Synthetic AAV ITRs for Enhanced Packaging Capacity
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Solution Overview
Problem
Current methods for synthesizing functional mutant inverted terminal repeats (ITRs) of adeno-associated virus (AAV) are limited, with most reports using natural ITR sequences from AAV serotype 2, and there is a need for alternatives that can enhance transduction efficiency, cellular response manipulation, and packaging capacity.
Innovation Solution
Development of synthetic AAV ITRs comprising an AAV rep binding element, terminal resolution sequence, and RBE' element, without any other AAV ITR sequences, which can be designed to alter transcription factor binding sites, CpG motifs, and other sequences to modify cellular responses and transduction characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If natural AAV ITR sequences are used, then basic viral functions are maintained, but packaging capacity is limited and transduction efficiency cannot be optimized
Solution Approach 1:
The patent divides the ITR sequence into three functional modules: rep binding element (RBE), terminal resolution sequence (TRS), and RBE' element. This segmentation allows independent optimization of each module for packaging capacity while maintaining essential viral functions, resolving the contradiction between increased packaging capacity and sequence design complexity.
Solution Approach 2:
The patent employs synthetic ITR sequences with modified nucleotide compositions and altered binding affinities compared to natural ITRs. By changing parameters such as GC content, sequence length, and binding site affinity, the patent achieves enhanced packaging capacity and transduction efficiency while using standardized modular components to manage design complexity.
2Adaptability or versatility
If natural AAV ITR sequences are used, then viral replication functions are preserved, but cellular response manipulation is limited
Solution Approach 1:
The patent applies local quality changes by specifically modifying certain regions of the ITR sequence (such as transcription factor binding sites and CpG motifs) while preserving other critical regions. This allows tailored manipulation of cellular responses in specific locations without compromising overall viral replication functions, achieving both adaptability and reliability.
Solution Approach 2:
The patent introduces synthetic ITR sequences as intermediaries between natural viral sequences and host cellular machinery. These synthetic sequences mediate controlled interactions with cellular transcription factors and immune recognition systems, enabling versatile cellular response manipulation while maintaining reliable viral replication through preserved core functional elements.
3Productivity
If natural AAV ITR sequences are used, then vector production is straightforward, but transduction efficiency cannot be enhanced
Solution Approach 1:
The patent creates synthetic copies of the essential ITR functional elements (RBE, TRS, RBE') with optimized sequences. These copied and refined modules can be assembled using standard molecular biology techniques, making manufacturing straightforward while achieving enhanced transduction efficiency through optimized sequence designs derived from natural ITRs.
4Adaptability or versatility
If natural AAV ITR sequences are used, then basic genome persistence is achieved, but DNA damage response and apoptosis cannot be controlled
Solution Approach 1:
The patent modifies specific parameters of the ITR sequence, particularly CpG motif composition and transcription factor binding site architecture, to control DNA damage responses and apoptosis. By systematically adjusting these nucleotide-level parameters in the synthetic ITR design, the patent achieves controlled cellular responses without requiring complex multi-component systems.
Data Source
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AI summary
This invention relates to synthetic adeno-associated virus (AAV) inverted terminal repeats (ITRs) that exhibit altered activities compared to a naturally occurring AAV ITR and methods of using the same for delivery of nucleic acids to a cell or a subject. The synthetic ITRs provide a larger packaging capacity and the ability to manipulate activities such as transduction efficiency, cellular response to transduction, and transcription.