Mutator Genes Enhance Genetic Diversity in CHO Cells

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Solution Overview

Problem

Current methods for directed evolution of organisms lack the ability to efficiently increase genetic diversity and select desired hereditary traits, as they do not effectively modify the mutation rate during DNA replication.

Innovation Solution

Introducing mutator genes with low fidelity and exonuclease deficient mutations into CHO cells, specifically the D398A and L602M substitutions in the DNA polymerase delta gene, to increase the mutation rate and facilitate the selection of desired traits under selective conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the mutation rate is increased by introducing mutator genes, then genetic diversity is enhanced, but the stability of the organism's genome is reduced

Engineering Contradiction:
Improvegenetic diversityVSAvoidgenome stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The patent applies preliminary action by introducing mutator genes into the CHO cell population before the directed evolution process begins. This pre-establishment of increased mutation capability allows the population to generate genetic diversity on demand during subsequent selection rounds, rather than attempting to induce mutations during the selection process itself. The mutator genes are integrated into the genome beforehand, creating a controlled mechanism for generating variation that can be activated when needed.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent applies parameter changes by modifying the mutation rate parameter of the CHO cell population through the introduction of mutator genes with specific mutations (exonuclease deficient and low fidelity). This changes the fundamental parameter of DNA replication accuracy, allowing the system to generate higher genetic diversity while maintaining control over the mutation process through the specific characteristics of the introduced mutator genes.

Inventive Principle:
Principle #35Parameter changes

2Productivity

If mutator genes are introduced to increase mutation rate, then selection of desired traits is facilitated, but the complexity of the genetic modification process increases

Engineering Contradiction:
Improveselection efficiencyVSAvoidgenetic modification complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent applies segmentation by dividing the mutator gene introduction process into distinct functional components: exonuclease deficient mutations and low fidelity mutations. These segmented mutation types work together to produce the desired effect of increased genetic diversity. The segmentation allows for controlled introduction of specific mutation mechanisms rather than attempting to introduce a single complex mutator gene.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent applies the intermediary principle by using mutator genes as intermediary elements that mediate between the standard DNA replication process and the desired increased genetic diversity. The mutator genes act as intermediaries that alter the replication fidelity in a controlled manner, enabling the selection process to access a broader range of genetic variants without directly manipulating the entire genome.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If the mutation rate is modified during DNA replication, then hereditary trait variation increases, but the reliability of DNA replication is reduced

Engineering Contradiction:
Improvehereditary trait variationVSAvoidDNA replication reliability
Core Design Contradiction:
Quantity of substanceVSReliability

Solution Approach 1:

The patent applies dynamics by making the DNA replication reliability dynamic rather than static. Through the introduction of inducible or controllable mutator genes, the system can adjust the replication fidelity level based on the needs of the directed evolution process. When genetic diversity is needed, the mutator genes increase the mutation rate; when stability is needed, the system can revert to normal replication fidelity, creating a dynamic control mechanism for replication reliability.

Inventive Principle:
Principle #15Dynamics

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 significantly enhances genetic diversity, allowing for the efficient selection of organisms with desired traits, such as resistance to pathogens or improved product production, by growing cells with modified mutation rates under specific conditions.

Implementation Method 1

Modifying the mutation rate during DNA replication may increase the genetic diversity within and among individual organisms in a population

Methodology Applied
Scientific EffectDNA replication:

Implementation Method 2

the introduction of the at least one mutator gene increases the mutation rate of the CHO cell

Methodology Applied
Scientific EffectMutation:

Data Source

PatentEP2285956B1Method of directing the evolution of an organism
Publication Date: 2016.05.18 CHITOSE LAB
  • EP2285956B1 patent drawingFigure 1A~1B
  • EP2285956B1 patent drawingFigure 2
  • EP2285956B1 patent drawingFigure 3

AI summary

The present disclosure relates to a method of directing the evolution of an organism by modifying the mutation rate of an organism. The increase in genetic diversity may be used to facilitate the selection of a desired hereditary trait in an organism.