shRNAs are capable of forming a stem and loop structure in which the sense region and the antisense region form part or all of the stem.
Implementation Method 2
siRNAs can cause cleavage of a target molecule, such as mRNA. Similar to miRNAs, in order to recognize a target molecule, siRNAs rely on the complementarity of bases.
Data Source
AI summary
New polynucleotides and new expression vectors for multiplexed microRNA-based shRNAs are provided. The shRNAs generated from these polynucleotides and vectors can knock down the expression of multiple genes with minimum undesirable levels of off-target effects.