Helper Plasmid Architecture for Higher Recombinant AAV Yield
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Solution Overview
Problem
The limited capacity of large-scale production of adeno-associated virus (AAV) restricts the clinical applications of gene therapy, necessitating an increase in AAV yield to reduce production costs.
Innovation Solution
A helper plasmid containing a coding sequence of AAV Rep and Cap proteins, combined with a DA′ or AD′ sequence and a P5 promoter, is used to enhance AAV production in host cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a traditional three-plasmid transfection method is used for AAV production, then the production process is simple and rapid, but the AAV yield is limited
Solution Approach 1:
The plasmid is segmented into functional modules: Rep/Cap coding regions, ITR sequences positioned at specific locations, and promoter elements. This modular segmentation allows optimization of each component's function while maintaining overall plasmid manageability and improving AAV yield through enhanced replication and packaging efficiency
Solution Approach 2:
The patent introduces a novel plasmid architecture dimension by positioning ITR sequences in non-traditional locations (including within coding regions and at multiple positions), transforming the conventional linear plasmid structure into a multi-dimensional functional arrangement that enhances viral production without proportionally increasing operational complexity
2Productivity
If ITR sequences are included in the plasmid to enable AAV replication and packaging, then viral production is enabled, but transcriptional activity is very low compared to traditional promoters
Solution Approach 1:
The patent merges the promoter function with ITR sequences by combining transcriptional activation capabilities with replication/packaging signals in integrated genetic elements. This merging allows the ITR-containing regions to simultaneously provide both structural functions for viral assembly and transcriptional drive, overcoming the low transcriptional activity limitation while maintaining AAV production capacity
Solution Approach 2:
The plasmid design uses composite genetic elements that combine ITR sequences with enhanced promoter activities and coding regions. These composite structures integrate multiple functional properties (replication signals, packaging signals, transcriptional activation) into unified genetic constructs that achieve high AAV production with improved transcriptional efficiency
Data Source
AI summary
The present application provides a helper plasmid for preparing a recombinant adeno-associated virus (rAAV), including: 1) a coding sequence of an AAV Rep protein and a coding sequence of an AAV Cap protein; 2) at least one promoter sequence; and 3) at least one DA′sequence or AD′ sequence, wherein the AD′ sequence is a reverse complementary sequence of the DA′ sequence. The present application also provides a method for increasing a production capacity of a rAAV using the helper plasmid. With an AD′ sequence or a DA′ sequence, the helper plasmid provided in the present application can significantly increase an AAV yield of a cell.