Codon-Optimized FSH Nucleic Acid Sequences for CHO Cell Expression
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Solution Overview
Problem
Current methods for producing recombinant human FSH in CHO cells result in suboptimal yield and expression rates, limiting the quantity of FSH that can be produced, due to mismatched codon usage between the wild-type DNA sequences and CHO cells.
Innovation Solution
Modification of nucleic acid sequences coding for the α- and β-chains of human FSH to align with the codon usage in CHO cells, significantly increasing FSH production by optimizing translation efficiency through the use of preferred codons, as depicted in modified sequences provided in SEQ ID Nos. 1 and 2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If wild-type human FSH nucleic acid sequences are used in CHO cells, then the natural amino acid sequence is maintained, but the expression level and production yield are suboptimal due to codon usage mismatch
Solution Approach 1:
The nucleic acid sequences coding for the α- and β-chains of human FSH were modified by changing codon usage parameters to match CHO cell preferences. Specifically, rare codons in the wild-type sequences were replaced with preferred codons for CHO cells, while maintaining the same amino acid sequences. This parameter change in codon frequency and distribution resolved the contradiction by enabling more efficient translation and achieving both high yield and consistent expression.
2Productivity
If codon optimization is performed to increase FSH production, then translation efficiency improves, but the nucleic acid sequence diverges from the wild-type sequence
Solution Approach 1:
Codon optimization was applied locally at the nucleic acid sequence level without altering the protein-coding information. Each codon was individually evaluated and replaced based on CHO cell codon usage tables, allowing the sequence to be locally adapted to host cell preferences while maintaining global functional integrity. This local modification approach enabled high productivity while preserving the essential amino acid sequence fidelity.
Data Source
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AI summary
The present invention relates to nucleic acid molecules comprising a nucleic acid sequence coding for the α- and the β-chain of the human follicle stimulating hormone (FSH), respectively, which has been modified with respect to the codon usage in CHO cells. The present invention further relates to a recombinant nucleic acid molecule comprising such nucleic acid sequences and host cells containing such recombinant nucleic acid molecules, as well as their use in the production of recombinant human FSH. Finally, the present invention also relates to a method for producing host cells expressing human follicle stimulating hormone by transfecting cells in suspension culture under serum- free conditions with the recombinant nucleic acid molecule of the present invention.