Nucleic Acid Concatemers for Controlled Multi-Protein Co-Expression
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Solution Overview
Problem
Existing methods for producing recombinant products with multiple components face challenges in achieving controlled ratiometric co-expression, particularly with plasmid constructs, which result in widely varying protein ratios and complicate purification due to bacterial contamination and sequence-based competition for host factors.
Innovation Solution
The use of nucleic acid concatemers, generated through strand-displacement amplification like rolling circle amplification, allows for the formulation of mixtures with predefined ratios to co-express multiple expression products, overcoming size-related transfection inefficiencies and eliminating bacterial contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple plasmid constructs are used for co-expression, then multiple proteins can be produced, but the protein expression ratios vary widely and purification is complicated by bacterial contamination
Solution Approach 1:
The patent divides the multi-component expression system into separate concatemer molecules, where each concatemer contains one or more open reading frames (ORFs) flanked by ITRs. This segmentation allows each concatemer to be independently quantified and mixed at precise molar ratios, enabling controlled co-expression of multiple proteins while avoiding the contamination and ratio control issues of plasmid-based systems
Solution Approach 2:
The patent uses rolling circle amplification to generate multiple copies of each concatemer sequence, creating a pool of identical concatemer molecules that can be precisely quantified and mixed. This copying process ensures that each concatemer in the mixture is a faithful replicate, enabling accurate ratiometric control of protein expression without the variability inherent in plasmid transfection
2Ease of manufacture
If plasmid constructs are used, then bacterial production and maintenance is enabled, but post-production purification becomes difficult due to bacterial chromosomal DNA contamination
Solution Approach 1:
The patent extracts the essential functional elements (ORFs and ITRs) from the bacterial plasmid context and assembles them into synthetic concatemer sequences that do not require bacterial maintenance. This extraction eliminates the need for bacterial chromosomal DNA sequences, allowing straightforward purification of the expression templates without contamination from bacterial genomic DNA
Solution Approach 2:
Instead of using bacterial plasmids that require bacterial hosts for maintenance and purification, the patent inverts the approach by using synthetic DNA sequences that can be produced in vitro through rolling circle amplification. This inversion eliminates the bacterial production step entirely, simplifying purification and avoiding contamination issues
3Adaptability or versatility
If separate plasmids are transfected into cells, then multiple proteins can be expressed, but transfection efficiency and ratio control are reduced due to sequence-based competition for host factors
Solution Approach 1:
The patent changes the fundamental parameter of the expression template from plasmid DNA to linear concatemer DNA with ITRs. This parameter change eliminates the sequence-based competition for host factors that plasmids experience, as the concatemers are processed differently by the cellular machinery (through AAV replication and transcription pathways), thereby improving transfection efficiency and enabling better ratio control
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
This approach enables robust, high-efficiency co-expression of recombinant products with predictable ratios and simplified purification, suitable for cGMP manufacturing, and reduces labor and costs compared to traditional plasmid-based methods.
Implementation Method 1
nucleic acid concatemers, generated through strand-displacement amplification like rolling circle amplification
Data Source
AI summary
Provided are techniques for generating expression products using one or more nucleic acid concatemers that include tandem repeats of a nucleic acid sequence encoding the expression product or products. In one embodiment, different expression products may be co-expressed using a concatemer mixture of a first nucleic acid concatemer and a second nucleic acid concatemer having a predefined ratio to one another.