Bacterial Packaging Strains for Stable rdsRNA Production
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Solution Overview
Problem
Current recombinant double-stranded RNA phage (rdsRP) systems are unstable and not suitable for large-scale manufacturing or use in eukaryotic cells, lacking guidance on generating and isolating stable carrier strains that harbor and replicate rdsRNs, and previous methods are unclear on how to launch rdsRNs de novo or separate them from wild-type dsRPs.
Innovation Solution
Development of bacterial packaging strains that include sequences encoding dsRNA phage procapsids and a selectable phenotypic mutation, allowing for the selection and maintenance of recombinant double-stranded RNA nucleocapsids (rdsRNs) that encode functional genes, which can be used to produce and deliver RNA of interest to eukaryotic cells, including vaccine antigens and immunomodulatory proteins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If recombinant double-stranded RNA phage (rdsRP) systems are used for gene expression, then RNA of interest can be delivered to eukaryotic cells, but the systems are unstable and not suitable for large-scale manufacturing
Solution Approach 1:
The invention divides the rdsRP system into two separate components: (1) a bacterial packaging strain that contains the dsRNA phage genome and produces nucleocapsids, and (2) a separate recombinant ssRNA segment encoding the gene of interest. This segmentation allows the stable maintenance of the packaging system in bacteria while enabling flexible production of different recombinant RNAs, thereby resolving the contradiction between stability and manufacturing capability.
Solution Approach 2:
The invention introduces a bacterial packaging strain as an intermediary system that bridges the gap between stable dsRNA phage maintenance and flexible recombinant RNA production. The packaging strain contains all necessary components (polymerase, nucleocapsid proteins, packaging signals) to process and package recombinant ssRNA segments into infectious rdsRNs, enabling stable yet scalable production.
2Ease of manufacture
If previous rdsRP methods are used, then some RNA production is achieved, but there is no clear guidance on generating and isolating stable carrier strains that harbor and replicate rdsRNs
Solution Approach 1:
The invention performs preliminary action by pre-construction of stable bacterial packaging strains that contain the complete dsRNA phage genome and are capable of maintaining and replicating rdsRNs. These pre-engineered packaging strains serve as reliable carrier systems that can be readily used for producing various recombinant RNAs, eliminating the need for de novo strain construction for each application.
3Ease of manufacture
If wild-type dsRPs are used, then packaging activity is available, but it is unclear how to separate recombinant rdsRNs from wild-type dsRPs
Solution Approach 1:
The invention applies local quality by introducing specific distinguishing features into the recombinant RNA segments, such as unique packaging signals, sequence tags, or size differences, that allow selective identification and separation from wild-type dsRPs. This enables purification of recombinant rdsRNs through methods like density gradient centrifugation or affinity-based separation.
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 stable replication and production of rdsRNs in bacterial strains, facilitating their use in eukaryotic cells for immune response induction and biological effects, improving stability and safety compared to previous rdsRP systems.
Implementation Method 1
Synthesis of positive-strand RNA (herein 'mRNA') occurs within the nucleocapsid and is carried out by RNA-dependent RNA polymerase encoded in part by gene-2 on segment-L
Implementation Method 2
The proteins produced by segment-L are mainly associated with procapsid production
Data Source
AI summary
Bacterial packaging strains useful for generating recombinant double-stranded RNA nucleocapsids (rdsRNs) are provided. The packaging strains are useful for the production of RNA encoding vaccine antigens, bioactive proteins, immunoregulatory proteins, antisense RNAs, and catalytic RNAs in eukaryotic cells or tissues. Recombinant ssRNA is introduced into the strains and packaged to form rdsRNs de novo.