ASNS-Auxotrophic Mammalian Cell Lines for Multi-Vector Selection

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Solution Overview

Problem

Existing biomanufacturing technologies lack efficient multiple selection methods for introducing multiple vectors into mammalian cell lines, particularly for producing bispecific antibodies and other multichain proteins, necessitating the development of cell lines with reduced or eliminated expression of key biosynthesis components like ASNS and GS to facilitate exogenous asparagine supply.

Innovation Solution

Engineering mammalian cell lines with reduced or eliminated expression of the ASNS and optionally GS genes using targeted endonuclease-mediated genome editing, such as CRISPR RNP complexes or zinc finger nucleases, to create asparagine auxotrophic cell lines that require exogenous asparagine, enabling multiple selection systems for enhanced protein expression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple selection methods are implemented to introduce multiple vectors into mammalian cell lines, then the ability to produce bispecific antibodies and multichain proteins is improved, but the complexity of the cell line engineering and selection process increases

Engineering Contradiction:

Improvemultiple selection methodsVSAvoidcell line engineering complexity

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the endogenous ASNS gene from mammalian cell lines to create an asparagine auxotrophic selection system. This provides a new, independent selection method that operates through a different metabolic pathway from traditional systems like GS or DHFR, enabling multiple simultaneous selection methods without proportionally increasing engineering complexity

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The ASNS knockout cell line provides a universal selection platform that can be combined with existing selection systems (GS, DHFR, antibiotic resistance) to enable simultaneous selection of multiple vectors. The asparagine auxotrophic selection mechanism works independently of other common selection pathways, providing multi-functionality across different protein production applications

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Reliability

If endogenous ASNS expression is reduced or eliminated to create asparagine auxotrophic cell lines, then selection efficiency for multiple vectors is improved, but the metabolic burden on cells increases

Engineering Contradiction:

Improveselection efficiencyVSAvoidmetabolic burden

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent introduces exogenous asparagine into the culture medium as an intermediary substance that compensates for the eliminated endogenous ASNS pathway. This external asparagine supply acts as a mediator, providing the necessary amino acid for cell growth and protein synthesis without requiring functional ASNS enzyme activity, thereby maintaining cell health while enabling efficient selection

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the nutritional parameter of the culture system by controlling asparagine availability in the medium. By adjusting asparagine concentration, the system enables selective pressure for vector integration while maintaining cell viability. The selection efficiency is tuned through parameter optimization of asparagine levels rather than complete pathway elimination

Inventive Principle:

Principle #35Parameter changes

3Manufacturing precision

If targeted endonuclease-mediated genome editing is used to inactivate ASNS, then precision of gene knockout is improved, but the risk of off-target effects and genomic instability increases

Engineering Contradiction:

Improvegene knockout precisionVSAvoidoff-target effects

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent segments the genome editing process into controlled steps using CRISPR RNP complexes or zinc finger nucleases with specifically designed guide sequences. The targeting mechanism is divided into modular components (guide RNA/nuclease or zinc finger domains) that can be precisely configured to recognize only the intended ASNS target sequence, minimizing off-target binding and effects

Inventive Principle:

Principle #1Segmentation

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

Facilitates the production of recombinant proteins like bispecific antibodies by providing cell lines with improved selection efficiency and productivity, allowing for stable expression of effector proteins and maintaining cell viability and health.

Implementation Method 1

The chromosomal ASNS sequence can be inactivated using targeting endonuclease-mediated genome modification, e.g., CRISPR ribonucleoprotein (RNP) complexes or zinc finger nucleases

Methodology Applied

Scientific EffectCRISPR RNP complex-mediated genome editing:

Data Source

PatentUS20260028611A1Metabolic selection via asparagine biosynthesis pathway

Publication Date: 2026.01.29 EMD MILLIPORE CORP

AI summary

The present disclosure provides an isolated mammalian cell comprising a reduced or eliminated expression of Asparagine Synthetase (ASNS). Further provided are methods for preparing such cells and methods for using such cells for the production of recombinant proteins.