AAV Vector Stuffer Sequence Packaging Efficiency

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Solution Overview

Problem

Current AAV vectors face challenges in packaging efficiency due to the need for full-length genome size and the inclusion of enhancers, promoters, splicing regulators, noncoding RNAs, or antisense sequences, which can lead to heterogeneous virions and reduced packaging efficacy.

Innovation Solution

A nucleic acid stuffer sequence of 3300-4200 nucleotides in length, with at least 90% identity to specific sequences, is used to create an AAV vector that is devoid of enhancers, promoters, splicing regulators, noncoding RNAs, or antisense sequences, ensuring optimal packaging and expression cassette functionality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If traditional AAV vectors include enhancers, promoters, splicing regulators, noncoding RNAs, or antisense sequences to maintain full-length genome size, then the genome completeness is improved, but the packaging efficiency deteriorates and heterogeneous virions are produced

Engineering Contradiction:
Improvegenome completenessVSAvoidpackaging efficiency
Core Design Contradiction:
Stability of the object's compositionVSProductivity

Solution Approach 1:

The invention extracts and removes all functional genetic elements (enhancers, promoters, splicing regulators, noncoding RNAs, antisense sequences) from the AAV vector genome, retaining only the essential ITRs and expression cassette. This extraction eliminates the sources of transcriptional and post-transcriptional regulation that cause heterogeneous virion production, thereby improving packaging efficiency while maintaining genome stability through the retained essential elements.

Inventive Principle:
Principle #2Taking out (Extraction)

2Productivity

If AAV vectors are designed with simplified genomes lacking functional elements, then packaging efficiency is improved, but the genome size may deviate from wild-type and affect capsid packaging

Engineering Contradiction:
Improvepackaging efficiencyVSAvoidgenome size consistency
Core Design Contradiction:
ProductivityVSStability of the object's composition

Solution Approach 1:

The invention changes the genome size parameter to precisely 3.7-4.2 kb by removing all non-essential elements while retaining the ITRs and expression cassette. This parameter optimization ensures the genome falls within the optimal packaging range for AAV capsids, achieving both high packaging efficiency and consistent genome size that mimics wild-type AAV characteristics.

Inventive Principle:
Principle #35Parameter changes

3Adaptability or versatility

If AAV vectors contain multiple regulatory elements for gene expression control, then expression flexibility is improved, but virion heterogeneity increases and packaging becomes less efficient

Engineering Contradiction:
Improveexpression control flexibilityVSAvoidvirion homogeneity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention extracts all regulatory elements responsible for transcriptional and post-transcriptional control (enhancers, promoters, splicing regulators, noncoding RNAs) from the vector genome. This removal eliminates the mechanisms that generate virion heterogeneity, resulting in highly homogeneous virus particles with consistent packaging efficiency, while the essential expression cassette remains functional for gene delivery.

Inventive Principle:
Principle #2Taking out (Extraction)

Data Source

PatentEP2870237B1Modified adeno-associated virus vector compositions
Publication Date: 2018.09.26 THE UNIVERSITY OF IOWA RESEARCH
  • EP2870237B1 patent drawingFigure 1
  • EP2870237B1 patent drawingFigure 2
  • EP2870237B1 patent drawingFigure 2

AI summary

An adeno-associated virus filler component comprising a nucleic acid of between 3300 and 4200 nucleotides in length is disclosed.