Mammalian GPCR Expression Vector with Inducible Promoter
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Solution Overview
Problem
Current methods for expressing G protein-coupled receptors (GPCRs) in mammalian cells result in low expression levels, making structural and functional studies, drug design, and antibody production challenging due to cellular toxicity, inefficient folding, and incorrect post-translational modifications in alternative expression systems.
Innovation Solution
Development of mammalian cell lines using vectors with a cytomegalovirus (CMV) promoter, signal peptide, epitope tag, Kozak sequence, and viral origin of replication to achieve high expression levels of GPCR proteins, up to 1 million copies per cell, facilitating structural and functional studies, and enabling the production of therapeutic candidates and antibodies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional expression systems (bacteria, yeast, baculovirus) are used to express GPCRs, then the expression system can be established, but the expression level is insufficient and folding or post-translational modification is incorrect
Solution Approach 1:
The patent changes the expression system from conventional systems (bacteria, yeast, baculovirus) to mammalian cell lines, fundamentally altering the biological parameters of the expression system. This enables correct folding and post-translational modification while achieving high expression levels of GPCRs.
Solution Approach 2:
The patent uses viral vectors (retrovirus, lentivirus, adenovirus, adenassociated virus) to copy and deliver the GPCR gene into mammalian cell lines, enabling stable integration and high-level expression. The viral vectors serve as templates to replicate the GPCR gene within the host cell genome.
2Quantity of substance
If mammalian cell lines are used to express GPCRs at high levels, then expression level increases to over one million copies per cell, but cellular toxicity occurs
Solution Approach 1:
The patent employs partial action by using inducible promoters (tet-on, tet-off, doxycycline-responsive promoters) that allow controlled expression of the GPCR gene. This enables high expression levels when needed while allowing suppression to prevent cellular toxicity during culture maintenance.
Solution Approach 2:
The patent introduces dynamic control mechanisms through inducible promoters and selectable markers that allow the expression system to adapt between high-expression mode (for research) and low-expression mode (for cell health). The system transitions dynamically based on experimental requirements.
3Reliability
If endogenous GPCR expression is used in mammalian cells, then cellular functioning is maintained, but expression level is too low for structural and functional studies
Solution Approach 1:
The patent segments the GPCR expression function from endogenous cellular processes by using exogenous viral vectors to deliver and express the GPCR gene separately. This allows independent optimization of expression levels without disrupting normal cellular functioning, as the exogenous expression system operates parallel to endogenous processes.
Solution Approach 2:
The patent introduces viral vectors as intermediary carriers that deliver the GPCR gene into mammalian cells. These vectors act as mediators between the external research environment and the cellular expression machinery, enabling high-level expression while maintaining cellular homeostasis through controlled integration and expression.
Data Source
AI summary
The present invention provides expression vectors that facilitate high levels of expression of GPCR proteins. Encompassed by the invention are methods and compositions for recombinant cell lines expressing GPCR proteins with the aid of the expression vectors of the instant invention. The recombinant cell lines of the instant invention express GPCR proteins at levels of at least about 150,000 copies of the protein per cell. The present invention also provides methods and compositions for raising antibodies against GPCR proteins using the high expressing recombinant cells of the instant invention.