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Du F, Li Z, Li X, Zhang D, Zhang F, Zhang Z, Xu Y, Tang J, Li Y, Huang X, Gu Y, Sun X, Huang H. Optimizing multicopy chromosomal integration for stable high-performing strains. Nat Chem Biol 2024:10.1038/s41589-024-01650-0. [PMID: 38858530 DOI: 10.1038/s41589-024-01650-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2023] [Accepted: 05/15/2024] [Indexed: 06/12/2024]
Abstract
The copy number of genes in chromosomes can be modified by chromosomal integration to construct efficient microbial cell factories but the resulting genetic systems are prone to failure or instability from triggering homologous recombination in repetitive DNA sequences. Finding the optimal copy number of each gene in a pathway is also time and labor intensive. To overcome these challenges, we applied a multiple nonrepetitive coding sequence calculator that generates sets of coding DNA sequence (CDS) variants. A machine learning method was developed to calculate the optimal copy number combination of genes in a pathway. We obtained an engineered Yarrowia lipolytica strain for eicosapentaenoic acid biosynthesis in 6 months, producing the highest titer of 27.5 g l-1 in a 50-liter bioreactor. Moreover, the lycopene production in Escherichia coli was also greatly improved. Importantly, all engineered strains of Y. lipolytica, E. coli and Saccharomyces cerevisiae constructed with nonrepetitive CDSs maintained genetic stability.
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Affiliation(s)
- Fei Du
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Zijia Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Xin Li
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Duoduo Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Feng Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Zixu Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Yingshuang Xu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Jin Tang
- Research Institute of Intelligent Computing, Zhejiang Lab, Hangzhou, China
| | - Yongqian Li
- Research Institute of Intelligent Computing, Zhejiang Lab, Hangzhou, China
| | - Xingxu Huang
- Research Institute of Intelligent Computing, Zhejiang Lab, Hangzhou, China
- School of Life Science and Technology, ShanghaiTech University, Shanghai, China
| | - Yang Gu
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Xiaoman Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China.
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China.
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Lee Z, Wan J, Shen A, Barnard G. Gene copy number, gene configuration and LC/HC mRNA ratio impact on antibody productivity and product quality in targeted integration CHO cell lines. Biotechnol Prog 2024; 40:e3433. [PMID: 38321634 DOI: 10.1002/btpr.3433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2023] [Revised: 12/01/2023] [Accepted: 01/03/2024] [Indexed: 02/08/2024]
Abstract
The augmentation of transgene copy numbers is a prevalent approach presumed to enhance transcriptional activity and product yield. CHO cell lines engineered via targeted integration (TI) offer an advantageous platform for investigating the interplay between gene copy number, mRNA abundance, product yield, and product quality. Our investigation revealed that incrementally elevating the gene copy numbers of both IgG heavy chain (HC) and light chain (LC) concurrently resulted in the attainment of plateaus in mRNA levels and product titers, notably occurring beyond four to five gene copies integrated at the same TI site. Furthermore, maintaining a fixed gene copy number while varying the position of genes within the vector influenced the LC/HC mRNA ratio, which subsequently exerted a substantial impact on product titer. Moreover, manipulation of the LC/HC gene ratio through the introduction of surplus LC gene copies led to heightened LC mRNA expression and a reduction in the levels of high molecular weight species. It is noteworthy that the effects of excess LC on product titer were dependent on the specific molecule under consideration. The strategic utilization of PCR tags enabled precise quantification of transcription from each expression slot within the vector, facilitating the identification of highly expressive and less expressive slots. Collectively, these findings significantly enhance our understanding of stable antibody production in TI CHO cell lines.
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Affiliation(s)
- Zion Lee
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
| | - Jun Wan
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
| | - Amy Shen
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
| | - Gavin Barnard
- Department of Cell Culture and Bioprocess Operations, Genentech, Inc., San Francisco, California, USA
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