1
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Wang XY, Zhang WL, Zhang X, Fu YS, Wang HM, Sun QL, Li Q, Jia YL, Zhang JH, Wang TY. Combination of MAR and intron increase transgene expression of episomal vectors in CHO cells. Biotechnol J 2023; 18:e2200643. [PMID: 37551822 DOI: 10.1002/biot.202200643] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 07/22/2023] [Accepted: 08/03/2023] [Indexed: 08/09/2023]
Abstract
Previous work has shown that the EF-1α promoter of episomal vectors maintains high-level transgene expression in stably transfected Chinese hamster ovary (CHO) cells. However, the transgene expression levels need to be further increased. Here, we first incorporated matrix attachment regions (MARs), ubiquitous chromatin opening element (UCOE), stabilizing anti repressor elements 40 (STAR 40) elements into episomal vector at different sites and orientations, and systemically assessed their effects on transgene expression in transfected CHO-K1 cells. Results showed that enhanced green fluorescent protein (eGFP) expression levels increased remarkably when MAR X-29 was inserted upstream of the promoter, followed by the insertion of MAR1 downstream of the poly A, and the orientation had no significant effect. Moreover, MAR X-29 combined with human cytomegalovirus intron (hCMVI) yielded the highest transgene expression levels (4.52-fold). Transgene expression levels were not exclusively dependent on transgene copy numbers and were not related to the mRNA expression level. In addition, vector with MAR X-29+hCMVI can induce herpes simplex virus thymidine kinase (HSV-TK) protein expression, and the HSV-TK protein showed a cell-killing effect and an obvious bystander effect on HCT116 cells. In conclusion, the combination of MAR X-29 and hCMV intron can achieve high efficiency transgene expression mediated by episomal vectors in CHO-K1 cells.
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Affiliation(s)
- Xiao-Yin Wang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Wei-Li Zhang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
- Center for Medical Genetics, Nanyang Second General Hospital, Nanyang, China
| | - Xi Zhang
- College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Yu-Shun Fu
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Hao-Min Wang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Qiu-Li Sun
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Qin Li
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
| | - Yan-Long Jia
- College of Pharmacy, Xinxiang Medical University, Xinxiang, China
| | - Jun-He Zhang
- Institutes of Health Central Plains, Xinxiang Medical University, Xinxiang, China
| | - Tian-Yun Wang
- School of Basic Medical Science, Xinxiang Medical University, Xinxiang, China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
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2
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Zhang J, Wang TY, Zhang C, Mi C, Geng S, Tang Y, Wang X. CMV/AAT promoter of MAR-based episomal vector enhanced transgene expression in human hepatic cells. 3 Biotech 2023; 13:354. [PMID: 37810190 PMCID: PMC10558423 DOI: 10.1007/s13205-023-03774-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2023] [Accepted: 09/13/2023] [Indexed: 10/10/2023] Open
Abstract
We have previously developed a non-viral episomal vector based on matrix attachment region (MAR) that can facilitate plasmid replication episomally in mammal cells. In this study, we have focused on the development of an alternative tissue specific episomal vector by incorporating into cis-acting elements. We found that AAT promoter demonstrated the highest eGFP expression level in HepG2, Huh-7 and HL-7702 hepatic cells. Furthermore, hCMV enhancer when combined with AAT promoter significantly improved the eGFP expression level in the transfected HepG2 cells. The mean fluorescence intensity of eGFP in hCMV2 group was 1.33 fold, which was higher than that of the control (p < 0.01), followed by the hCMV1 group (1.21 fold). In addition, the percentages of eGFP-expressing cells in hCMV1 and hCMV2 groups were observed to be 49.3% and 57.2%, which were significantly higher than that of the enhancer-devoid control vector (44.3%) (p < 0.05). Moreover, the eGFP protein were up to 3.5 fold and 5.1 fold (p < 0.05), respectively. This observation could be related with the activities of some specific transcription factors (TFs) during the transcriptional process, such as SRF, REL and CREB1. The composite CMV/AAT promoter can be thus used for efficient transgene expression of MAR-based episomal vector in liver cells and as a potential gene transfer tools for the management of liver diseases. Supplementary Information The online version contains supplementary material available at 10.1007/s13205-023-03774-x.
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Affiliation(s)
- Jihong Zhang
- School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan Province China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Tian-Yun Wang
- School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan Province China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Chunbo Zhang
- College of Life Science, Henan Normal University, Xinxiang, 453000 China
| | - Chunliu Mi
- School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan Province China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Shaolei Geng
- School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan Province China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Yuanyuan Tang
- School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan Province China
| | - Xiaoyin Wang
- School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan Province China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
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3
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Bachhav B, de Rossi J, Llanos CD, Segatori L. Cell factory engineering: Challenges and opportunities for synthetic biology applications. Biotechnol Bioeng 2023; 120:2441-2459. [PMID: 36859509 PMCID: PMC10440303 DOI: 10.1002/bit.28365] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2022] [Revised: 02/14/2023] [Accepted: 02/27/2023] [Indexed: 03/03/2023]
Abstract
The production of high-quality recombinant proteins is critical to maintaining a continuous supply of biopharmaceuticals, such as therapeutic antibodies. Engineering mammalian cell factories presents a number of limitations typically associated with the proteotoxic stress induced upon aberrant accumulation of off-pathway protein folding intermediates, which eventually culminate in the induction of apoptosis. In this review, we will discuss advances in cell engineering and their applications at different hierarchical levels of control of the expression of recombinant proteins, from transcription and translational to posttranslational modifications and subcellular trafficking. We also highlight challenges and unique opportunities to apply modern synthetic biology tools to the design of programmable cell factories for improved biomanufacturing of therapeutic proteins.
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Affiliation(s)
- Bhagyashree Bachhav
- Department of Chemical and Biochemical Engineering, Rice University, Houston, United States
| | - Jacopo de Rossi
- Systems, Synthetic, and Physical Biology, Rice University, Houston, United States
| | - Carlos D. Llanos
- Systems, Synthetic, and Physical Biology, Rice University, Houston, United States
| | - Laura Segatori
- Department of Chemical and Biochemical Engineering, Rice University, Houston, United States
- Systems, Synthetic, and Physical Biology, Rice University, Houston, United States
- Department of Bioengineering, Rice University, Houston, United States
- Department of Biosciences, Rice University, Houston, United States
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4
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Razin SV, Zhegalova IV, Kantidze OL. Domain Model of Eukaryotic Genome Organization: From DNA Loops Fixed on the Nuclear Matrix to TADs. BIOCHEMISTRY. BIOKHIMIIA 2022; 87:667-680. [PMID: 36154886 DOI: 10.1134/s0006297922070082] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/20/2022] [Revised: 06/18/2022] [Accepted: 06/22/2022] [Indexed: 06/16/2023]
Abstract
The article reviews the development of ideas on the domain organization of eukaryotic genome, with special attention on the studies of DNA loops anchored to the nuclear matrix and their role in the emergence of the modern model of eukaryotic genome spatial organization. Critical analysis of results demonstrating that topologically associated chromatin domains are structural-functional blocks of the genome supports the notion that these blocks are fundamentally different from domains whose existence was proposed by the domain hypothesis of eukaryotic genome organization formulated in the 1980s. Based on the discussed evidence, it is concluded that the model postulating that eukaryotic genome is built from uniformly organized structural-functional blocks has proven to be untenable.
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Affiliation(s)
- Sergey V Razin
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia.
- Faculty of Biology, Lomonosov Moscow State University, Moscow, 119991, Russia
| | - Irina V Zhegalova
- Skolkovo Institute of Science and Technology, Moscow, 121205, Russia
- Faculty of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119991, Russia
- Kharkevich Institute for Information Transmission Problems, Moscow, 127051, Russia
| | - Omar L Kantidze
- Institute of Gene Biology, Russian Academy of Sciences, Moscow, 119334, Russia
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5
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Li Q, Yan RF, Yang YX, Mi CL, Jia YL, Wang TY. Stabilizing and Anti-Repressor Elements Effectively Increases Transgene Expression in Transfected CHO Cells. Front Bioeng Biotechnol 2022; 10:840600. [PMID: 35721852 PMCID: PMC9199445 DOI: 10.3389/fbioe.2022.840600] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 04/21/2022] [Indexed: 11/13/2022] Open
Abstract
Chinese hamster ovary (CHO) cells are currently the most widely used host cells for recombinant therapeutic protein (RTP) production. Currently, the RTP yields need to increase further to meet the market needs and reduce costs. In this study, three stabilizing and anti-repressor (SAR) elements from the human genome were selected, including human SAR7, SAR40, and SAR44 elements. SAR elements were cloned upstream of the promoter in the eukaryotic vector, followed by transfection into CHO cells, and were screened under G418 pressure. Flow cytometry was used to detect enhanced green fluorescent protein (eGFP) expression levels. The gene copy numbers and mRNA expression levels were determined through quantitative real-time PCR. Furthermore, the effect of the stronger SAR elements on adalimumab was investigated. The results showed that transgene expression levels in the SAR-containing vectors were higher than that of the control vector, and SAR7 and SAR40 significantly increased and maintained the long-term expression of the transgene in CHO cells. In addition, the transgene expression level increase was related with gene copy numbers and mRNA expression levels. Collectively, SAR elements can enhance the transgene expression and maintain the long-term expression of a transgene in transfected CHO cells, which may be used to increase recombinant protein production in CHO cells.
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Affiliation(s)
- Qin Li
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Rui-Fang Yan
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China
| | - Yong-Xiao Yang
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Chun-Liu Mi
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Yan-Long Jia
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
| | - Tian-Yun Wang
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, China
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6
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Soni AP, Lee J, Shin K, Koiwa H, Hwang I. Production of Recombinant Active Human TGFβ1 in Nicotiana benthamiana. FRONTIERS IN PLANT SCIENCE 2022; 13:922694. [PMID: 35712604 PMCID: PMC9197560 DOI: 10.3389/fpls.2022.922694] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2022] [Accepted: 05/11/2022] [Indexed: 06/15/2023]
Abstract
The production of recombinant proteins in plant systems is receiving wider attention. Indeed, various plant-produced pharmaceuticals have been shown to be biologically active. However, the production of human growth factors and cytokines in heterologous systems is still challenging because they often act as complex forms, such as homo- or hetero-dimers, and their production is tightly regulated in vivo. In this study, we demonstrated that the mature form of human TGFβ1 produced and purified from Nicotiana benthamiana shows biological activity in animal cells. To produce the mature form of TGFβ1, various recombinant genes containing the mature form of TGFβ1 were generated and produced in N. benthamiana. Of these, a recombinant construct, BiP:M:CBM3:LAP[C33S]:EK:TGFβ1, was expressed at a high level in N. benthamiana. Recombinant proteins were one-step purified using cellulose-binding module 3 (CBM3) as an affinity tag and microcrystalline cellulose (MCC) beads as a matrix. The TGFβ1 recombinant protein bound on MCC beads was proteolytically processed with enterokinase to separate mature TGFβ1. The mature TGFβ1 still associated with Latency Associated Protein, [LAP(C33S)] that had been immobilized on MCC beads was released by HCl treatment. Purified TGFβ1 activated TGFβ1-mediated signaling in the A549 cell line, thereby inducing phosphorylation of SMAD-2, the expression of ZEB-2 and SNAIL1, and the formation of a filopodia-like structure. Based on these results, we propose that active mature TGFβ1, one of the most challenging growth factors to produce in heterologous systems, can be produced from plants at a high degree of purity via a few steps.
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Affiliation(s)
- Aditya Prakash Soni
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
| | - Juhee Lee
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
- Department of Biological Sciences, College of Natural Science, Seoul National University, Seoul, South Korea
| | - Kunyoo Shin
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
- Department of Biological Sciences, College of Natural Science, Seoul National University, Seoul, South Korea
| | - Hisashi Koiwa
- Molecular and Environmental Plant Sciences, Texas A&M University, College Station, TX, United States
- Vegetable and Fruit Development Center, Department of Horticultural Sciences, Texas A&M University, College Station, TX, United States
| | - Inhwan Hwang
- Department of Life Science, Pohang University of Science and Technology, Pohang, South Korea
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7
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Cortijo-Gutiérrez M, Sánchez-Hernández S, Tristán-Manzano M, Maldonado-Pérez N, Lopez-Onieva L, Real PJ, Herrera C, Marchal JA, Martin F, Benabdellah K. Improved Functionality of Integration-Deficient Lentiviral Vectors (IDLVs) by the Inclusion of IS 2 Protein Docks. Pharmaceutics 2021; 13:pharmaceutics13081217. [PMID: 34452178 PMCID: PMC8401568 DOI: 10.3390/pharmaceutics13081217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Revised: 07/30/2021] [Accepted: 08/03/2021] [Indexed: 11/16/2022] Open
Abstract
Integration-deficient lentiviral vectors (IDLVs) have recently generated increasing interest, not only as a tool for transient gene delivery, but also as a technique for detecting off-target cleavage in gene-editing methodologies which rely on customized endonucleases (ENs). Despite their broad potential applications, the efficacy of IDLVs has historically been limited by low transgene expression and by the reduced sensitivity to detect low-frequency off-target events. We have previously reported that the incorporation of the chimeric sequence element IS2 into the long terminal repeat (LTR) of IDLVs increases gene expression levels, while also reducing the episome yield inside transduced cells. Our study demonstrates that the effectiveness of IDLVs relies on the balance between two parameters which can be modulated by the inclusion of IS2 sequences. In the present study, we explore new IDLV configurations harboring several elements based on IS2 modifications engineered to mediate more efficient transgene expression without affecting the targeted cell load. Of all the insulators and configurations analysed, the insertion of the IS2 into the 3′LTR produced the best results. After demonstrating a DAPI-low nuclear gene repositioning of IS2-containing episomes, we determined whether, in addition to a positive effect on transcription, the IS2 could improve the capture of IDLVs on double strand breaks (DSBs). Thus, DSBs were randomly generated, using the etoposide or locus-specific CRISPR-Cas9. Our results show that the IS2 element improved the efficacy of IDLV DSB detection. Altogether, our data indicate that the insertion of IS2 into the LTR of IDLVs improved, not only their transgene expression levels, but also their ability to be inserted into existing DSBs. This could have significant implications for the development of an unbiased detection tool for off-target cleavage sites from different specific nucleases.
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Affiliation(s)
- Marina Cortijo-Gutiérrez
- GENYO, Centre for Genomics and Oncological Research, Genomic Medicine Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (M.C.-G.); (S.S.-H.); (M.T.-M.); (N.M.-P.); (F.M.)
| | - Sabina Sánchez-Hernández
- GENYO, Centre for Genomics and Oncological Research, Genomic Medicine Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (M.C.-G.); (S.S.-H.); (M.T.-M.); (N.M.-P.); (F.M.)
| | - María Tristán-Manzano
- GENYO, Centre for Genomics and Oncological Research, Genomic Medicine Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (M.C.-G.); (S.S.-H.); (M.T.-M.); (N.M.-P.); (F.M.)
| | - Noelia Maldonado-Pérez
- GENYO, Centre for Genomics and Oncological Research, Genomic Medicine Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (M.C.-G.); (S.S.-H.); (M.T.-M.); (N.M.-P.); (F.M.)
| | - Lourdes Lopez-Onieva
- GENYO, Centre for Genomics and Oncological Research, Molecular Oncology Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (L.L.-O.); (P.J.R.)
- Department of Biochemistry and Molecular Biology I, Faculty of Science, University of Granada, Avenida Fuentenueva s/n, 18071 Granada, Spain
| | - Pedro J. Real
- GENYO, Centre for Genomics and Oncological Research, Molecular Oncology Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (L.L.-O.); (P.J.R.)
- Department of Biochemistry and Molecular Biology I, Faculty of Science, University of Granada, Avenida Fuentenueva s/n, 18071 Granada, Spain
- Personalized Oncology Group, Bio-Health Research Institute (ibs Granada), 18016 Granada, Spain
| | - Concha Herrera
- Maimonides Institute of Biomedical Research in Cordoba (IMIBIC), 14004 Cordoba, Spain;
- Department of Haematology, Reina Sofía University Hospital, 14004 Cordoba, Spain
| | - Juan Antonio Marchal
- Biomedical Research Institute (ibs. Granada), 18012 Granada, Spain;
- Biopathology and Regenerative Medicine Institute (IBIMER), Centre for Biomedical Research (CIBM), University of Granada, 18016 Granada, Spain
- Department of Human Anatomy and Embryology, Faculty of Medicine, University of Granada, 18016 Granada, Spain
- Excellence Research Unit: Modeling Nature (MNat), University of Granada, 18016 Granada, Spain
| | - Francisco Martin
- GENYO, Centre for Genomics and Oncological Research, Genomic Medicine Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (M.C.-G.); (S.S.-H.); (M.T.-M.); (N.M.-P.); (F.M.)
| | - Karim Benabdellah
- GENYO, Centre for Genomics and Oncological Research, Genomic Medicine Department, Pfizer-University of Granada-Andalusian Regional Government, Health Sciences Technology Park, Av. de la Illustration 114, 18016 Granada, Spain; (M.C.-G.); (S.S.-H.); (M.T.-M.); (N.M.-P.); (F.M.)
- Correspondence: ; Tel.: +34-958-715-500
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8
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Characterization of the regulatory 5'-flanking region of bovine mucin 2 (MUC2) gene. Mol Cell Biochem 2021; 476:2847-2856. [PMID: 33730299 DOI: 10.1007/s11010-021-04133-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Accepted: 03/06/2021] [Indexed: 10/21/2022]
Abstract
Throughout the intestinal epithelium surface there is an intricate polymer network composed by gel-forming mucins, which plays a protective role due to the formation of a physical, chemical and immunological barrier between the organism and the environment. Mucin 2 (MUC2) is the main mucin in the small and large intestine, and it is expressed specifically in the gastrointestinal tract (GIT), which makes its promoter region an important candidate for expression of heterologous genes of biotechnological interest in the GIT of bovine and other ruminants. In order to characterize the bovine MUC2 promoter we designed primers to amplify and isolate a candidate region for this promoter. The amplified sequence was confirmed by sequencing and cloned into a plasmid vector containing the luciferase (LUC) reporter gene. The regulatory sites of the MUC2 promoter already described in the literature were used to find the putative regulatory sites in the bovine MUC2 promoter region. With these data, some deletions were performed in order to find the promoter sequence with greatest expression capacity and specificity. The constructions were tested by transient transfection assays in LoVo cells (human colorectal adenocarcinoma) and bovine fibroblasts. The quantification of the relative expression of the promoter was measured using dual-luciferase assays. Real-time PCR was performed to analyze the expression of endogenous MUC2. The results presented herein prove that the isolated sequence corresponds to the promoter of bovine MUC2 gene, since it was able to induce expression of a reporter gene in an in vitro cell culture experimental platform.
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9
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Chai YR, Cao XX, Ge MM, Mi CL, Guo X, Wang TY. Knockout of cytidine monophosphate-N-acetylneuraminic acid hydroxylase in Chinese hamster ovary cells by CRISPR/Cas9-based gene-editing technology. Biochem Eng J 2020. [DOI: 10.1016/j.bej.2020.107663] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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10
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Fitzgerald M, Livingston M, Gibbs C, Deans TL. Rosa26 docking sites for investigating genetic circuit silencing in stem cells. Synth Biol (Oxf) 2020; 5:ysaa014. [PMID: 33195816 PMCID: PMC7644442 DOI: 10.1093/synbio/ysaa014] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2020] [Revised: 08/01/2020] [Accepted: 08/04/2020] [Indexed: 12/31/2022] Open
Abstract
Approaches in mammalian synthetic biology have transformed how cells can be programmed to have reliable and predictable behavior, however, the majority of mammalian synthetic biology has been accomplished using immortalized cell lines that are easy to grow and easy to transfect. Genetic circuits that integrate into the genome of these immortalized cell lines remain functional for many generations, often for the lifetime of the cells, yet when genetic circuits are integrated into the genome of stem cells gene silencing is observed within a few generations. To investigate the reactivation of silenced genetic circuits in stem cells, the Rosa26 locus of mouse pluripotent stem cells was modified to contain docking sites for site-specific integration of genetic circuits. We show that the silencing of genetic circuits can be reversed with the addition of sodium butyrate, a histone deacetylase inhibitor. These findings demonstrate an approach to reactivate the function of genetic circuits in pluripotent stem cells to ensure robust function over many generations. Altogether, this work introduces an approach to overcome the silencing of genetic circuits in pluripotent stem cells that may enable the use of genetic circuits in pluripotent stem cells for long-term function.
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Affiliation(s)
- Michael Fitzgerald
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Mark Livingston
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Chelsea Gibbs
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
| | - Tara L Deans
- Department of Biomedical Engineering, University of Utah, Salt Lake City, UT 84112, USA
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11
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Guo X, Wang C, Wang TY. Chromatin-modifying elements for recombinant protein production in mammalian cell systems. Crit Rev Biotechnol 2020; 40:1035-1043. [PMID: 32777953 DOI: 10.1080/07388551.2020.1805401] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Mammalian cells are the preferred choice system for the production of complex molecules, such as recombinant therapeutic proteins. Although the technology for increasing the yield of proteins has improved rapidly, the process of selecting, identifying as well as maintaining high-yield cell clones is still troublesome, time-consuming and usually uncertain. Optimization of expression vectors is one of the most effective methods for enhancing protein expression levels. Several commonly used chromatin-modifying elements, including the matrix attachment region, ubiquitous chromatin opening elements, insulators, stabilizing anti-repressor elements can be used to increase the expression level and stability of recombinant proteins. In this review, these chromatin-modifying elements used for the expression vector optimization in mammalian cells are summarized, and future strategies for the utilization of expression cassettes are also discussed.
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Affiliation(s)
- Xiao Guo
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China.,Perildicals Publishing House, Xinxiang Medical University, Xinxiang, China
| | - Chong Wang
- School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China.,Perildicals Publishing House, Xinxiang Medical University, Xinxiang, China
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12
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Fusion with matrix attachment regions enhances expression of recombinant protein in human HT-1080 cells. J Biosci Bioeng 2020; 130:533-538. [PMID: 32773266 DOI: 10.1016/j.jbiosc.2020.07.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 07/09/2020] [Accepted: 07/09/2020] [Indexed: 11/23/2022]
Abstract
Like endogenous proteins, recombinant foreign proteins produced in human cell lines also need post-translational modifications. However, high and long-term expression of a gene of interest (GOI) presents significant challenges for recombinant protein production in human cells. In this work, the effect of human matrix attachment region elements (MARs), including the β-globin MAR (gMAR), chicken lysozyme MAR (cMAR), and a combination of these two, on the stable expression of GOI was assessed in human HT-1080 cells. After transfection with vectors containing the MAR elements and eGFP, stably HT-1080 cell pools were obtained under selective pressure. eGFP protein expression was analyzed by flow cytometry, while transgene copy number and eGFP mRNA expression levels were determined with qPCR and qRT-PCR technology. We found that MARs could not enhance transfection efficiency, but gMAR could significantly increase eGFP expression in stable HT-1080 cell pools by approximately 2.69-fold. Moreover, gMAR could also increase eGFP expression stability during long-term culture. Lastly, we showed that the effect of the MARs on transgenes was related to the gene copy number. In summary, this study found that MARs could both enhance the transgene expression and stability in HT-1080 cells.
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13
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piggyBac-Based Non-Viral In Vivo Gene Delivery Useful for Production of Genetically Modified Animals and Organs. Pharmaceutics 2020; 12:pharmaceutics12030277. [PMID: 32204422 PMCID: PMC7151002 DOI: 10.3390/pharmaceutics12030277] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 03/17/2020] [Accepted: 03/18/2020] [Indexed: 11/17/2022] Open
Abstract
In vivo gene delivery involves direct injection of nucleic acids (NAs) into tissues, organs, or tail-veins. It has been recognized as a useful tool for evaluating the function of a gene of interest (GOI), creating models for human disease and basic research targeting gene therapy. Cargo frequently used for gene delivery are largely divided into viral and non-viral vectors. Viral vectors have strong infectious activity and do not require the use of instruments or reagents helpful for gene delivery but bear immunological and tumorigenic problems. In contrast, non-viral vectors strictly require instruments (i.e., electroporator) or reagents (i.e., liposomes) for enhanced uptake of NAs by cells and are often accompanied by weak transfection activity, with less immunological and tumorigenic problems. Chromosomal integration of GOI-bearing transgenes would be ideal for achieving long-term expression of GOI. piggyBac (PB), one of three transposons (PB, Sleeping Beauty (SB), and Tol2) found thus far, has been used for efficient transfection of GOI in various mammalian cells in vitro and in vivo. In this review, we outline recent achievements of PB-based production of genetically modified animals and organs and will provide some experimental concepts using this system.
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14
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Schweickert PG, Cheng Z. Application of Genetic Engineering in Biotherapeutics Development. J Pharm Innov 2019. [DOI: 10.1007/s12247-019-09411-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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15
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Narwade N, Patel S, Alam A, Chattopadhyay S, Mittal S, Kulkarni A. Mapping of scaffold/matrix attachment regions in human genome: a data mining exercise. Nucleic Acids Res 2019; 47:7247-7261. [PMID: 31265077 PMCID: PMC6698742 DOI: 10.1093/nar/gkz562] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2019] [Revised: 06/08/2019] [Accepted: 06/27/2019] [Indexed: 11/14/2022] Open
Abstract
Scaffold/matrix attachment regions (S/MARs) are DNA elements that serve to compartmentalize the chromatin into structural and functional domains. These elements are involved in control of gene expression which governs the phenotype and also plays role in disease biology. Therefore, genome-wide understanding of these elements holds great therapeutic promise. Several attempts have been made toward identification of S/MARs in genomes of various organisms including human. However, a comprehensive genome-wide map of human S/MARs is yet not available. Toward this objective, ChIP-Seq data of 14 S/MAR binding proteins were analyzed and the binding site coordinates of these proteins were used to prepare a non-redundant S/MAR dataset of human genome. Along with co-ordinate (location) details of S/MARs, the dataset also revealed details of S/MAR features, namely, length, inter-SMAR length (the chromatin loop size), nucleotide repeats, motif abundance, chromosomal distribution and genomic context. S/MARs identified in present study and their subsequent analysis also suggests that these elements act as hotspots for integration of retroviruses. Therefore, these data will help toward better understanding of genome functioning and designing effective anti-viral therapeutics. In order to facilitate user friendly browsing and retrieval of the data obtained in present study, a web interface, MARome (http://bioinfo.net.in/MARome), has been developed.
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Affiliation(s)
- Nitin Narwade
- Bioinformatics Centre, Savitribai Phule Pune University, Pune - 411 007, Maharashtra, India
| | - Sonal Patel
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Pune - 411 007, Maharashtra, India
| | - Aftab Alam
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Pune - 411 007, Maharashtra, India
| | - Samit Chattopadhyay
- Chromatin and Disease Biology Lab, National Centre for Cell Science, Pune - 411 007, Maharashtra, India.,Indian Institute of Chemical Biology, 4, Raja S.C. Mullick Road, Jadavpur, Kolkata - 700 032, West Bengal, India
| | - Smriti Mittal
- Department of Biotechnology, Savitribai Phule Pune University, Pune - 411 007, Maharashtra, India
| | - Abhijeet Kulkarni
- Bioinformatics Centre, Savitribai Phule Pune University, Pune - 411 007, Maharashtra, India
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16
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Gupta K, Parasnis M, Jain R, Dandekar P. Vector-related stratagems for enhanced monoclonal antibody production in mammalian cells. Biotechnol Adv 2019; 37:107415. [DOI: 10.1016/j.biotechadv.2019.107415] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2018] [Revised: 07/01/2019] [Accepted: 07/01/2019] [Indexed: 12/16/2022]
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17
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Zhang JH, Zhang JH, Wang XY, Xu DH, Wang TY. Distance effect characteristic of the matrix attachment region increases recombinant protein expression in Chinese hamster ovary cells. Biotechnol Lett 2019; 42:187-196. [PMID: 31776751 DOI: 10.1007/s10529-019-02775-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2019] [Accepted: 11/24/2019] [Indexed: 12/21/2022]
Abstract
OBJECTIVES Previously, we have found that the matrix attachment region (MAR) may confer a 'distance effect' on transgene expression. This work aims to systematically explore the increased transgene expression in transfected Chinese hamster ovary (CHO) cells due to the characteristics of MAR and its mechanism. RESULTS Compared with the control vector, 500 and 1000 bp DNA distances between MAR and the cytomegalovirus promoter can increase transgene expression by 1.77- and 1.56-fold, respectively. Meanwhile, transgene expression was not affected when 2000 and 2500 bp spacer DNAs were inserted, but a declining trend was observed when a 1500 bp spacer DNA was inserted. The vector containing a 500 bp DNA distance significantly increased the expression of the enhanced green fluorescent protein, and this increase was not related to transgene copy numbers. CONCLUSIONS A short DNA distance-containing MAR confers high transgene expression level in transfected CHO cells, but a distance threshold does not exist in the vector system.
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Affiliation(s)
- Jun-He Zhang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003, Henan, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Ji-Hong Zhang
- Department of Histology and Embryology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao-Yin Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003, Henan, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Dan-Hua Xu
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003, Henan, China.,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003, Henan, China. .,International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China.
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18
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Li YM, Wang M, Wang TY, Wei YG, Guo X, Mi CL, Zhao CP, Cao XX, Dou YY. Effects of different 2A peptides on transgene expression mediated by tricistronic vectors in transfected CHO cells. Mol Biol Rep 2019; 47:469-475. [PMID: 31659692 DOI: 10.1007/s11033-019-05153-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2019] [Accepted: 10/22/2019] [Indexed: 12/22/2022]
Abstract
Multicistronic vectors can increase transgene expression and decrease the imbalance of gene expression in the Chinese hamster ovary (CHO) cell expression system. Small, self-cleaving 2A peptides have a high cleavage efficiency and are essential for constructing high-expression multicistronic vectors. In this study, we investigated the effects of two different 2A peptides on transgene expression in CHO cells via their mediating action on tricistronic vectors. The enhanced green fluorescent protein (eGFP) and red fluorescent protein (RFP) genes were linked by the porcine teschovirus-1 (P2A) and Thosea asigna virus (T2A) peptides in a multicistronic vector. We transfected CHO cells with these vectors and screened for the presence of blasticidin-resistant colonies. Flow cytometry and real-time quantitative PCR (qPCR) were used to detect the expression levels of eGFP and RFP and the copy numbers of stably transfected cells. The results showed that P2A could enhance eGFP and RFP expression by 1.48- and 1.47-fold, respectively, compared to T2A. The expression levels of the genes were not proportional to their copy numbers. In conclusion, we found that P2A can effectively drive transgene expression in CHO cells and a potent 2A peptide can be used for recombinant protein production in the CHO cell system.
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Affiliation(s)
- Yan-Mei Li
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
| | - Meng Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China. .,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.
| | - Yong-Ge Wei
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
| | - Xiao Guo
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
| | - Chun-Liu Mi
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
| | - Chun-Peng Zhao
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
| | - Xiang-Xiang Cao
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
| | - Yuan-Yuan Dou
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Jinsui Road, Xinxiang, 453003, Henan, People's Republic of China
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19
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Jia YL, Guo X, Ni TJ, Lu JT, Wang XY, Wang TY. Novel short synthetic matrix attachment region for enhancing transgenic expression in recombinant Chinese hamster ovary cells. J Cell Biochem 2019; 120:18478-18486. [PMID: 31168866 DOI: 10.1002/jcb.29165] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2019] [Revised: 05/18/2019] [Accepted: 05/23/2019] [Indexed: 01/17/2023]
Abstract
Matrix attachment regions (MARs) are DNA fragments with specific motifs that enhance transgenic expression; however, the characteristics and functions of these elements remain unclear. In this study, we designed and synthesized three short chimeric MARs, namely, SM4, SM5, and SM6, with different numbers and orders of motifs on the basis of the features and motifs of previously reported MARs, namely, SM1, SM2, and SM3, respectively. Expression vectors with six synthetic MARs flanking the down or upstream of the expression cassette for enhanced green fluorescence protein (EGFP) were constructed and introduced into Chinese hamster ovary (CHO) cells. Results indicated that the EGFP expression of the CHO cells with transfection bySM4, SM5, or SM6-containing vectors was higher than that of those containing SM1, SM2, or SM3 regardless of the MAR insertion position. The improving effect of SM5 was particularly pronounced. Transgenic expression was further enhanced with the increasing SM5 copy number. Bioinformatics analysis indicated that several arrangements of the DNA-binding motifs for CEBP, FAST, Hox, glutathione, and NMP4 may help increase transgenic expression levels and the average population of highly expressed cells. Our findings on novel synthetic MARs will help establish stable expression systems in mammalian cells.
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Affiliation(s)
- Yan-Long Jia
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao Guo
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Jun Ni
- School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan, China
| | - Jiang-Tao Lu
- School of Pharmacy, Xinxiang Medical University, Xinxiang, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao-Yin Wang
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China.,School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China.,School of Basic Medicine, Xinxiang Medical University, Xinxiang, Henan, China
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20
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Gao JH, Wang TY, Zhang MY, Shi F, Gu SZ. Identification of consensus sequence from matrix attachment regions and functional analysis of its activity in stably transfected Chinese hamster ovary cells. J Cell Biochem 2019; 120:13985-13993. [PMID: 30957285 DOI: 10.1002/jcb.28673] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Revised: 12/30/2018] [Accepted: 01/09/2019] [Indexed: 01/01/2023]
Abstract
Matrix attachment regions (MARs) can enhance transgene expression levels and maintain stability. However, the consensus sequence from MARs and its functional analysis remains to be examined. Here, we assessed a possible consensus sequence from MARs and assessed its activity in stably transfected Chinese hamster ovary (CHO) cells. First, we analyzed the effects of 10 MARs on transfected CHO cells and then analyzed the consensus motifs from these MARs using a bioinformatics method. The consensus sequence was synthesized and cloned upstream or downstream of the eukaryotic vector. The constructs were transfected into CHO cells and the expression levels and stability of enhanced green fluorescent protein were detected by flow cytometry. The results indicated that eight of the ten MARs increased transgene expression in transfected CHO cells. Three consensus motifs were found after bioinformatics analyses. The consensus sequence tandemly enhanced transgene expression when it was inserted into the eukaryotic expression vector; the effect of the addition upstream was stronger than that downstream. Thus, we found a MAR consensus sequence that may regulate the MAR-mediated increase in transgene expression.
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Affiliation(s)
- Jian-Hui Gao
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Mao-Ying Zhang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Fang Shi
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Shan-Zhi Gu
- College of Forensic Medicine, Xi'an Jiaotong University Health Science Center, Xi'an, Shaanxi, China
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21
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Jia YL, Guo X, Wang XC, Wang TY. Human genome-derived TOP1 matrix attachment region enhances transgene expression in the transfected CHO cells. Biotechnol Lett 2019; 41:701-709. [DOI: 10.1007/s10529-019-02673-7] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 04/02/2019] [Indexed: 01/08/2023]
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22
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Sánchez-Hernández S, Gutierrez-Guerrero A, Martín-Guerra R, Cortijo-Gutierrez M, Tristán-Manzano M, Rodriguez-Perales S, Sanchez L, Garcia-Perez JL, Chato-Astrain J, Fernandez-Valades R, Carrillo-Galvez AB, Anderson P, Montes R, Real PJ, Martin F, Benabdellah K. The IS2 Element Improves Transcription Efficiency of Integration-Deficient Lentiviral Vector Episomes. MOLECULAR THERAPY-NUCLEIC ACIDS 2018; 13:16-28. [PMID: 30227274 PMCID: PMC6141704 DOI: 10.1016/j.omtn.2018.08.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Revised: 07/02/2018] [Accepted: 08/14/2018] [Indexed: 02/06/2023]
Abstract
Integration-defective lentiviral vectors (IDLVs) have become an important alternative tool for gene therapy applications and basic research. Unfortunately, IDLVs show lower transgene expression as compared to their integrating counterparts. In this study, we aimed to improve the expression levels of IDLVs by inserting the IS2 element, which harbors SARs and HS4 sequences, into their LTRs (SE-IS2-IDLVs). Contrary to our expectations, the presence of the IS2 element did not abrogate epigenetic silencing by histone deacetylases. In addition, the IS2 element reduced episome levels in IDLV-transduced cells. Interestingly, despite these negative effects, SE-IS2-IDLVs outperformed SE-IDLVs in terms of percentage and expression levels of the transgene in several cell lines, including neurons, neuronal progenitor cells, and induced pluripotent stem cells. We estimated that the IS2 element enhances the transcriptional activity of IDLV LTR circles 6- to 7-fold. The final effect the IS2 element in IDLVs will greatly depend on the target cell and the balance between the negative versus the positive effects of the IS2 element in each cell type. The better performance of SE-IS2-IDLVs was not due to improved stability or differences in the proportions of 1-LTR versus 2-LTR circles but probably to a re-positioning of IS2-episomes into transcriptionally active regions.
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Affiliation(s)
- Sabina Sánchez-Hernández
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Alejandra Gutierrez-Guerrero
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Rocío Martín-Guerra
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Marina Cortijo-Gutierrez
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - María Tristán-Manzano
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Sandra Rodriguez-Perales
- Molecular Cytogenetics and Genome Editing Unit, Human Cancer Genetics Department, CNIO, Melchor Fernandez Almagro 3, 28029 Madrid, Spain
| | - Laura Sanchez
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Jose Luis Garcia-Perez
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Jesus Chato-Astrain
- Department of Histology, Tissue Engineering Group, University of Granada, Granada, Spain
| | - Ricardo Fernandez-Valades
- Pediatric Surgery Department, University Hospital "Virgen de las Nieves," Avda. Fuerzas Armadas 2, 18014 Granada, Spain
| | - Ana Belén Carrillo-Galvez
- Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Per Anderson
- LentiStem Biotech, GENYO, Avda. de la Ilustración 114, 18016 PTS Granada, Spain; Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Rosa Montes
- Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain
| | - Pedro J Real
- Oncology Department, GENYO, Centre for Genomics and Oncology, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; Departament of Biochemistry and Molecular Biology I, University of Granada, Granada, Spain
| | - Francisco Martin
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; LentiStem Biotech, GENYO, Avda. de la Ilustración 114, 18016 PTS Granada, Spain.
| | - Karim Benabdellah
- Genomic Medicine Department, GENYO, Centre for Genomics and Oncological Research, Pfizer-University of Granada-Andalusian Regional Government, PTS Granada, 18016 Granada, Spain; LentiStem Biotech, GENYO, Avda. de la Ilustración 114, 18016 PTS Granada, Spain.
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23
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Li Q, Zhao CP, Lin Y, Song C, Wang F, Wang TY. Two human MARs effectively increase transgene expression in transfected CHO cells. J Cell Mol Med 2018; 23:1613-1616. [PMID: 30450759 PMCID: PMC6349195 DOI: 10.1111/jcmm.14018] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/15/2018] [Accepted: 10/16/2018] [Indexed: 12/12/2022] Open
Abstract
Matrix attachment regions (MARs) can enhance the expression level of transgene in Chinese hamster ovaries (CHO) cell expression system. However, improvements in function and analyses of the mechanism remains unclear. In this study, we screened two new and more functional MAR elements from the human genome DNA. The human MAR-3 and MAR-7 element were cloned and inserted downstream of the polyA site in a eukaryotic vector. The constructs were transfected into CHO cells, and screened under G418 to produce the stably transfected cell pools. The expression levels and stability of enhanced green fluorescent protein (eGFP) were detected by flow cytometry. The transgene copy number and transgene expression at mRNA level were detected by quantitative real-time PCR. The results showed that the expression level of eGFP of cells transfected with MAR-containing vectors were all higher than those of the vectors without MARs under transient and stably transfection. The enhancing effect of MAR-7 was higher than that of MAR-3. Additionally, we found that MAR significantly increased eGFP copy numbers and eGFP gene mRNA expression level as compared with the vector without. In conclusion, MAR-3 and MAR-7 gene can promote the expression of transgene in transfected CHO cells, and its effect may be related to the increase of the number of copies.
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Affiliation(s)
- Qin Li
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Chun-Peng Zhao
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Yan Lin
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Chao Song
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Fang Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Henan, China.,International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of Henan, Xinxiang Medical University, Xinxiang, Henan, China
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24
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Mannully S, L.N. R, Pulicherla K. Perspectives on progressive strategies and recent trends in the production of recombinant human factor VIII. Int J Biol Macromol 2018; 119:496-504. [DOI: 10.1016/j.ijbiomac.2018.07.164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/11/2018] [Accepted: 07/26/2018] [Indexed: 10/28/2022]
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25
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Hamaker NK, Lee KH. Site-specific Integration Ushers in a New Era of Precise CHO Cell Line Engineering. Curr Opin Chem Eng 2018; 22:152-160. [PMID: 31086757 DOI: 10.1016/j.coche.2018.09.011] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Chinese hamster ovary (CHO) cells are widely used for the production of therapeutic proteins. Customarily, CHO production cell lines are established through random integration, which requires laborious screening of many clones to isolate suitable producers. In contrast, site-specific integration (SSI) accelerates cell line development by targeting integration of transgenes to pre-validated genomic loci capable of supporting high and stable expression. To date, a relatively small number of these so called 'hot spots' have been identified, mainly through empirical methods. Nevertheless, nuclease-mediated and recombinase-mediated SSI have revolutionized cell line engineering by enabling rational and reproducible transgene targeting.
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Affiliation(s)
- Nathaniel K Hamaker
- Delaware Biotechnology Institute, Newark, DE.,Chemical and Biomolecular Engineering, University of Delaware, Newark, DE
| | - Kelvin H Lee
- Delaware Biotechnology Institute, Newark, DE.,Chemical and Biomolecular Engineering, University of Delaware, Newark, DE
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26
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Wang W, Guo X, Li YM, Wang XY, Yang XJ, Wang YF, Wang TY. Enhanced transgene expression using cis-acting elements combined with the EF1 promoter in a mammalian expression system. Eur J Pharm Sci 2018; 123:539-545. [DOI: 10.1016/j.ejps.2018.08.016] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Revised: 07/12/2018] [Accepted: 08/11/2018] [Indexed: 10/28/2022]
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27
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Jia Y, Guo X, Lu J, Wang X, Qiu L, Wang T. CRISPR/Cas9-mediated gene knockout for DNA methyltransferase Dnmt3a in CHO cells displays enhanced transgenic expression and long-term stability. J Cell Mol Med 2018; 22:4106-4116. [PMID: 29851281 PMCID: PMC6111867 DOI: 10.1111/jcmm.13687] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Accepted: 04/23/2018] [Indexed: 12/14/2022] Open
Abstract
CHO cells are the preferred host for the production of complex pharmaceutical proteins in the biopharmaceutical industry, and genome engineering of CHO cells would benefit product yield and stability. Here, we demonstrated the efficacy of a Dnmt3a-deficient CHO cell line created by CRISPR/Cas9 genome editing technology through gene disruptions in Dnmt3a, which encode the proteins involved in DNA methyltransferases. The transgenes, which were driven by the 2 commonly used CMV and EF1α promoters, were evaluated for their expression level and stability. The methylation levels of CpG sites in the promoter regions and the global DNA were compared in the transfected cells. The Dnmt3a-deficent CHO cell line based on Dnmt3a KO displayed an enhanced long-term stability of transgene expression under the control of the CMV promoter in transfected cells in over 60 passages. Under the CMV promoter, the Dnmt3a-deficent cell line with a high transgene expression displayed a low methylation rate in the promoter region and global DNA. Under the EF1α promoter, the Dnmt3a-deficient and normal cell lines with low transgene expression exhibited high DNA methylation rates. These findings provide insight into cell line modification and design for improved recombinant protein production in CHO and other mammalian cells.
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Affiliation(s)
- Yan‐Long Jia
- College of PharmacyXinxiang Medical UniversityXinxiangHenanChina
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of HenanXinxiang Medical UniversityXinxiangHenanChina
| | - Xiao Guo
- College of PharmacyXinxiang Medical UniversityXinxiangHenanChina
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of HenanXinxiang Medical UniversityXinxiangHenanChina
| | - Jiang‐Tao Lu
- College of PharmacyXinxiang Medical UniversityXinxiangHenanChina
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of HenanXinxiang Medical UniversityXinxiangHenanChina
| | - Xiao‐Yin Wang
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of HenanXinxiang Medical UniversityXinxiangHenanChina
- School of Basic MedicineXinxiang Medical UniversityXinxiangHenanChina
| | - Le‐Le Qiu
- School of Basic MedicineXinxiang Medical UniversityXinxiangHenanChina
| | - Tian‐Yun Wang
- International Joint Research Laboratory for Recombiant Pharmaceutical Protein Expression System of HenanXinxiang Medical UniversityXinxiangHenanChina
- School of Basic MedicineXinxiang Medical UniversityXinxiangHenanChina
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28
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Xu DH, Wang XY, Jia YL, Wang TY, Tian ZW, Feng X, Zhang YN. SV40 intron, a potent strong intron element that effectively increases transgene expression in transfected Chinese hamster ovary cells. J Cell Mol Med 2018; 22:2231-2239. [PMID: 29441681 PMCID: PMC5867124 DOI: 10.1111/jcmm.13504] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 11/15/2017] [Indexed: 12/20/2022] Open
Abstract
Chinese hamster ovary (CHO) cells have become the most widely utilized mammalian cell line for the production of recombinant proteins. However, the product yield and transgene instability need to be further increased and solved. In this study, we investigated the effect of five different introns on transgene expression in CHO cells. hCMV intron A, adenovirus tripartite leader sequence intron, SV40 intron, Chinese hamster EF-1alpha gene intron 1 and intervening sequence intron were cloned downstream of the eGFP expression cassette in a eukaryotic vector, which was then transfected into CHO cells. qRT-PCR and flow cytometry were used to explore eGFP expression levels. And gene copy number was also detected by qPCR, respectively. Furthermore, the erythropoietin (EPO) protein was used to test the selected more strong intron. The results showed that SV40 intron exhibited the highest transgene expression level among the five compared intron elements under transient and stable transfections. In addition, the SV40 intron element can increase the ratio of positive colonies and decrease the coefficient of variation in transgene expression level. Moreover, the transgene expression level was not related to the gene copy number in stable transfected CHO cells. Also, the SV40 intron induced higher level of EPO expression than IVS intron in transfected CHO cell. In conclusion, SV40 intron is a potent strong intron element that increases transgene expression, which can readily be used to more efficient transgenic protein production in CHO cells.
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Affiliation(s)
- Dan-Hua Xu
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao-Yin Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Yan-Long Jia
- Pharmacy collage, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Zheng-Wei Tian
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xin Feng
- Grade 2014, The Third Clinical Medical College of Xinxiang Medical University, Xinxiang, Henan, China
| | - Yin-Na Zhang
- Grade 2014, The Third Clinical Medical College of Xinxiang Medical University, Xinxiang, Henan, China
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29
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Romanova N, Noll T. Engineered and Natural Promoters and Chromatin-Modifying Elements for Recombinant Protein Expression in CHO Cells. Biotechnol J 2017; 13:e1700232. [DOI: 10.1002/biot.201700232] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Revised: 11/07/2017] [Indexed: 12/13/2022]
Affiliation(s)
- Nadiya Romanova
- Cell Culture Technology; Faculty of Technology; Bielefeld University; Germany
| | - Thomas Noll
- Cell Culture Technology; Faculty of Technology; Bielefeld University; Germany
- Bielefeld University; Center for Biotechnology (CeBiTec); Germany
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30
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Tian ZW, Xu DH, Wang TY, Wang XY, Xu HY, Zhao CP, Xu GH. Identification of a potent MAR element from the human genome and assessment of its activity in stably transfected CHO cells. J Cell Mol Med 2017; 22:1095-1102. [PMID: 29077269 PMCID: PMC5783848 DOI: 10.1111/jcmm.13361] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2017] [Accepted: 07/25/2017] [Indexed: 01/23/2023] Open
Abstract
Low-level and unstable transgene expression are common issues using the CHO cell expression system. Matrix attachment regions (MARs) enhance transgene expression levels, but additional research is needed to improve their function and to determine their mechanism of action. MAR-6 from CHO chromosomes actively mediates high and consistent gene expression. In this study, we compared the effects of two new MARs and MAR-6 on transgene expression in recombinant CHO cells and found one potent MAR element that can significantly increase transgene expression. Two MARs, including the human CSP-B MAR element and DHFR intron MAR element from CHO cells, were cloned and inserted downstream of the poly(A) site in a eukaryotic vector. The constructs were transfected into CHO cells, and the expression levels and stability of eGFP were detected by flow cytometry. The three MAR sequences can be ranked in terms of overall eGFP expression, in decreasing order, as follows: human CSP-B, DHFR intron MAR element and MAR-6. Additionally, as expected, the three MAR-containing vectors showed higher transfection efficiencies and transient transgene expression in comparison with those of the non-MAR-containing vector. Bioinformatics analysis indicated that the NFAT and VIBP elements within MAR sequences may contribute to the enhancement of eGFP expression. In conclusion, the human CSP-B MAR element can improve transgene expression and its effects may be related to the NFAT and VIBP elements.
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Affiliation(s)
- Zheng-Wei Tian
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Dan-Hua Xu
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Xiao-Yin Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Hong-Yan Xu
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Chun-Peng Zhao
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
| | - Guang-Hua Xu
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, Henan, China
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31
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Li Q, Wang W, Guo X, Jia YL, Wang YF, Wang TY. A short synthetic chimeric sequence harboring matrix attachment region/PSAR2 increases transgene expression in Chinese hamster ovary cells. Biosci Biotechnol Biochem 2017; 81:1755-1761. [DOI: 10.1080/09168451.2017.1350563] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
Abstract
A chimeric DNA fragment containing an interferon-beta matrix attachment region (MAR) and an immunoglobulin MAR (PSAR2) was synthesized. PSAR2 was cloned into the upstream or downstream region of an enhanced green fluorescent protein (eGFP) expression cassette in a eukaryotic vector, which was then transfected into CHO cells. The results showed that PSAR2 did not effectively increase transgene expression when it was cloned into the upstream region of the eGFP expression cassette. However, when inserted downstream of the eGFP expression cassette, PSAR2-enhanced transient transgene expression and significantly increased the numbers of stably transfected cells compared with the control vector. Additionally, PSAR2 significantly increased eGFP copy numbers as compared with the control vector. PSAR2 could significantly enhance transgene expression in CHO cells according to the position in the vector and increased transgene copy numbers. We found a short chimeric sequence harboring two MARs effectively increased transgene expression in CHO cells.
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Affiliation(s)
- Qin Li
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China
| | - Wen Wang
- Pharmacy College, Xinxiang Medical University, Xinxiang, China
| | - Xiao Guo
- Pharmacy College, Xinxiang Medical University, Xinxiang, China
| | - Yan-Long Jia
- Pharmacy College, Xinxiang Medical University, Xinxiang, China
| | - Yan-Fang Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China
| | - Tian-Yun Wang
- Department of Biochemistry and Molecular Biology, Xinxiang Medical University, Xinxiang, China
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