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Aldrich TL, Thomas JN, Morris AE. Improved bicistronic mammalian expression vectors using expression augmenting sequence element (EASE). Cytotechnology 2011; 28:9-17. [PMID: 19003402 DOI: 10.1023/a:1008048807588] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have recently reported on the isolation of a 5.7 kb segment of Chinese hamster ovary cell genomic DNA, Expression Augmenting Sequence Element (EASE), which when used in bicistronic expression vectors allows the development of stable Chinese hamster ovary cell pools in a five to seven week time period that express high levels of recombinant protein (6-25 mug 10-6 cells/day depending on the protein). In the present study, we have mapped the activity of the EASE to a 2.1 kb region using colony forming assays and developed bicistronic expression vectors with the smaller EASE or control lambda DNA. The recovery of pools expressing the hematopoietic growth factor, FLT3 Ligand, in methotrexate-containing media took 1 to 4 weeks less when using EASE expression vectors compared with control vectors. The cell pools developed with the EASE and control vectors had similar final protein expression levels. Southern blot analysis suggested the expression cassette from the EASE containing vectors integrated in tandem arrays arranged in either head to head or head to tail fashion. By contrast, control vectors appeared to integrate with multiple interruptions to the expression vector. Thus, the EASE, within a bicistronic expression vector, appeared to facilitate tandem vector integration and reduce the time required to develop cell pools for protein expression.
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Affiliation(s)
- T L Aldrich
- Immunex Corporation, 51 University Street, Seattle, Washington, 98101, U.S.A
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Rottmann O, Antes R, Höfer P, Sommer B, Wanner G, Görlach A, Grummt F, Pirchner F. Liposome-mediated gene transfer via sperm cells. High transfer efficiency and persistence of transgenes by use of liposomes and sperm cells and a murine amplification element. J Anim Breed Genet 2011. [DOI: 10.1111/j.1439-0388.1996.tb00631.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Ma QH, Futagawa T, Yang WL, Jiang XD, Zeng L, Takeda Y, Xu RX, Bagnard D, Schachner M, Furley AJ, Karagogeos D, Watanabe K, Dawe GS, Xiao ZC. A TAG1-APP signalling pathway through Fe65 negatively modulates neurogenesis. Nat Cell Biol 2008; 10:283-94. [PMID: 18278038 DOI: 10.1038/ncb1690] [Citation(s) in RCA: 163] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2007] [Accepted: 01/21/2007] [Indexed: 11/10/2022]
Abstract
The release of amyloid precursor protein (APP) intracellular domain (AICD) may be triggered by extracellular cues through gamma-secretase-dependent cleavage. AICD binds to Fe65, which may have a role in AICD-dependent signalling; however, the functional ligand has not been characterized. In this study, we have identified TAG1 as a functional ligand of APP. We found that, through an extracellular interaction with APP, TAG1 increased AICD release and triggered Fe65-dependent activity in a gamma-secretase-dependent manner. TAG1, APP and Fe65 colocalized in the neural stem cell niche of the fetal ventricular zone. Neural precursor cells from TAG1-/-, APP-/- and TAG1-/-;APP-/- mice had aberrantly enhanced neurogenesis, which was significantly reversed in TAG1-/- mice by TAG1 or AICD but not by AICD mutated at the Fe65 binding site. Notably, TAG1 reduced normal neurogenesis in Fe65+/+ mice. Abnormally enhanced neurogenesis also occurred in Fe65-/- mice but could not be reversed by TAG1. These results describe a TAG1-APP signalling pathway that negatively modulates neurogenesis through Fe65.
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Affiliation(s)
- Quan-Hong Ma
- Institute of Molecular and Cell Biology, 61 Biopolis Drive, Proteos, Singapore 138673
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Hoelker M, Mekchay S, Schneider H, Bracket BG, Tesfaye D, Jennen D, Tholen E, Gilles M, Rings F, Griese J, Schellander K. Quantification of DNA binding, uptake, transmission and expression in bovine sperm mediated gene transfer by RT-PCR: Effect of transfection reagent and DNA architecture. Theriogenology 2007; 67:1097-107. [PMID: 17289138 DOI: 10.1016/j.theriogenology.2006.12.011] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2006] [Revised: 11/28/2006] [Accepted: 12/17/2006] [Indexed: 11/17/2022]
Abstract
In this study, we compared the transfection effectiveness of liposomes with the new transfection reagent FuGene 6 in bovine sperm mediated gene transfer (SMGT). Furthermore, we examined whether plasmid architecture affects overall efficiency by comparing two plasmids, one of them bearing an additional murine nontranscribed spacer (nts) insert (CMV-INF-tau-IRES-EGFP versus CMV-INF-tau-IRES-EGFP-nts). To accomplish that, we quantified plasmid binding and uptake to spermatozoon and transfer and expression of foreign DNA into embryos by real time PCR. More plasmids bound to spermatozoa when treated with FuGene 6 than with liposome treatment (p<0.05) reaching highest counts in plasmids bearing the nts sequence (p<0.05). Mean number of plasmids taken up was significantly (p<0.05) affected by transfection strategy (1-3 versus 15-81 versus 120-162) with plasmids bearing the nts sequence being 2-8 fold more effective (p<0.05). Culture of SMGT derived embryos up to day 9 did not result in any difference in terms of cleavage rate (64.2-84.2%) and development to blastocyst stage (18.8-26.3%) between different groups. Insert of the nts fragment significantly (p<0.05) affected mean number of transmitted plasmids to 4-cell stage embryos (44 versus 7) and relative INF-tau mRNA expression level in day 9 blastocysts (7-8 fold). However, only six blastocysts (3.6%) exhibited green fluorescence indicating low EGFP protein production. In conclusion, we were able to show effectiveness of sperm mediated gene transfer is significantly affected by choice of transfection reagent and by plasmid architecture.
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Affiliation(s)
- Michael Hoelker
- Insititute of Animal Science, Animal Breeding and Husbandry Group, University of Bonn, Endenicher Allee 15, 53115 Bonn, Germany.
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Yakoby N, Garvey A, Raskin I. Tobacco ribosomal DNA spacer element elevates Bowman-Birk inhibitor expression in tomato plants. PLANT CELL REPORTS 2006; 25:573-81. [PMID: 16408179 DOI: 10.1007/s00299-005-0101-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2005] [Revised: 11/22/2005] [Accepted: 11/26/2005] [Indexed: 05/06/2023]
Abstract
Amplification promoting sequence (aps), from tobacco rDNA, was found to induce amplification and enhances the expression of heterologous genes, consequently increasing the expression of transgenic proteins in tobacco. In this report we demonstrate that aps element also affects integration, transcription, and translation of a soybean protease inhibitor, Bowman-Birk inhibitor (BBI), in transgenic tomato plants and quantifies its effects in different expression vectors. A synthetic bbi gene was constructed, based on the wild-type gene containing two independent inhibition sites; trypsin and chymotrypsin. Transformation vectors were designed using two different promoters; the tomato fruit specific E8 promoter and the constitutively active 35S CaMV promoter. These vectors were transformed into 'Moneymaker' tomato plants. In tomato fruits and leaves, aps caused a 3-fold increase in bbi mRNA levels when compared to the lines without aps. Similar increases were obtained in plants expressing bbi controlled by E8 or 35S CaMV promoters. Also, the level of BBI protein expression in aps-transformed plants was 3 fold-higher than in plants without aps. This is the first report of aps effect on the enhanced gene expression and transgenic protein production in plant other than tobacco.
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Affiliation(s)
- Nir Yakoby
- Biotech Center, Cook College, Rutgers University, Foran Hall, 59 Dudley Road, New Brunswick, NJ 08901-8520, USA.
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Hemleben V, Volkov RA, Zentgraf U, Medina FJ. Molecular Cell Biology: Organization and Molecular Evolution of rDNA, Nucleolar Dominance, and Nucleolus Structure. PROGRESS IN BOTANY 2004. [DOI: 10.1007/978-3-642-18819-0_5] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Hu QD, Ang BT, Karsak M, Hu WP, Cui XY, Duka T, Takeda Y, Chia W, Sankar N, Ng YK, Ling EA, Maciag T, Small D, Trifonova R, Kopan R, Okano H, Nakafuku M, Chiba S, Hirai H, Aster JC, Schachner M, Pallen CJ, Watanabe K, Xiao ZC. F3/contactin acts as a functional ligand for Notch during oligodendrocyte maturation. Cell 2003; 115:163-75. [PMID: 14567914 DOI: 10.1016/s0092-8674(03)00810-9] [Citation(s) in RCA: 280] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Axon-derived molecules are temporally and spatially required as positive or negative signals to coordinate oligodendrocyte differentiation. Increasing evidence suggests that, in addition to the inhibitory Jagged1/Notch1 signaling cascade, other pathways act via Notch to mediate oligodendrocyte differentiation. The GPI-linked neural cell recognition molecule F3/contactin is clustered during development at the paranodal region, a vital site for axoglial interaction. Here, we show that F3/contactin acts as a functional ligand of Notch. This trans-extracellular interaction triggers gamma-secretase-dependent nuclear translocation of the Notch intracellular domain. F3/Notch signaling promotes oligodendrocyte precursor cell differentiation and upregulates the myelin-related protein MAG in OLN-93 cells. This can be blocked by dominant negative Notch1, Notch2, and two Deltex1 mutants lacking the RING-H2 finger motif, but not by dominant-negative RBP-J or Hes1 antisense oligonucleotides. Expression of constitutively active Notch1 or Notch2 does not upregulate MAG. Thus, F3/contactin specifically initiates a Notch/Deltex1 signaling pathway that promotes oligodendrocyte maturation and myelination.
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Affiliation(s)
- Qi-Dong Hu
- Department of Clinical Research, Singapore General Hospital, 169608, Singapore, Singapore
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Norderhaug L, Johansen FE, Sandlie I. Balanced expression of single subunits in a multisubunit protein, achieved by cell fusion of individual transfectants. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:3205-10. [PMID: 12084060 DOI: 10.1046/j.1432-1033.2002.03000.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
To establish stable cell lines that produce recombinant multisubunit proteins, it is usually necessary to cotransfect cells with several independent gene constructs. Here, we show that a stepwise fusion of individually transfected cells, results in a fused cell-line that secretes a complete multisubunit protein. Functional expression of recombinant multisubunit proteins may require a defined expression ratio between each protein subunit. The cell-fusion technology described allows a predefined expression level of each subunit. Using SIgA as a model protein we demonstrate that the majority of the fused cells inherit the molar expression ratio of the parental transfected cells. These results indicate that simplified screening of clones expressing the expected subunit ratios may be possible using the cell-fusion technology. This technology may therefore be an alternative to generic transfection methods for the establishment of cells that produce multiprotein complexes such as antibodies, receptors, ion channels and other multisubunit proteins.
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Affiliation(s)
- Lars Norderhaug
- Antibody Design AS, PO Box 190, N-1450 Nesoddtangen, Norway.
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Borisjuk N, Borisjuk L, Komarnytsky S, Timeva S, Hemleben V, Gleba Y, Raskin I. Tobacco ribosomal DNA spacer element stimulates amplification and expression of heterologous genes. Nat Biotechnol 2000; 18:1303-6. [PMID: 11101812 DOI: 10.1038/82430] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Here we show that the cis-acting genetic element aps (amplification-promoting sequence), isolated from the nontranscribed spacer region of tobacco ribosomal DNA (rDNA), increases the level of expression of recombinant proteins. Transgenic tobacco plants, transformed with expression cassettes containing the herbicide-resistant acetolactate synthase (hr-ALS) gene or the green fluorescent protein (GFP) gene fused to the aps sequence, had greater levels of corresponding messenger RNAs (mRNAs) and proteins compared to transformants lacking aps. Analysis of transgenic plants showed that aps increased the copy number and transcription of the adjacent heterologous genes and, in the case of hr-ALS, enhanced the herbicide resistance phenotype. Both the increased transgene copy number and enhanced expression were stably inherited. These data provide the first evidence that the aps sequence can be used for gene amplification in transgenic plants and possibly other multicellular organisms.
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Affiliation(s)
- N Borisjuk
- Biotech Center, Foran Hall, Cook College, Rutgers University, 59 Dudley Rd., New Brunswick, NJ 08901-8520, USA
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Brehm U, Piddlesden SJ, Gardinier MV, Linington C. Epitope specificity of demyelinating monoclonal autoantibodies directed against the human myelin oligodendrocyte glycoprotein (MOG). J Neuroimmunol 1999; 97:9-15. [PMID: 10408984 DOI: 10.1016/s0165-5728(99)00010-7] [Citation(s) in RCA: 85] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
We describe the epitope specificity of a panel of ten demyelinating monoclonal antibodies (mAb) that recognise the extracellular immunoglobulin-like domain of human myelin oligodendrocyte glycoprotein (hMOG(lgd)). All the mAbs bind to the surface of MOG-transfected fibroblasts as assessed in vitro by FACS and immunocytochemistry but failed to recognise overlapping 15-mer MOG peptides when assessed by ELISA. However, increasing peptide length to 25 amino acids revealed that four mAbs recognised epitopes within the amino acid sequence 63-100 of human MOG. In contrast, a non-demyelinating MOG-specific mAb recognised MOG by both ELISA and Western blotting but failed to stain MOG transfected fibroblasts. These observations suggest that assays based on the use of MOG-transfected cell lines will differentiate between pathogenic and non-pathogenic MOG-specific antibody responses in experimental models and human diseases of the nervous system.
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Affiliation(s)
- U Brehm
- Max-Planck-Institute of Neurobiology, Department of Neuroimmunology, Martinsried, Germany.
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Kneidl C, Baier DM, Surovoy A, Weidle UH, Müller CA, Lipps HJ, Grummt F. Fast-sorting system for cells with high-copy-number expression vectors and its use for the modulation of CML cells. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 451:473-9. [PMID: 10026914 DOI: 10.1007/978-1-4615-5357-1_73] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Affiliation(s)
- C Kneidl
- Universität Tübingen, Medizinische Klinik und Poliklinik, Germany
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Monaco L, Tagliabue R, Giovanazzi S, Bragonzi A, Soria MR. Expression of recombinant human granulocyte colony-stimulating factor in CHO dhfr- cells: new insights into the in vitro amplification expression system. Gene 1996; 180:145-50. [PMID: 8973359 DOI: 10.1016/s0378-1119(96)00435-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The in vitro amplification method for heterologous gene expression in mammalian cells is based on the stable transfection of cells with long, linear DNA molecules having several copies of complete expression units, coding for the gene of interest, linked to one terminal unit, coding for the selectable marker. DNA concatenamers containing additional expression units can also be prepared: we exploited this feature by co-polymerizing expression units coding for granulocyte colony-stimulating factor (G-CSF) with cassettes for dihydrofolate reductase (DHFR) and for neomycin (Nm) resistance, as selectable markers. We were thus able to obtain high level production of G-CSF in chinese hamster ovary (CHO) dhfr- cells by combining in vitro amplification to just one step of in vivo amplification. This approach required a considerably shorter time than the classical, stepwise amplification by methotrexate.
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Affiliation(s)
- L Monaco
- Biotechnology Unit, DIBIT, San Raffaele Scientific Institute, Milano, Italy.
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