Super-Enhancer Targeted Integration for Stable CHO Cell Expression
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Solution Overview
Problem
Current recombinant protein production from CHO cells faces challenges such as low protein quantity and genetic instability due to random integration of transgenes, leading to unstable expression and quality issues.
Innovation Solution
Targeted integration of exogenous nucleic acid molecules into super-enhancer sequences within the CHO cell genome to achieve high-level and stable expression of recombinant proteins, utilizing CRISPR/Cas9 or other genome editing methods to site-specifically place the transgene near or within these super-enhancer regions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If multiple copies of expression cassette are introduced into CHO cells to increase protein production, then protein quantity increases, but genetic stability deteriorates due to recombination between similar sequences
Solution Approach 1:
The patent applies local quality by creating heterogeneity among multiple expression cassettes through sequence diversification. Each cassette contains the same functional elements (promoter, coding sequence, terminator) but differs in non-coding regions such as introns, 5'UTR, or 3'UTR sequences. This local differentiation prevents homologous recombination between cassettes while maintaining identical protein expression functionality, thereby resolving the contradiction between increasing protein quantity and maintaining genetic stability.
2Ease of manufacture
If random integration of transgene is used for simplicity, then ease of manufacture improves, but expression stability deteriorates due to unpredictable integration sites
Solution Approach 1:
The patent applies preliminary action by pre-identifying and characterizing super-enhancer regions in the CHO cell genome before transgene integration. These regions are selected based on their known ability to drive high-level gene expression. By preparing these target sites in advance and using targeted integration methods (such as CRISPR/Cas9 or homology-directed repair), the patent ensures that transgenes are consistently integrated into optimal locations, thereby achieving both ease of manufacture through standardized protocols and high expression stability.
3Quantity of substance
If high copy number of expression cassette is introduced to maximize protein expression, then protein quantity increases, but molecular machinery overload occurs leading to decreased expression rate
Solution Approach 1:
The patent applies parameter changes by modifying the quality parameters of expression cassettes rather than simply increasing quantity. Through sequence diversification in non-coding regions, the patent enables the cell to accommodate multiple cassettes without triggering recombination or overwhelming the molecular machinery. This parameter modification (sequence heterogeneity) allows for higher total protein production while maintaining optimal expression rates per cassette, effectively resolving the contradiction between quantity and productivity.
Data Source
AI summary
Abstract: The present invention belongs to the field of biotechnology, and specifically relates to recombinant gene expression. The invention concerns a method of recombinant gene expression from a Chinese Hamster Ovary (CHO) cell, by using super-enhancer sequences for increased gene expression. Thus, the invention provides a method for producing an engineered CHO cell by introducing into the cell an exogenous nucleic acid molecule into or within 500 kb upstream or downstream of a super-enhancer as expression-enhancing sequence. The invention further provides an engineered CHO cell produced by the method. The invention further provides a method of producing a recombinant polypeptide. The invention is further directed to the use of a super-enhancer for transgene expression.