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Mossine VV, Waters JK, Hannink M, Mawhinney TP. piggyBac transposon plus insulators overcome epigenetic silencing to provide for stable signaling pathway reporter cell lines. PLoS One 2013; 8:e85494. [PMID: 24376882 PMCID: PMC3869926 DOI: 10.1371/journal.pone.0085494] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 12/04/2013] [Indexed: 12/28/2022] Open
Abstract
Genetically modified hematopoietic progenitors represent an important testing platform for a variety of cell-based therapies, pharmaceuticals, diagnostics and other applications. Stable expression of a transfected gene of interest in the cells is often obstructed by its silencing. DNA transposons offer an attractive non-viral alternative of transgene integration into the host genome, but their broad applicability to leukocytes and other "transgene unfriendly" cells has not been fully demonstrated. Here we assess stability of piggyBac transposon-based reporter expression in murine prostate adenocarcinoma TRAMP-C2, human monocyte THP-1 and erythroleukemia K562 cell lines, along with macrophages and dendritic cells (DCs) that have differentiated from the THP-1 transfects. The most efficient and stable reporter activity was observed for combinations of the transposon inverted terminal repeats and one 5'- or two cHS4 core insulators flanking a green fluorescent protein reporter construct, with no detectable silencing over 10 months of continuous cell culture in absence of any selective pressure. In monocytic THP-1 cells, the functional activity of luciferase reporters for NF-κB, Nrf2, or HIF-1α has not decreased over time and was retained following differentiation into macrophages and DCs, as well. These results imply pB as a versatile tool for gene integration in monocytic cells in general, and as a convenient access route to DC-based signaling pathway reporters suitable for high-throughput assays, in particular.
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Affiliation(s)
- Valeri V. Mossine
- Department of Biochemistry, University of Missouri, Columbia, Missouri, United States of America
- Experiment Station Chemical Labs, University of Missouri, Columbia, Missouri, United States of America
- * E-mail:
| | - James K. Waters
- Experiment Station Chemical Labs, University of Missouri, Columbia, Missouri, United States of America
| | - Mark Hannink
- Department of Biochemistry, University of Missouri, Columbia, Missouri, United States of America
| | - Thomas P. Mawhinney
- Department of Biochemistry, University of Missouri, Columbia, Missouri, United States of America
- Experiment Station Chemical Labs, University of Missouri, Columbia, Missouri, United States of America
- Department of Child Health, University of Missouri, Columbia, Missouri, United States of America
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102
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Glover JD, Taylor L, Sherman A, Zeiger-Poli C, Sang HM, McGrew MJ. A novel piggyBac transposon inducible expression system identifies a role for AKT signalling in primordial germ cell migration. PLoS One 2013; 8:e77222. [PMID: 24223709 PMCID: PMC3817190 DOI: 10.1371/journal.pone.0077222] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/09/2013] [Indexed: 01/15/2023] Open
Abstract
In this work, we describe a single piggyBac transposon system containing both a tet-activator and a doxycycline-inducible expression cassette. We demonstrate that a gene product can be conditionally expressed from the integrated transposon and a second gene can be simultaneously targeted by a short hairpin RNA contained within the transposon, both in vivo and in mammalian and avian cell lines. We applied this system to stably modify chicken primordial germ cell (PGC) lines in vitro and induce a reporter gene at specific developmental stages after injection of the transposon-modified germ cells into chicken embryos. We used this vector to express a constitutively-active AKT molecule during PGC migration to the forming gonad. We found that PGC migration was retarded and cells could not colonise the forming gonad. Correct levels of AKT activation are thus essential for germ cell migration during early embryonic development.
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Affiliation(s)
- James D Glover
- The Roslin Institute and Royal (Dick) School of Veterinary Studies, University of Edinburgh, Easter Bush Campus, Midlothian, United Kingdom
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103
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Pocanschi CL, Ehsani S, Mehrabian M, Wille H, Reginold W, Trimble WS, Wang H, Yee A, Arrowsmith CH, Bozóky Z, Kay LE, Forman-Kay JD, Rini JM, Schmitt-Ulms G. The ZIP5 ectodomain co-localizes with PrP and may acquire a PrP-like fold that assembles into a dimer. PLoS One 2013; 8:e72446. [PMID: 24039764 PMCID: PMC3765157 DOI: 10.1371/journal.pone.0072446] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 07/18/2013] [Indexed: 01/11/2023] Open
Abstract
The cellular prion protein (PrP(C)) was recently observed to co-purify with members of the LIV-1 subfamily of ZIP zinc transporters (LZTs), precipitating the surprising discovery that the prion gene family descended from an ancestral LZT gene. Here, we compared the subcellular distribution and biophysical characteristics of LZTs and their PrP-like ectodomains. When expressed in neuroblastoma cells, the ZIP5 member of the LZT subfamily was observed to be largely directed to the same subcellular locations as PrP(C) and both proteins were seen to be endocytosed through vesicles decorated with the Rab5 marker protein. When recombinantly expressed, the PrP-like domain of ZIP5 could be obtained with yields and levels of purity sufficient for structural analyses but it tended to aggregate, thereby precluding attempts to study its structure. These obstacles were overcome by moving to a mammalian cell expression system. The subsequent biophysical characterization of a homogeneous preparation of the ZIP5 PrP-like ectodomain shows that this protein acquires a dimeric, largely globular fold with an α-helical content similar to that of mammalian PrP(C). The use of a mammalian cell expression system also allowed for the expression and purification of stable preparations of Takifugu rubripes PrP-1, thereby overcoming a key hindrance to high-resolution work on a fish PrP(C).
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Affiliation(s)
- Cosmin L. Pocanschi
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Sepehr Ehsani
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Mohadeseh Mehrabian
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - Holger Wille
- Department of Biochemistry and Centre for Prions and Protein Folding Diseases, University of Alberta, Edmonton, Alberta, Canada
| | - William Reginold
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
| | - William S. Trimble
- Program in Cell Biology, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
| | - Hansen Wang
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
| | - Adelinda Yee
- Structural Genomics Consortium, Toronto, Ontario, Canada
| | | | - Zoltán Bozóky
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - Lewis E. Kay
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Julie D. Forman-Kay
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Molecular Structure and Function Program, Hospital for Sick Children, Toronto, Ontario, Canada
| | - James M. Rini
- Department of Biochemistry, University of Toronto, Toronto, Ontario, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, Ontario, Canada
| | - Gerold Schmitt-Ulms
- Tanz Centre for Research in Neurodegenerative Diseases, University of Toronto, Toronto, Ontario, Canada
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Ontario, Canada
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