DHODH-Inactivated Cell Line for Toxicity-Free Clone Selection
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Solution Overview
Problem
Existing recombinant protein production systems face challenges in selecting high-producer clones due to the use of toxic selection markers like DHODH inhibitors (e.g., teriflunomide) or GS inhibitors (e.g., MSX), which pose safety and handling issues at large scales.
Innovation Solution
A cell line with a partially or fully inactivated endogenous DHODH gene is developed, allowing selection of protein-producing cells in a uridine-free medium using a culture system supplemented with uridine, and transfected with an expression vector encoding a mammalian DHODH, enabling high productivity without the need for toxic inhibitors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If toxic selection markers (DHODH inhibitors like teriflunomide or GS inhibitors like MSX) are used to select high-producer clones, then clone selection capability is improved, but safety and handling issues worsen at large scales
Solution Approach 1:
The patent removes the toxic selection marker component from the system by using a uridine auxotrophic cell line. Instead of adding toxic substances to select clones, the system extracts the selection mechanism to rely on the cell's inherent inability to synthesize uridine, thus eliminating the harmful factor while preserving clone selection capability
Solution Approach 2:
The cell line is engineered to be auxotrophic for uridine, meaning it cannot synthesize uridine on its own. This self-service mechanism allows the cell to naturally select for clones that have successfully integrated the expression vector containing the uridine biosynthesis pathway, eliminating the need for external toxic selection agents
2Measurement precision
If traditional selection markers are used to isolate high-producer clones, then expression screening capability is improved, but process complexity and time consumption worsen
Solution Approach 1:
The patent combines the selection marker function and the metabolic pathway function into a single integrated system. The expression vector simultaneously provides both the uridine biosynthesis pathway (for selection) and the recombinant protein expression capability, merging two functions into one component and simplifying the overall process
Solution Approach 2:
The expression vector is designed to serve multiple functions: it acts as both a selection marker (by providing uridine biosynthesis capability in a auxotrophic background) and a protein expression vehicle. This multi-functionality reduces the number of separate components needed and simplifies the selection and screening process
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 increases cell viability and productivity by avoiding the use of toxic selection pressures, demonstrating high recombinant protein production capabilities.
Implementation Method 1
DHODH is an enzyme required for pyrimidine synthesis. Compounds which inhibit DHODH therefore inhibit DNA synthesis and hence cell proliferation.
Data Source
AI summary
The present invention concerns a cell line comprising an endogenous dehydroorotate dehydrogenase (DHODH) gene which is partially or fully inactivated, and its use for producing recombinant proteins.