1
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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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2
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Zhang J, Zhang J, Cheng S, Yang W, Li S. Enhanced transgene expression using two β-globin MARs flanking expression cassettes in stably transfected CHO-K1 cells. 3 Biotech 2019; 9:435. [PMID: 31696040 DOI: 10.1007/s13205-019-1971-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/23/2019] [Indexed: 02/02/2023] Open
Abstract
In this study, we systemically investigated the positions and orientations of matrix attachment regions (MARs) in expression vectors to fully explore the mechanism for improving transgene expression. We constructed 14 vectors that incorporated human β-globin MARs into pIRES-eGFP backbone vectors. The MARs flanked the eGFP expression cassette or promoter in a forward/reverse orientation. After stable transfection into CHO-K1 cells with these vectors, eGFP expression levels were increased significantly relative to that of the control vector (MAR-devoid) when two MARs flanking the expression cassette were incorporated, followed by those at the 5' site (upstream of the promoter). Simultaneously, the percentage of the eGFP-expressing cells was elevated to some extent. The vector with both MARs in forward orientation flanking the expression cassette yielded the highest transgene expression levels (2.5-fold). The orientation (forward or reverse) of the MARs did not present a significant difference when added in the same site. In addition, transgene expression levels were not exclusively dependent on transgene copy numbers. Bioinformatic analysis indicated that some specific transcription factors may contribute to the transcriptional process. In conclusion, two MARs in a forward orientation and flanking the expression cassette comprised the optimal construct for improving the stable transgene expression in the CHO-K1 cells. The effects may be related to specific transcription factors, such as PRDM1 and REL.
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Affiliation(s)
- Jihong Zhang
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Junhe Zhang
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Shan Cheng
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
| | - Wenwen Yang
- 1School of Basic Medical Sciences, Xinxiang Medical University, No. 601 Jinsui Road, Xinxiang, 453003 Henan China
- International Joint Research Laboratory for Recombinant Pharmaceutical Protein Expression System of Henan, Xinxiang, 453003 China
| | - Shijiang Li
- 3The First Affiliated Hospital of Xinxiang Medical University, Weihui, 453100 China
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3
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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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4
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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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5
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Stiewe T, Haran TE. How mutations shape p53 interactions with the genome to promote tumorigenesis and drug resistance. Drug Resist Updat 2018; 38:27-43. [PMID: 29857816 DOI: 10.1016/j.drup.2018.05.001] [Citation(s) in RCA: 76] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/27/2018] [Accepted: 05/03/2018] [Indexed: 12/31/2022]
Abstract
The tumor suppressive transcription factor p53 regulates a wide array of cellular processes that confer upon cells an essential protection against cancer development. Wild-type p53 regulates gene expression by directly binding to DNA in a sequence-specific manner. p53 missense mutations are the most common mutations in malignant cells and can be regarded as synonymous with anticancer drug resistance and poor prognosis. The current review provides an overview of how the extraordinary variety of more than 2000 different mutant p53 proteins, known as the p53 mutome, affect the interaction of p53 with DNA. We discuss how the classification of p53 mutations to loss of function (LOF), gain of function (GOF), and dominant-negative (DN) inhibition of a remaining wild-type allele, hides a complex p53 mutation spectrum that depends on the distinctive nature of each mutant protein, requiring different therapeutic strategies for each mutant p53 protein. We propose to regard the different mutant p53 categories as continuous variables, that may not be independent of each other. In particular, we suggest here to consider GOF mutations as a special subset of LOF mutations, especially when mutant p53 binds to DNA through cooperation with other transcription factors, and we present a model for GOF mechanism that consolidates many observations on the GOF phenomenon. We review how novel mutant p53 targeting approaches aim to restore a wild-type-like DNA interaction and to overcome resistance to cancer therapy.
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Affiliation(s)
- Thorsten Stiewe
- Institute of Molecular Oncology, Philipps-University, 35037 Marburg, Germany.
| | - Tali E Haran
- Department of Biology, Technion-Israel Institute of Technology, Technion City, Haifa 32000, Israel.
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6
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Lalonde ME, Durocher Y. Therapeutic glycoprotein production in mammalian cells. J Biotechnol 2017; 251:128-140. [DOI: 10.1016/j.jbiotec.2017.04.028] [Citation(s) in RCA: 165] [Impact Index Per Article: 23.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2016] [Revised: 04/12/2017] [Accepted: 04/23/2017] [Indexed: 12/12/2022]
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7
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Kostyrko K, Neuenschwander S, Junier T, Regamey A, Iseli C, Schmid-Siegert E, Bosshard S, Majocchi S, Le Fourn V, Girod PA, Xenarios I, Mermod N. MAR-Mediated transgene integration into permissive chromatin and increased expression by recombination pathway engineering. Biotechnol Bioeng 2016; 114:384-396. [PMID: 27575535 PMCID: PMC5215416 DOI: 10.1002/bit.26086] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2016] [Revised: 08/03/2016] [Accepted: 08/25/2016] [Indexed: 12/27/2022]
Abstract
Untargeted plasmid integration into mammalian cell genomes remains a poorly understood and inefficient process. The formation of plasmid concatemers and their genomic integration has been ascribed either to non-homologous end-joining (NHEJ) or homologous recombination (HR) DNA repair pathways. However, a direct involvement of these pathways has remained unclear. Here, we show that the silencing of many HR factors enhanced plasmid concatemer formation and stable expression of the gene of interest in Chinese hamster ovary (CHO) cells, while the inhibition of NHEJ had no effect. However, genomic integration was decreased by the silencing of specific HR components, such as Rad51, and DNA synthesis-dependent microhomology-mediated end-joining (SD-MMEJ) activities. Genome-wide analysis of the integration loci and junction sequences validated the prevalent use of the SD-MMEJ pathway for transgene integration close to cellular genes, an effect shared with matrix attachment region (MAR) DNA elements that stimulate plasmid integration and expression. Overall, we conclude that SD-MMEJ is the main mechanism driving the illegitimate genomic integration of foreign DNA in CHO cells, and we provide a recombination engineering approach that increases transgene integration and recombinant protein expression in these cells. Biotechnol. Bioeng. 2017;114: 384-396. © 2016 The Authors. Biotechnology and Bioengineering published by Wiley Periodicals, Inc.
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Affiliation(s)
- Kaja Kostyrko
- Department of Fundamental Microbiology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | | | - Thomas Junier
- Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | | | | | - Sandra Bosshard
- Department of Fundamental Microbiology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | - Stefano Majocchi
- Department of Fundamental Microbiology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | | | | | | | - Nicolas Mermod
- Department of Fundamental Microbiology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
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8
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Betts Z, Dickson AJ. Ubiquitous Chromatin Opening Elements (UCOEs) effect on transgene position and expression stability in CHO cells following methotrexate (MTX) amplification. Biotechnol J 2016; 11:554-64. [DOI: 10.1002/biot.201500159] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2015] [Revised: 08/30/2015] [Accepted: 12/02/2015] [Indexed: 11/12/2022]
Affiliation(s)
- Zeynep Betts
- The University of Manchester, Faculty of Life Sciences, Michael Smith Building; Manchester United Kingdom
| | - Alan J. Dickson
- The University of Manchester, Faculty of Life Sciences, Michael Smith Building; Manchester United Kingdom
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9
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Harraghy N, Calabrese D, Fisch I, Girod PA, LeFourn V, Regamey A, Mermod N. Epigenetic regulatory elements: Recent advances in understanding their mode of action and use for recombinant protein production in mammalian cells. Biotechnol J 2015; 10:967-78. [DOI: 10.1002/biot.201400649] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Revised: 04/20/2015] [Accepted: 05/20/2015] [Indexed: 12/18/2022]
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10
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Betts Z, Croxford AS, Dickson AJ. Evaluating the interaction between UCOE and DHFR-linked amplification and stability of recombinant protein expression. Biotechnol Prog 2015; 31:1014-25. [DOI: 10.1002/btpr.2083] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 03/17/2015] [Indexed: 11/10/2022]
Affiliation(s)
- Zeynep Betts
- Faculty of Life Sciences; University of Manchester; Michael Smith Building, Oxford Road Manchester M13 9PT UK
| | - Alexandra S Croxford
- Faculty of Life Sciences; University of Manchester; Michael Smith Building, Oxford Road Manchester M13 9PT UK
| | - Alan J Dickson
- Faculty of Life Sciences; University of Manchester; Michael Smith Building, Oxford Road Manchester M13 9PT UK
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11
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Spencer S, Gugliotta A, Koenitzer J, Hauser H, Wirth D. Stability of single copy transgene expression in CHOK1 cells is affected by histone modifications but not by DNA methylation. J Biotechnol 2015; 195:15-29. [DOI: 10.1016/j.jbiotec.2014.12.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2014] [Revised: 12/07/2014] [Accepted: 12/11/2014] [Indexed: 12/22/2022]
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12
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Impact of Using Different Promoters and Matrix Attachment Regions on Recombinant Protein Expression Level and Stability in Stably Transfected CHO Cells. Mol Biotechnol 2014; 57:138-44. [DOI: 10.1007/s12033-014-9809-2] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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13
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A PiggyBac-mediated approach for muscle gene transfer or cell therapy. Stem Cell Res 2014; 13:390-403. [PMID: 25310255 DOI: 10.1016/j.scr.2014.08.007] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 08/27/2014] [Accepted: 08/29/2014] [Indexed: 11/22/2022] Open
Abstract
An emerging therapeutic approach for Duchenne muscular dystrophy is the transplantation of autologous myogenic progenitor cells genetically modified to express dystrophin. The use of this approach is challenged by the difficulty in maintaining these cells ex vivo while keeping their myogenic potential, and ensuring sufficient transgene expression following their transplantation and myogenic differentiation in vivo. We investigated the use of the piggyBac transposon system to achieve stable gene expression when transferred to cultured mesoangioblasts and into murine muscles. Without selection, up to 8% of the mesoangioblasts expressed the transgene from 1 to 2 genomic copies of the piggyBac vector. Integration occurred mostly in intergenic genomic DNA and transgene expression was stable in vitro. Intramuscular transplantation of mouse Tibialis anterior muscles with mesoangioblasts containing the transposon led to sustained myofiber GFP expression in vivo. In contrast, the direct electroporation of the transposon-donor plasmids in the mouse Tibialis muscles in vivo did not lead to sustained transgene expression despite molecular evidence of piggyBac transposition in vivo. Together these findings provide a proof-of-principle that piggyBac transposon may be considered for mesoangioblast cell-based therapies of muscular dystrophies.
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14
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Shiue CN, Nematollahi-Mahani A, Wright APH. Myc-induced anchorage of the rDNA IGS region to nucleolar matrix modulates growth-stimulated changes in higher-order rDNA architecture. Nucleic Acids Res 2014; 42:5505-17. [PMID: 24609384 PMCID: PMC4027186 DOI: 10.1093/nar/gku183] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Chromatin domain organization and the compartmentalized distribution of chromosomal regions are essential for packaging of deoxyribonucleic acid (DNA) in the eukaryotic nucleus as well as regulated gene expression. Nucleoli are the most prominent morphological structures of cell nuclei and nucleolar organization is coupled to cell growth. It has been shown that nuclear scaffold/matrix attachment regions often define the base of looped chromosomal domains in vivo and that they are thereby critical for correct chromosome architecture and gene expression. Here, we show regulated organization of mammalian ribosomal ribonucleic acid genes into distinct chromatin loops by tethering to nucleolar matrix via the non-transcribed inter-genic spacer region of the ribosomal DNA (rDNA). The rDNA gene loop structures are induced specifically upon growth stimulation and are dependent on the activity of the c-Myc protein. Matrix-attached rDNA genes are hypomethylated at the promoter and are thus available for transcriptional activation. rDNA genes silenced by methylation are not recruited to the matrix. c-Myc, which has been shown to induce rDNA transcription directly, is physically associated with rDNA gene looping structures and the intergenic spacer sequence in growing cells. Such a role of Myc proteins in gene activation has not been reported previously.
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Affiliation(s)
- Chiou-Nan Shiue
- Clinical Research Center (KFC), Department of Laboratory Medicine and Center for Biosciences, Karolinska Institute, SE-141 86 Huddinge, Sweden
| | - Amir Nematollahi-Mahani
- Clinical Research Center (KFC), Department of Laboratory Medicine and Center for Biosciences, Karolinska Institute, SE-141 86 Huddinge, Sweden
| | - Anthony P H Wright
- Clinical Research Center (KFC), Department of Laboratory Medicine and Center for Biosciences, Karolinska Institute, SE-141 86 Huddinge, Sweden
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15
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Nishimiya D. Proteins improving recombinant antibody production in mammalian cells. Appl Microbiol Biotechnol 2013; 98:1031-42. [PMID: 24327213 DOI: 10.1007/s00253-013-5427-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/20/2013] [Accepted: 11/21/2013] [Indexed: 12/13/2022]
Abstract
Mammalian cells have been successfully used for the industrial manufacture of antibodies due to their ability to synthesize antibodies correctly. Nascent polypeptides must be subjected to protein folding and assembly in the ER and the Golgi to be secreted as mature proteins. If these reactions do not proceed appropriately, unfolded or misfolded proteins are degraded by the ER-associated degradation (ERAD) pathway. The accumulation of unfolded proteins or intracellular antibody crystals accompanied by this failure triggers the unfolded protein response (UPR), which can considerably attenuate the levels of translation, folding, assembly, and secretion, resulting in reduction of antibody productivity. Accumulating studies by omics-based analysis of recombinant mammalian cells suggest that not only protein secretion processes including protein folding and assembly but also translation are likely to be the rate-limiting factors for increasing antibody production. Here, this review describes the mechanism of antibody folding and assembly and recent advantages which could improve recombinant antibody production in mammalian cells by utilizing proteins such as ER chaperones or UPR-related proteins.
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Affiliation(s)
- Daisuke Nishimiya
- New Modality Research Laboratories, R&D Division, Daiichi Sankyo Co., Ltd., 1-2-58 Hiromachi, Shinagawa-ku, Tokyo, 140-8710, Japan,
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16
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Puttini S, van Zwieten RW, Saugy D, Lekka M, Hogger F, Ley D, Kulik AJ, Mermod N. MAR-mediated integration of plasmid vectors for in vivo gene transfer and regulation. BMC Mol Biol 2013; 14:26. [PMID: 24295286 PMCID: PMC4219123 DOI: 10.1186/1471-2199-14-26] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2013] [Accepted: 11/20/2013] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The in vivo transfer of naked plasmid DNA into organs such as muscles is commonly used to assess the expression of prophylactic or therapeutic genes in animal disease models. RESULTS In this study, we devised vectors allowing a tight regulation of transgene expression in mice from such non-viral vectors using a doxycycline-controlled network of activator and repressor proteins. Using these vectors, we demonstrate proper physiological response as consequence of the induced expression of two therapeutically relevant proteins, namely erythropoietin and utrophin. Kinetic studies showed that the induction of transgene expression was only transient, unless epigenetic regulatory elements termed Matrix Attachment Regions, or MAR, were inserted upstream of the regulated promoters. Using episomal plasmid rescue and quantitative PCR assays, we observed that similar amounts of plasmids remained in muscles after electrotransfer with or without MAR elements, but that a significant portion had integrated into the muscle fiber chromosomes. Interestingly, the MAR elements were found to promote plasmid genomic integration but to oppose silencing effects in vivo, thereby mediating long-term expression. CONCLUSIONS This study thus elucidates some of the determinants of transient or sustained expression from the use of non-viral regulated vectors in vivo.
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Affiliation(s)
- Stefania Puttini
- Institute of Biotechnology, University of Lausanne, Lausanne, Switzerland.
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17
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Arope S, Harraghy N, Pjanic M, Mermod N. Molecular characterization of a human matrix attachment region epigenetic regulator. PLoS One 2013; 8:e79262. [PMID: 24244463 PMCID: PMC3828356 DOI: 10.1371/journal.pone.0079262] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2013] [Accepted: 09/25/2013] [Indexed: 01/08/2023] Open
Abstract
Matrix attachment regions (MAR) generally act as epigenetic regulatory sequences that increase gene expression, and they were proposed to partition chromosomes into loop-forming domains. However, their molecular mode of action remains poorly understood. Here, we assessed the possible contribution of the AT-rich core and adjacent transcription factor binding motifs to the transcription augmenting and anti-silencing effects of human MAR 1–68. Either flanking sequences together with the AT-rich core were required to obtain the full MAR effects. Shortened MAR derivatives retaining full MAR activity were constructed from combinations of the AT-rich sequence and multimerized transcription factor binding motifs, implying that both transcription factors and the AT-rich microsatellite sequence are required to mediate the MAR effect. Genomic analysis indicated that MAR AT-rich cores may be depleted of histones and enriched in RNA polymerase II, providing a molecular interpretation of their chromatin domain insulator and transcriptional augmentation activities.
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Affiliation(s)
- Salina Arope
- Laboratory of Molecular Biotechnology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | - Niamh Harraghy
- Laboratory of Molecular Biotechnology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | - Milos Pjanic
- Laboratory of Molecular Biotechnology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
| | - Nicolas Mermod
- Laboratory of Molecular Biotechnology, Institute of Biotechnology, University of Lausanne, and Center for Biotechnology UNIL-EPFL, Lausanne, Switzerland
- * E-mail:
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18
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Majocchi S, Aritonovska E, Mermod N. Epigenetic regulatory elements associate with specific histone modifications to prevent silencing of telomeric genes. Nucleic Acids Res 2013; 42:193-204. [PMID: 24071586 PMCID: PMC3874193 DOI: 10.1093/nar/gkt880] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In eukaryotic cells, transgene expression levels may be limited by an unfavourable chromatin structure at the integration site. Epigenetic regulators are DNA sequences which may protect transgenes from such position effect. We evaluated different epigenetic regulators for their ability to protect transgene expression at telomeres, which are commonly associated to low or inconsistent expression because of their repressive chromatin environment. Although to variable extents, matrix attachment regions (MARs), ubiquitous chromatin opening element (UCOE) and the chicken cHS4 insulator acted as barrier elements, protecting a telomeric-distal transgene from silencing. MARs also increased the probability of silent gene reactivation in time-course experiments. Additionally, all MARs improved the level of expression in non-silenced cells, unlike other elements. MARs were associated to histone marks usually linked to actively expressed genes, especially acetylation of histone H3 and H4, suggesting that they may prevent the spread of silencing chromatin by imposing acetylation marks on nearby nucleosomes. Alternatively, an UCOE was found to act by preventing deposition of repressive chromatin marks. We conclude that epigenetic DNA elements used to enhance and stabilize transgene expression all have specific epigenetic signature that might be at the basis of their mode of action.
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Affiliation(s)
- Stefano Majocchi
- Laboratory of Molecular Biotechnology, Center for Biotechnology UNIL-EPFL, University of Lausanne, 1015 Lausanne, Switzerland
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19
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Genetic modification of dividing cells using episomally maintained S/MAR DNA vectors. MOLECULAR THERAPY. NUCLEIC ACIDS 2013; 2:e115. [PMID: 23941867 PMCID: PMC3759738 DOI: 10.1038/mtna.2013.40] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Accepted: 05/28/2013] [Indexed: 01/23/2023]
Abstract
The development of episomally maintained DNA vectors to genetically modify dividing cells efficiently and stably, without the risk of integration-mediated genotoxicity, should prove to be a valuable tool in genetic research. In this study, we demonstrate the utility of Scaffold/Matrix Attachment Region (S/MAR) DNA vectors to model the restoration of a functional wild-type copy of the gene folliculin (FLCN) implicated in the renal cancer Birt-Hogg-Dubé (BHD). Inactivation of FLCN has been shown to be involved in the development of sporadic renal neoplasia in BHD. S/MAR-modified BHD tumor cells (named UOK257-FS) show restored stable FLCN expression and have normalized downstream TGFβ signals. We demonstrate that UOK257-FS cells show a reduced growth rate in vitro and suppression of xenograft tumor development in vivo, compared with the original FLCN-null UOK257 cell line. In addition, we demonstrate that mTOR signaling in serum-starved FLCN-restored cells is differentially regulated compared with the FLCN-deficient cell. The novel UOK257-FS cell line will be useful for studying the signaling pathways affected in BHD pathogenesis. Significantly, this study demonstrates the suitability of S/MAR vectors to successfully model the functional expression of a therapeutic gene in a cancer cell line and will aid the identification of novel cancer markers for diagnosis and therapy.
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Jadhav V, Hackl M, Druz A, Shridhar S, Chung CY, Heffner KM, Kreil DP, Betenbaugh M, Shiloach J, Barron N, Grillari J, Borth N. CHO microRNA engineering is growing up: recent successes and future challenges. Biotechnol Adv 2013; 31:1501-13. [PMID: 23916872 PMCID: PMC3854872 DOI: 10.1016/j.biotechadv.2013.07.007] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2013] [Revised: 07/18/2013] [Accepted: 07/20/2013] [Indexed: 12/16/2022]
Abstract
microRNAs with their ability to regulate complex pathways that control cellular behavior and phenotype have been proposed as potential targets for cell engineering in the context of optimization of biopharmaceutical production cell lines, specifically of Chinese Hamster Ovary cells. However, until recently, research was limited by a lack of genomic sequence information on this industrially important cell line. With the publication of the genomic sequence and other relevant data sets for CHO cells since 2011, the doors have been opened for an improved understanding of CHO cell physiology and for the development of the necessary tools for novel engineering strategies. In the present review we discuss both knowledge on the regulatory mechanisms of microRNAs obtained from other biological models and proof of concepts already performed on CHO cells, thus providing an outlook of potential applications of microRNA engineering in production cell lines.
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Affiliation(s)
- Vaibhav Jadhav
- Department of Biotechnology, University of Natural Resources and Life Sciences, Vienna, Austria
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MAR elements and transposons for improved transgene integration and expression. PLoS One 2013; 8:e62784. [PMID: 23646143 PMCID: PMC3640020 DOI: 10.1371/journal.pone.0062784] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2013] [Accepted: 03/24/2013] [Indexed: 01/01/2023] Open
Abstract
Reliable and long-term expression of transgenes remain significant challenges for gene therapy and biotechnology applications, especially when antibiotic selection procedures are not applicable. In this context, transposons represent attractive gene transfer vectors because of their ability to promote efficient genomic integration in a variety of mammalian cell types. However, expression from genome-integrating vectors may be inhibited by variable gene transcription and/or silencing events. In this study, we assessed whether inclusion of two epigenetic control elements, the human Matrix Attachment Region (MAR) 1–68 and X-29, in a piggyBac transposon vector, may lead to more reliable and efficient expression in CHO cells. We found that addition of the MAR 1–68 at the center of the transposon did not interfere with transposition frequency, and transgene expressing cells could be readily detected from the total cell population without antibiotic selection. Inclusion of the MAR led to higher transgene expression per integrated copy, and reliable expression could be obtained from as few as 2–4 genomic copies of the MAR-containing transposon vector. The MAR X-29-containing transposons was found to mediate elevated expression of therapeutic proteins in polyclonal or monoclonal CHO cell populations using a transposable vector devoid of selection gene. Overall, we conclude that MAR and transposable vectors can be used to improve transgene expression from few genomic transposition events, which may be useful when expression from a low number of integrated transgene copies must be obtained and/or when antibiotic selection cannot be applied.
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Contie M, Leger O, Fouque N, Poitevin Y, Kosco-Vilbois M, Mermod N, Elson G. IL-17F co- ;expression improves cell growth characteristics and enhances recombinant protein production during CHO cell line engineering. Biotechnol Bioeng 2012; 110:1153-63. [DOI: 10.1002/bit.24763] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2012] [Revised: 09/17/2012] [Accepted: 10/08/2012] [Indexed: 12/21/2022]
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Harraghy N, Buceta M, Regamey A, Girod PA, Mermod N. Using matrix attachment regions to improve recombinant protein production. Methods Mol Biol 2012; 801:93-110. [PMID: 21987249 DOI: 10.1007/978-1-61779-352-3_7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Chinese hamster ovary (CHO) cells are the system of choice for the production of complex molecules, such as monoclonal antibodies. Despite significant progress in improving the yield from these cells, the process to the selection, identification, and maintenance of high-producing cell lines remains cumbersome, time consuming, and often of uncertain outcome. Matrix attachment regions (MARs) are DNA sequences that help generate and maintain an open chromatin domain that is favourable to transcription and may also facilitate the integration of several copies of the transgene. By incorporating MARs into expression vectors, an increase in the proportion of high-producer cells as well as an increase in protein production are seen, thereby reducing the number of clones to be screened and time to production by as much as 9 months. In this chapter, we describe how MARs can be used to increase transgene expression and provide protocols for the transfection of CHO cells in suspension and detection of high-producing antibody cell clones.
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Affiliation(s)
- Niamh Harraghy
- Laboratory of Molecular Biotechnology, University of Lausanne, Lausanne, Switzerland
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Osterlehner A, Simmeth S, Göpfert U. Promoter methylation and transgene copy numbers predict unstable protein production in recombinant chinese hamster ovary cell lines. Biotechnol Bioeng 2011; 108:2670-81. [DOI: 10.1002/bit.23216] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2011] [Revised: 04/19/2011] [Accepted: 05/05/2011] [Indexed: 02/06/2023]
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Grandjean M, Girod PA, Calabrese D, Kostyrko K, Wicht M, Yerly F, Mazza C, Beckmann JS, Martinet D, Mermod N. High-level transgene expression by homologous recombination-mediated gene transfer. Nucleic Acids Res 2011; 39:e104. [PMID: 21652640 PMCID: PMC3159483 DOI: 10.1093/nar/gkr436] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Gene transfer and expression in eukaryotes is often limited by a number of stably maintained gene copies and by epigenetic silencing effects. Silencing may be limited by the use of epigenetic regulatory sequences such as matrix attachment regions (MAR). Here, we show that successive transfections of MAR-containing vectors allow a synergistic increase of transgene expression. This finding is partly explained by an increased entry into the cell nuclei and genomic integration of the DNA, an effect that requires both the MAR element and iterative transfections. Fluorescence in situ hybridization analysis often showed single integration events, indicating that DNAs introduced in successive transfections could recombine. High expression was also linked to the cell division cycle, so that nuclear transport of the DNA occurs when homologous recombination is most active. Use of cells deficient in either non-homologous end-joining or homologous recombination suggested that efficient integration and expression may require homologous recombination-based genomic integration of MAR-containing plasmids and the lack of epigenetic silencing events associated with tandem gene copies. We conclude that MAR elements may promote homologous recombination, and that cells and vectors can be engineered to take advantage of this property to mediate highly efficient gene transfer and expression.
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Affiliation(s)
- Mélanie Grandjean
- Laboratory of Molecular Biotechnology, Center for Biotechnology UNIL-EPFL, University of Lausanne, Lausanne, Switzerland
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Harraghy N, Regamey A, Girod PA, Mermod N. Identification of a potent MAR element from the mouse genome and assessment of its activity in stable and transient transfections. J Biotechnol 2011; 154:11-20. [DOI: 10.1016/j.jbiotec.2011.04.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2011] [Revised: 04/04/2011] [Accepted: 04/13/2011] [Indexed: 01/26/2023]
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Moreno R, Martínez I, Petriz J, Nadal M, Tintoré X, Gonzalez JR, Gratacós E, Aran JM. The β-Interferon Scaffold Attachment Region Confers High-Level Transgene Expression and Avoids Extinction by Epigenetic Modifications of Integrated Provirus in Adipose Tissue-Derived Human Mesenchymal Stem Cells. Tissue Eng Part C Methods 2011; 17:275-87. [DOI: 10.1089/ten.tec.2010.0383] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Rafael Moreno
- Medical and Molecular Genetics Center, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Barcelona, Spain
| | - Itziar Martínez
- Medical and Molecular Genetics Center, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Barcelona, Spain
| | - Jordi Petriz
- Biomedical Research Unit, Institut de Recerca Hospital Universitari Vall d'Hebron, Barcelona, Spain
| | - Marga Nadal
- Translational Research Laboratory, IDIBELL-Institut Català d'Oncologia, Barcelona, Spain
| | - Xavier Tintoré
- Plastic Surgery Service, Capio Hospital General de Catalunya, Barcelona, Spain
| | - Juan Ramón Gonzalez
- Center for Research in Environmental Epidemiology (CREAL) and CIBERESP, Barcelona, Spain
| | - Eduard Gratacós
- Maternal-Fetal Medicine Department, Hospital Clinic-IDIBAPS, University of Barcelona and CIBERER, Barcelona, Spain
| | - Josep M. Aran
- Medical and Molecular Genetics Center, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), Barcelona, Spain
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Hjelmeland LM. Dark matters in AMD genetics: epigenetics and stochasticity. Invest Ophthalmol Vis Sci 2011; 52:1622-31. [PMID: 21429863 DOI: 10.1167/iovs.10-6765] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- Leonard M Hjelmeland
- Department of Ophthalmology and Vision Science, School of Medicine, University of California, Davis, California, USA.
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Argyros O, Wong SP, Fedonidis C, Tolmachov O, Waddington SN, Howe SJ, Niceta M, Coutelle C, Harbottle RP. Development of S/MAR minicircles for enhanced and persistent transgene expression in the mouse liver. J Mol Med (Berl) 2011; 89:515-29. [PMID: 21301798 DOI: 10.1007/s00109-010-0713-3] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2010] [Revised: 10/29/2010] [Accepted: 12/03/2010] [Indexed: 12/29/2022]
Abstract
We have previously described the development of a scaffold/matrix attachment region (S/MAR) episomal vector system for in vivo application and demonstrated its utility to sustain transgene expression in the mouse liver for at least 6 months following a single administration. Subsequently, we observed that transgene expression is sustained for the lifetime of the animal. The level of expression, however, does drop appreciably over time. We hypothesised that by eliminating the bacterial components in our vectors, we could improve their performance since bacterial sequences have been shown to be responsible for the immunotoxicity of the vector and the silencing of its expression when applied in vivo. We describe here the development of a minimally sized S/MAR vector, which is devoid of extraneous bacterial sequences. This minicircle vector comprises an expression cassette and an S/MAR moiety, providing higher and more sustained transgene expression for several months in the absence of selection, both in vitro and in vivo. In contrast to the expression of our original S/MAR plasmid vector, the novel S/MAR minicircle vectors mediate increased transgene expression, which becomes sustained at about twice the levels observed immediately after administration. These promising results demonstrate the utility of minimally sized S/MAR vectors for persistent, atoxic gene expression.
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Affiliation(s)
- Orestis Argyros
- Gene Therapy Research Group, Section of Molecular Medicine, National Heart and Lung Institute, Imperial College London, London, UK
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Buceta M, Galbete JL, Kostic C, Arsenijevic Y, Mermod N. Use of human MAR elements to improve retroviral vector production. Gene Ther 2010; 18:7-13. [DOI: 10.1038/gt.2010.115] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Pilbrough W, Munro TP, Gray P. Intraclonal protein expression heterogeneity in recombinant CHO cells. PLoS One 2009; 4:e8432. [PMID: 20037651 PMCID: PMC2793030 DOI: 10.1371/journal.pone.0008432] [Citation(s) in RCA: 137] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 12/02/2009] [Indexed: 11/19/2022] Open
Abstract
Therapeutic glycoproteins have played a major role in the commercial success of biotechnology in the post-genomic era. But isolating recombinant mammalian cell lines for large-scale production remains costly and time-consuming, due to substantial variation and unpredictable stability of expression amongst transfected cells, requiring extensive clone screening to identify suitable high producers. Streamlining this process is of considerable interest to industry yet the underlying phenomena are still not well understood. Here we examine an antibody-expressing Chinese hamster ovary (CHO) clone at single-cell resolution using flow cytometry and vectors, which couple light and heavy chain transcription to fluorescent markers. Expression variation has traditionally been attributed to genetic heterogeneity arising from random genomic integration of vector DNA. It follows that single cell cloning should yield a homogeneous cell population. We show, in fact, that expression in a clone can be surprisingly heterogeneous (standard deviation 50 to 70% of the mean), approaching the level of variation in mixed transfectant pools, and each antibody chain varies in tandem. Phenotypic variation is fully developed within just 18 days of cloning, yet is not entirely explained by measurement noise, cell size, or the cell cycle. By monitoring the dynamic response of subpopulations and subclones, we show that cells also undergo slow stochastic fluctuations in expression (half-life 2 to 11 generations). Non-genetic diversity may therefore play a greater role in clonal variation than previously thought. This also has unexpected implications for expression stability. Stochastic gene expression noise and selection bias lead to perturbations from steady state at the time of cloning. The resulting transient response as clones reestablish their expression distribution is not ordinarily accounted for but can contribute to declines in median expression over timescales of up to 50 days. Noise minimization may therefore be a novel strategy to reduce apparent expression instability and simplify cell line selection.
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Affiliation(s)
- Warren Pilbrough
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, Queensland, Australia
| | - Trent P. Munro
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, Queensland, Australia
- ACYTE Biotech Pty Ltd, Brisbane, Queensland, Australia
- * E-mail:
| | - Peter Gray
- Australian Institute for Bioengineering and Nanotechnology (AIBN), The University of Queensland, Brisbane, Queensland, Australia
- ACYTE Biotech Pty Ltd, Brisbane, Queensland, Australia
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