Human Ribosomal Promoter Enhances Mammalian Protein Expression

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Solution Overview

Problem

Current methods for producing pharmaceutical proteins in cultured mammalian cells, such as CHO cells, face challenges including low growth rates, low productivity, and high production costs, necessitating the development of more effective promoters to enhance foreign gene expression and reduce production costs.

Innovation Solution

A promoter polynucleotide sequence starting approximately 2 kbp upstream of the transcription start site of human ribosomal protein genes, such as RPS7, RPL32, or RPL34, is used to create a foreign gene expression unit that significantly enhances protein production in mammalian cells, potentially reducing production costs by improving expression levels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a cultured mammalian cell expression system is used to produce pharmaceutical proteins, then post-translational modification can be performed and biological activity can be achieved, but the growth rate is low and productivity is low

Engineering Contradiction:
Improvebiological activityVSAvoidgrowth rate
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent changes the key parameter of promoter activity to enhance transcriptional efficiency. By using a human ribosomal protein gene promoter instead of conventional promoters, the system achieves higher foreign gene expression levels while maintaining the essential post-translational modification capabilities of mammalian cells.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a cultured mammalian cell expression system is used to produce pharmaceutical proteins, then post-translational modification can be performed, but the production cost is high

Engineering Contradiction:
Improvepost-translational modificationVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent creates an optimized transcriptional environment by using a human-specific promoter that is naturally recognized by human cell transcription machinery. This reduces the metabolic burden on the host cell and improves translation efficiency, thereby reducing overall production costs while maintaining essential post-translational modifications.

Inventive Principle:
Principle #39Inert atmosphere (Inert environment)

3Ease of operation

If the CMV promoter is used in CHO cells to express foreign genes, then foreign gene expression can be achieved, but the promoter activity is insufficient for high-level production

Engineering Contradiction:
Improveforeign gene expressionVSAvoidpromoter activity
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The patent fundamentally changes the promoter parameter from viral origin (CMV) to human genomic origin (ribosomal protein gene). This human promoter exhibits higher activity in CHO cells because it is naturally compatible with human transcription factors and chromatin structure, achieving superior foreign gene expression levels.

Inventive Principle:
Principle #35Parameter changes

4Ease of manufacture

If protein production amount is increased to reduce production costs, then productivity must be improved, but conventional promoters cannot achieve sufficient expression levels

Engineering Contradiction:
Improveproduction costVSAvoidproduction amount
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent optimizes the transcriptional parameter by selecting a human ribosomal protein gene promoter that naturally drives high-level expression in mammalian cells. This promoter enhancement directly increases production amount, which in turn reduces production cost per unit of protein without requiring changes to other process parameters.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP2787080B1Promoter derived from human gene
Publication Date: 2018.03.21 DAIICHI SANKYO CO LTD
  • EP2787080B1 patent drawingFigure 1
  • EP2787080B1 patent drawingFigure 2
  • EP2787080B1 patent drawingFigure 3

AI summary

The present invention relates to a transfected mammalian host cell whose ability to secrete a foreign protein has been enhanced by using a foreign gene expression vector having a promoter derived from a human gene, and a method for producing the foreign protein using the host cell. A method for enhancing the production of a foreign protein to be used in a pharmaceutical protein product in a host cell such as a cultured mammalian cell is provided. A promoter derived from a human gene having a promoter activity higher than that of a cytomegalovirus (CMV) promoter in a host cell such as a cultured mammalian cell is provided.