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Liu X, Chen Q, Yin X, Wang X, Ran J, Yu W, Wang B. Study on chromatin regulation patterns of expression vectors in the PhiC31 integration site. Epigenetics 2024; 19:2337085. [PMID: 38595049 PMCID: PMC11008548 DOI: 10.1080/15592294.2024.2337085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2023] [Accepted: 03/26/2024] [Indexed: 04/11/2024] Open
Abstract
The PhiC31 integration system allows for targeted and efficient transgene integration and expression by recognizing pseudo attP sites in mammalian cells and integrating the exogenous genes into the open chromatin regions of active chromatin. In order to investigate the regulatory patterns of efficient gene expression in the open chromatin region of PhiC31 integration, this study utilized Ubiquitous Chromatin Opening Element (UCOE) and activating RNA (saRNA) to modulate the chromatin structure in the promoter region of the PhiC31 integration vector. The study analysed the effects of DNA methylation and nucleosome occupancy changes in the integrated promoter on gene expression levels. The results showed that for the OCT4 promoter with moderate CG density, DNA methylation had a smaller impact on expression compared to changes in nucleosome positioning near the transcription start site, which was crucial for enhancing downstream gene expression. On the other hand, for the SOX2 promoter with high CG density, increased methylation in the CpG island upstream of the transcription start site played a key role in affecting high expression, but the positioning and clustering of nucleosomes also had an important influence. In conclusion, analysing the DNA methylation patterns, nucleosome positioning, and quantity distribution of different promoters can determine whether the PhiC31 integration site possesses the potential to further enhance expression or overcome transgene silencing effects by utilizing chromatin regulatory elements.
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Affiliation(s)
- Xueli Liu
- Key Technology Engineering Center for New Veterinary Vaccine and Industry of Yunnan Provincial Education Department, Kunming University, Kunming, Yunnan, China
- Pharmaceutical Department, Second Affiliated Hospital of Xinxiang Medical University, Xinxiang, Henan, China
| | - Qina Chen
- Key Technology Engineering Center for New Veterinary Vaccine and Industry of Yunnan Provincial Education Department, Kunming University, Kunming, Yunnan, China
| | - Xudong Yin
- Key Technology Engineering Center for New Veterinary Vaccine and Industry of Yunnan Provincial Education Department, Kunming University, Kunming, Yunnan, China
| | - Xiao Wang
- Key Technology Engineering Center for New Veterinary Vaccine and Industry of Yunnan Provincial Education Department, Kunming University, Kunming, Yunnan, China
| | - Jinshan Ran
- Key Technology Engineering Center for New Veterinary Vaccine and Industry of Yunnan Provincial Education Department, Kunming University, Kunming, Yunnan, China
| | - Wei Yu
- Department of Pharmacy, 920th Hospital of Joint Logistics Support Force, PLA, Kunming, China
| | - Bin Wang
- Key Technology Engineering Center for New Veterinary Vaccine and Industry of Yunnan Provincial Education Department, Kunming University, Kunming, Yunnan, China
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Geng SL, Zhao XJ, Zhang X, Zhang JH, Mi CL, Wang TY. Recombinant therapeutic proteins degradation and overcoming strategies in CHO cells. Appl Microbiol Biotechnol 2024; 108:182. [PMID: 38285115 PMCID: PMC10824870 DOI: 10.1007/s00253-024-13008-6] [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: 11/06/2023] [Revised: 12/20/2023] [Accepted: 01/08/2024] [Indexed: 01/30/2024]
Abstract
Mammalian cell lines are frequently used as the preferred host cells for producing recombinant therapeutic proteins (RTPs) having post-translational modified modification similar to those observed in proteins produced by human cells. Nowadays, most RTPs approved for marketing are produced in Chinese hamster ovary (CHO) cells. Recombinant therapeutic antibodies are among the most important and promising RTPs for biomedical applications. One of the issues that occurs during development of RTPs is their degradation, which caused by a variety of factors and reducing quality of RTPs. RTP degradation is especially concerning as they could result in reduced biological functions (antibody-dependent cellular cytotoxicity and complement-dependent cytotoxicity) and generate potentially immunogenic species. Therefore, the mechanisms underlying RTP degradation and strategies for avoiding degradation have regained an interest from academia and industry. In this review, we outline recent progress in this field, with a focus on factors that cause degradation during RTP production and the development of strategies for overcoming RTP degradation. KEY POINTS: • The recombinant therapeutic protein degradation in CHO cell systems is reviewed. • Enzymatic factors and non-enzymatic methods influence recombinant therapeutic protein degradation. • Reducing the degradation can improve the quality of recombinant therapeutic proteins.
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Affiliation(s)
- Shao-Lei Geng
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Xiao-Jie Zhao
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Xi Zhang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- School of Pharmacy, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Ji-Hong Zhang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Chun-Liu Mi
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, Henan, China
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China
| | - Tian-Yun Wang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
- School of Basic Medical Sciences, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
- Henan Engineering Research Center for Biopharmaceutical Innovation, Xinxiang Medical University, Xinxiang, 453003, Henan, China.
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