451
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Lalwani AK, Han JJ, Walsh BJ, Zolotukhin S, Muzyczka N, Mhatre AN. Green fluorescent protein as a reporter for gene transfer studies in the cochlea. Hear Res 1997; 114:139-47. [PMID: 9447928 DOI: 10.1016/s0378-5955(97)00151-2] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
This study examined the 'humanized, red-shifted' version of the jellyfish Aequorea victoria green fluorescent protein (hrGFP) as a novel reporter for in vivo gene transfer studies in the cochlea using adeno-associated virus (AAV) vectors. Approximately 10(5) AAV vectors containing the hrGFP reporter gene were infused over 2 days or 1 week into the cochlea of the guinea pig via an osmotic minipump. Saline infused, non-infused, as well as AAV-beta-galactosidase infused guinea pigs served as the negative controls. The hrGFP transgene expression was detected as moderate intensity fluorescence easily distinguished from the background. Increased fluorescence was seen in the spiral ganglion, spiral ligament, spiral limbus, organ of Corti, and Reissner's membrane of the AAV-hrGFP infused animals. Control animals showed minimal fluorescence throughout the cochlea. Comparison of the 2 day and 1 week AAV-hrGFP infused animals showed qualitatively increased fluorescence in the 2 day animals. Background autofluorescence in the stria vascularis was noted in both the experimental and the control animals. In addition, fluorescence was detected in the contralateral cochlea of the AAV-hrGFP infused animals. Subsequent PCR analysis confirmed the presence of viral particles in the AAV-hrGFP infused cochlea as well as in the brain and the contralateral cochlea. This finding has important implications for the eventual implementation of cochlear gene therapy. The results not only reinforce the need to assess the introduction and expression of foreign genes in the target cochlea but also consider issues of viral spread, safety, and modes of gene delivery. This study establishes hrGFP as an effective reporter of gene transfer and transgene expression in the cochlea. GFP's small gene size, stability, ease of detection, and potential for diverse biological applications will be invaluable for a variety of future gene transfer and expression studies in the cochlea.
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Affiliation(s)
- A K Lalwani
- Epstein Laboratories, Department of Otolaryngology-Head and Neck Surgery, University of California San Francisco, 94117, USA.
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452
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Snyder RO, Spratt SK, Lagarde C, Bohl D, Kaspar B, Sloan B, Cohen LK, Danos O. Efficient and stable adeno-associated virus-mediated transduction in the skeletal muscle of adult immunocompetent mice. Hum Gene Ther 1997; 8:1891-900. [PMID: 9382955 DOI: 10.1089/hum.1997.8.16-1891] [Citation(s) in RCA: 168] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Recombinant adeno-associated virus (rAAV) vectors were evaluated for gene transfer into the skeletal muscle of adult immunocompetent mice. A study using a vector encoding nuclear localized beta-galactosidase (rAAV-nls-lacZ) examined: (i) the efficiency and duration of transgene expression; (ii) the status of the AAV genome in the transduced fibers; and (iii) the possibility of improving gene transfer by inducing muscle regeneration. In the absence of regeneration, the injection of 1.7 x 10(7) particles in the quadriceps resulted in gene transfer to 10-70% of myofibers. Histological analysis indicated that the vector was able to reach myofiber nuclei distant from the injection point. Cellular infiltrates were absent at early time points but became conspicuous in the vicinity of some positive fibers at 4-8 weeks and subsided by 26 weeks. Southern analysis indicated that one to three copies of the vector genome were present per cell genome equivalent. They were associated with high-molecular-weight DNA in the form of tandem oligomers or interlocked circles. Gene transfer was not facilitated in the regenerating muscle. Rather, an early inflammatory response resulted in the elimination of most positive fibers after 8 weeks. The presence of regenerated fibers with beta-galactosidase-positive nuclei suggested that myoblasts had been transduced and were able to fuse to form new fibers. Gene transfer in the absence of immune reactions against the transgene product was studied by injecting mice with a rAAV carrying the murine erythropoietin (mEpo) cDNA. Dose-dependent elevation in the hematocrit was measured for over 200 days and corresponded to 5- to 20-fold increases in plasma Epo levels. We conclude that AAV vectors efficiently and stably transduce post-mitotic muscle fibers and myoblasts in vivo.
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Affiliation(s)
- R O Snyder
- Cell Genesys Inc., Foster City, CA 94404, USA
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453
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Chishima T, Miyagi Y, Li L, Tan Y, Baranov E, Yang M, Shimada H, Moossa AR, Hoffman RM. Use of histoculture and green fluorescent protein to visualize tumor cell host interaction. In Vitro Cell Dev Biol Anim 1997; 33:745-7. [PMID: 9466677 DOI: 10.1007/s11626-997-0151-x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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454
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Kim CH, Oh Y, Lee TH. Codon optimization for high-level expression of human erythropoietin (EPO) in mammalian cells. Gene 1997; 199:293-301. [PMID: 9358069 DOI: 10.1016/s0378-1119(97)00384-3] [Citation(s) in RCA: 109] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Codon bias has been observed in many species. The usage of selective codons in a given gene is positively correlated with its expression efficiency. As an experimental approach to study codon-usage effects on heterologous gene expression in mammalian cells, we designed two human erythropoietin (EPO) genes, one in which native codons were systematically substituted with codons frequently found in highly expressed human genes and the other with codons prevalent in yeast genes. Relative performances of the re-engineered EPO genes were evaluated with various combinations of promoters and signal leader sequences. Under the comparable set of combinations, mature EPO gene with human high-frequency codons gave a considerably higher level of expression than that with yeast high-frequency codons. However, the levels of EPO expression varied, depending on the alternate combinations. Since the promoters and the signal leader sequences that we used are known to be equally efficient in gene expression, we hypothesized that the varied expression levels were due to the linear sequence between the promoter and the coding gene sequence. To test this possibility, we designed the EPO gene with hybrid codon usage in which the 5'-proximal region of the EPO gene was synthesized with yeast-biased codons and the rest with human-biased codons. This codon-usage hybrid EPO gene substantially enhanced the level of EPO transcripts and proteins up to 2.9-fold and 13.8-fold, respectively, when compared to the level reached by the original counterpart. Our results suggest that the linear sequence between the promoter and the 5'-proximal region of a gene plays an important role in achieving high-level expression in mammalian cells.
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Affiliation(s)
- C H Kim
- Biotech Research Institute, LG Chem, Taejeon, South Korea
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455
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Long Q, Meng A, Wang H, Jessen JR, Farrell MJ, Lin S. GATA-1 expression pattern can be recapitulated in living transgenic zebrafish using GFP reporter gene. Development 1997; 124:4105-11. [PMID: 9374406 DOI: 10.1242/dev.124.20.4105] [Citation(s) in RCA: 276] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In this study, DNA constructs containing the putative zebrafish promoter sequences of GATA-1, an erythroid-specific transcription factor, and the green fluorescent protein reporter gene, were microinjected into single-cell zebrafish embryos. Erythroid-specific activity of the GATA-1 promoter was observed in living embryos during early development. Fluorescent circulating blood cells were detected in microinjected embryos 24 hours after fertilization and were still present in 2-month-old fish. Germline transgenic fish obtained from the injected founders continued to express green fluorescent protein in erythroid cells in the F1 and F2 generations. The green fluorescent protein expression patterns in transgenic fish were consistent with the pattern of GATA-1 mRNA expression detected by RNA in situ hybridization. These transgenic fish have allowed us to isolate, by fluorescence-activated cell sorting, the earliest erythroid progenitor cells from developing embryos for in vitro studies. By generating transgenic fish using constructs containing other zebrafish promoters and green fluorescent protein reporter gene, it should be possible to visualize the origin and migration of any lineage-specific progenitor cells in a living embryo.
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Affiliation(s)
- Q Long
- Institute of Molecular Medicine and Genetics & Department of Biochemistry and Molecular Biology, Medical College of Georgia, Augusta 30912, USA
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456
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Chishima T, Yang M, Miyagi Y, Li L, Tan Y, Baranov E, Shimada H, Moossa AR, Penman S, Hoffman RM. Governing step of metastasis visualized in vitro. Proc Natl Acad Sci U S A 1997; 94:11573-6. [PMID: 9326651 PMCID: PMC23541 DOI: 10.1073/pnas.94.21.11573] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Metastasis is the ultimate life-threatening stage of cancer. The lack of accurate model systems thwarted studies of the metastatic cell's basic biology. To follow continuously the succeeding stages of metastatic colony growth, we heritably labeled cells from the human lung adenocarcinoma cell line ANIP 973 with green fluorescent protein (GFP) by transfection with GFP cDNA. Labeled cells were then injected intravenously into nude mice, where, by 7 days, they formed brilliantly fluorescing metastatic colonies on mouse lung [Chishima, T., Miyagi, Y., Wang, X., Yang, M., Tan, Y., Shimada, H., Moossa, A. R. & Hoffman, R. M. (1997) Clin. Exp. Metastasis 15, 547-552]. The seeded lung tissue was then excised and incubated in the three-dimensional sponge-gel-matrix-supported histoculture that maintained the critical features of progressive in vivo tumor colonization while allowing continuous access for measurement and manipulation. Tumor progression was continuously visualized by GFP fluorescence in the same individual cultures over a 52-day period, during which the tumors spread throughout the lung. Histoculture tumor colonization was selective for lung cancer cells to grow on lung tissue, because no growth occurred on histocultured mouse liver tissue, which was also observed in vivo. The ability to support selective organ colonization in histoculture and visualize tumor progression by GFP fluorescence allows the in vitro study of the governing processes of metastasis [Kuo, T.-H., Kubota, T., Watanbe, M., Furukawa, T., Teramoto, T., Ishibiki, K., Kitajima, M., Moossa, A. R., Penman, S. & Hoffman, R. M. (1995) Proc. Natl. Acad. Sci. USA 92, 12085-12089]. The results presented here provide significant, new opportunities to understand and to develop treatments that prevent and possibly reverse metastasis.
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Affiliation(s)
- T Chishima
- Department of Surgery, Yokohama City University School of Medicine, Yokohama 231, Japan
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457
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Tseng WC, Haselton FR, Giorgio TD. Transfection by cationic liposomes using simultaneous single cell measurements of plasmid delivery and transgene expression. J Biol Chem 1997; 272:25641-7. [PMID: 9325286 DOI: 10.1074/jbc.272.41.25641] [Citation(s) in RCA: 120] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Cationic liposomes are potentially important gene transfer vehicles, although their application has been limited by relatively low efficiency of transgene expression. Single cell quantitative methods, such as those used in this study, should permit a more detailed understanding of the relationships between delivered plasmid and transgene expression. Intracellular plasmid delivery and transgene expression were measured simultaneously using photoconjugated ethidium monoazide as an intracellular plasmid delivery marker and green fluorescent protein (GFP(S65T)) as a transgene expression marker. Quantitative flow cytometry was used to estimate plasmid copy number and GFP(S65T) molecules in single cells. The plasmid was delivered to HeLa cells with a cationic liposome vehicle containing 1,2-dioleoyloxy-3-trimethylammonium-propane and dioleoylphosphatidylethanolamine (1:1 mol/mol). Treatment was carried out continuously for 24 h. Flow cytometry measurements on 20, 000 cells were performed during treatment and for 48 h post-treatment. On a single cell basis, transgene expression efficiency and average GFP(S65T) expression level increased with intracellular plasmid copy number. After 3-h exposure to the liposomal vector, more than 95% of the cells were positive for plasmid entry, but none had detectable transgene expression. Maximum transgene expression was achieved at 24 h and remained unchanged at the 72-h measurement. At 24 h, the average positive cell contained 1.6 x 10(5) plasmid copies and 2.3 x 10(6) GFP(S65T) molecules. Importantly, the measurement strategies revealed that transgene expression varied widely within the entire cell population. Although only 30% of all cells expressed transgene, the subpopulation of cells that rapidly incorporated the vector demonstrated 100% efficiency in transgene expression. This study identifies parameters that modulate highly efficient transgene expression from plasmid delivery by cationic liposomes.
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Affiliation(s)
- W C Tseng
- Department of Chemical, Vanderbilt University, Nashville, Tennessee 37235, USA
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458
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Misteli T, Spector DL. Applications of the green fluorescent protein in cell biology and biotechnology. Nat Biotechnol 1997; 15:961-4. [PMID: 9335045 DOI: 10.1038/nbt1097-961] [Citation(s) in RCA: 235] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The recent emergence of an autofluorescent protein, the green fluorescent protein (GFP), has opened the door for the convenient use of intact living cells and organisms as experimental systems in fields ranging from cell biology to biomedicine. We present an overview of some of the major applications of GFP, namely its use in protein tagging and in monitoring gene expression as well as its potential in a variety of biological screens.
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Affiliation(s)
- T Misteli
- Cold Spring Harbor Laboratory, NY 11724, USA.
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459
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Abstract
The use of reporters such as green fluorescent protein (GFP) and firefly luciferase permit highly sensitive and nondestructive monitoring of gene transfer and expression. Modifications in GFP which increase intensity and thermostability, as well as alter its spectral qualities, have facilitated the use of GFP in a variety of gene transfer methods. Improvements in imaging technologies and their increased application in biological research have allowed the expanded use of luciferase-based reporters in gene transformation, particularly in genetic screens and in monitoring temporal changes in gene expression.
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Affiliation(s)
- S Welsh
- Scripps Research Institute, Department of Cell Biology, La Jolla, CA 92037, USA.
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460
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Lippincott-Schwartz J, Smith CL. Insights into secretory and endocytic membrane traffic using green fluorescent protein chimeras. Curr Opin Neurobiol 1997; 7:631-9. [PMID: 9384543 DOI: 10.1016/s0959-4388(97)80082-7] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Green fluorescent fusion proteins, which can be visualized in the unperturbed environment of a living cell, have become important reporter molecules for studying protein localization and trafficking within secretory and endocytic membranes of living cells. They have been used in a wide variety of applications, including time-lapse imaging, double-labeling and photobleach experiments. Results from such work are clarifying the steps involved in the formation, translocation and fusion of transport intermediates, are defining the roles for microtubules in membrane transport, and are providing insights into the mechanisms of protein retention and localization within organelles. In so doing, they have changed our thinking about the temporal and spatial relationships between subcellular membrane structures and the morphogenesis of secretory and endocytic organelles.
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Affiliation(s)
- J Lippincott-Schwartz
- Cell Biology and Metabolism Branch, National Institute of Child Health and Human Development (NICHD), National Institutes of Health (NIH), Bethesda, Maryland 20892, USA.
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461
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Miyoshi H, Takahashi M, Gage FH, Verma IM. Stable and efficient gene transfer into the retina using an HIV-based lentiviral vector. Proc Natl Acad Sci U S A 1997; 94:10319-23. [PMID: 9294208 PMCID: PMC23360 DOI: 10.1073/pnas.94.19.10319] [Citation(s) in RCA: 397] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The development of methods for efficient gene transfer to terminally differentiated retinal cells is important to study the function of the retina as well as for gene therapy of retinal diseases. We have developed a lentiviral vector system based on the HIV that can transduce terminally differentiated neurons of the brain in vivo. In this study, we have evaluated the ability of HIV vectors to transfer genes into retinal cells. An HIV vector containing a gene encoding the green fluorescent protein (GFP) was injected into the subretinal space of rat eyes. The GFP gene under the control of the cytomegalovirus promoter was efficiently expressed in both photoreceptor cells and retinal pigment epithelium. However, the use of the rhodopsin promoter resulted in expression predominantly in photoreceptor cells. Most successfully transduced eyes showed that photoreceptor cells in >80% of the area of whole retina expressed the GFP. The GFP expression persisted for at least 12 weeks with no apparent decrease. The efficient gene transfer into photoreceptor cells by HIV vectors will be useful for gene therapy of retinal diseases such as retinitis pigmentosa.
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Affiliation(s)
- H Miyoshi
- Laboratory of Genetics, The Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
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462
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Ali RR, Reichel MB, Hunt DM, Bhattacharya SS. Gene therapy for inherited retinal degeneration. Br J Ophthalmol 1997; 81:795-801. [PMID: 9422936 PMCID: PMC1722319 DOI: 10.1136/bjo.81.9.795] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Affiliation(s)
- R R Ali
- Department of Molecular Genetics, Institute of Ophthalmology, UCL, London
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463
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Grant CA, Ponnazhagan S, Wang XS, Srivastava A, Li T. Evaluation of recombinant adeno-associated virus as a gene transfer vector for the retina. Curr Eye Res 1997; 16:949-56. [PMID: 9288458 DOI: 10.1076/ceyr.16.9.949.5046] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
PURPOSE To evaluate recombinant adeno-associated virus (AAV) as an in vivo gene transfer vector for the retina. METHODS A recombinant AAV, vCMVp-lacZ, in which the bacterial beta-galactosidase reporter gene (lacZ) was placed under the control of a cytomegalovirus (CMV) early promoter, was injected into the vitreous body or the subretinal space of mouse eyes. The reporter gene expression was followed by histochemical analyses from 10 to 100 days post-injection. The effect of several variables on the extent of AAV-mediated gene transfer was examined, including routes of delivery, presence of an underlying mutation that caused retinal degeneration, and prior treatment with hydroxyurea. RESULTS As measured by reporter gene expression, the AAV vector mediated gene transfer to three major cell types in the retina: the retinal pigment epithelium (RPE), ganglion cells and photoreceptor cells. Following a single injection, more than half of the total retinal areas were typically positive for gene transfer. Reporter gene expression was stable for at least 3 months, the farthest time point examined. Gene transfer to photoreceptor cells was observed only following subretinal delivery, and was greatly enhanced in mice undergoing early retinal degeneration. Cells in the inner nuclear layer were rarely transduced. Systemic administration of a genotoxic drug, hydroxyurea, 2 days prior to AAV delivery did not affect the patterns and extent of reporter gene expression. There was minimal histopathology associated with AAV transduction in the retinas of recipient mice, as determined by light microscopy. CONCLUSION Recombinant AAV mediates efficient gene transfer to RPE and ganglion cells, and to photoreceptor cells under certain conditions. Persistence of transgene expression is of long duration and without apparent histopathology. The greater stability, lower cytopathicity, and the ability to transduce retinal ganglion cells are three distinct features of the AAV vector compared to current adenovirus-based vectors.
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Affiliation(s)
- C A Grant
- Berman-Gund Laboratory for the Study of Retinal Degenerations, Harvard Medical School, Massachusetts Eye and Ear Infirmary, Boston 02114, USA
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464
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Chishima T, Miyagi Y, Wang X, Baranov E, Tan Y, Shimada H, Moossa AR, Hoffman RM. Metastatic patterns of lung cancer visualized live and in process by green fluorescence protein expression. Clin Exp Metastasis 1997; 15:547-52. [PMID: 9247257 DOI: 10.1023/a:1018431128179] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We demonstrate here the visualization of human lung cancer metastasis live and in process in nude mice by green fluorescent protein (GFP) expression. The human lung adenocarcinoma cell line Anip 973 stably transfected with the humanized GFP-S65T cDNA was selected for very bright green fluorescence. GFP-transfected lung cancer cells were initially inoculated subcutaneously in nude mice. Five weeks after transplantation, the resulting tumor had reached over 1 cm in diameter and had very bright GFP fluorescence. Fragments of subcutaneous tumor were implanted onto the visceral pleura of the left lung of nude mice by surgical orthotopic implantation (SOI) of histologically-intact tissue via transverse thoracotomy. The ipsilateral resulting tumor was highly fluorescent due to GFP expression. GFP expression allowed the visualization of the advancing margin of the ipsilateral tumor into the fresh normal lung tissue. Lymphogenous and direct-seeding metastases in the pulmonary hilum, cervical lymph nodes, the mediastinum and contralateral pleural cavity and contralateral lung in the SOI-treated mice were brightly visualized by GFP expression in fresh tissue. GFP-transfected and untransfected tumor had similar metastatic characteristics suggesting that GFP expression had no effect on metastasis itself. The results with the GFP-transfected tumor cells, combined with the use of SOI, demonstrate a fundamental advance in the visualization and study of lung cancer metastasis in process.
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Affiliation(s)
- T Chishima
- Department of Surgery, Yokohama City University School of Medicine, Yokohama, Japan
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465
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Retroviral-Mediated Transfer of the Green Fluorescent Protein Gene Into Murine Hematopoietic Cells Facilitates Scoring and Selection of Transduced Progenitors In Vitro and Identification of Genetically Modified Cells In Vivo. Blood 1997. [DOI: 10.1182/blood.v90.5.1777] [Citation(s) in RCA: 175] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractWe have investigated the utility of the green fluorescent protein (GFP) to serve as a marker to assess retroviral gene transfer into hematopoietic cells and as a tool to identify and enrich for cells expressing high levels of the vector-encoded transcript. GFP, by virtue of a naturally occurring chromophore encoded in its primary sequence, displays autonomous fluorescence, thus eliminating the need for antibody or cytochemical staining to detect its expression. A bicistronic murine stem cell virus (MSCV)-based retroviral vector was constructed containing the GFP cDNA and a mutant, human dihydrofolate reductase gene. High-titer, ecotropic retroviral producer cells free of replication competent virus were generated and used to transduce murine bone marrow cells by cocultivation. Within 24 hours after completion of the transduction procedure, a high proportion (40% to 70%) of the marrow cells were intensely fluorescent compared to mock-transduced cells or cells transduced with a control retrovirus. Erythroid and myeloid hematopoietic colonies derived from GFP-transduced marrow were easily scored for retroviral gene transfer by direct in situ fluorescence microscopy. Clonogenic progenitors expressing increased levels of antifolate drug resistance could be enriched from the GFP-transduced marrow population by fluorescence activated cell sorting of cells expressing high levels of GFP. In vivo, splenic hematopoietic colonies and peripheral blood cells from animals transplanted with GFP-transduced marrow displayed intense fluorescence. These results show that GFP is an excellent marker for scoring and tracking gene-modified hematopoietic cells and for allowing rapid selection and enrichment of transduced cells expressing high levels of the transgene.
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466
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Kandel ES, Chang BD, Schott B, Shtil AA, Gudkov AV, Roninson IB. Applications of green fluorescent protein as a marker of retroviral vectors. SOMATIC CELL AND MOLECULAR GENETICS 1997; 23:325-40. [PMID: 9546076 DOI: 10.1007/bf02674280] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The Green Fluorescent Protein (GFP) of Aequorea victoria is used as a vital fluorescent tag for the detection and isolation of genetically modified cells. Several modified variants of GFP were tested as marker genes in retroviral vectors containing different backbones and promoter combinations. Constructs allowing for reliable detection of GFP fluorescence and the expression of a cotransduced gene from a strong promoter were identified. Cells harboring such constructs are detectable by flow cytometry, fluorescence microscopy and multi-well fluorescence reading. GFP expression in transduced cells is stable both in vitro and in vivo, and long-term dynamics of GFP-positive fractions in a mixed population can be used to monitor the biological effects of a cotransduced gene. Selection of cells with the highest GFP fluorescence enriches for multiply infected cells. The use of different GFP variants allows one to monitor simultaneously two cell populations transduced with vectors carrying GFPs that differ in their fluorescence intensity or spectral properties and to identify doubly transduced cells. In addition, transcription of an inducible promoter positioned in the opposite orientation to GFP can be monitored by the inhibition of GFP fluorescence. Thus, GFP provides a useful marker for gene transfer by retroviral vectors and extends the range of applications for retroviral transduction.
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Affiliation(s)
- E S Kandel
- Department of Molecular Genetics, University of Illinois at Chicago 60607-7170, USA
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467
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Jöns A, Mettenleiter TC. Green fluorescent protein expressed by recombinant pseudorabies virus as an in vivo marker for viral replication. J Virol Methods 1997; 66:283-92. [PMID: 9255739 DOI: 10.1016/s0166-0934(97)00065-7] [Citation(s) in RCA: 49] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
We isolated and characterized a pseudorabies virus (PrV) mutant expressing an engineered green fluorescent protein (GFP) optimized for expression in human cells. The GFP DNA was inserted in the non-essential glycoprotein G (gG) gene of the attenuated PrV strain Bartha. The coding sequence was cloned in frame behind the first seven codons of the gG gene under control of the strong gG promotor. On excitation with blue light, live cells infected with the recombinant PrV B80eGFP exhibited bright fluorescence when examined microscopically using filters for FITC fluorescence. In fixed samples detection sensitivity was increased by immunofluorescence using an anti-GFP antibody. Specifically labelled PrV mutants have been used successfully as transsynaptic circuit tracers for definition of central command neurons in the brain (Jansen et al., 1995. Central command neurons of the sympathetic nervous system: basis of the fight-or-flight response. Science 270, 644-646). Availability of this recombinant allows the study of even more complex interactions using differentially labelled PrV mutants, and provides a means to monitor viral replication and spread without destruction of the cell.
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Affiliation(s)
- A Jöns
- Institute of Molecular and Cellular Virology, Friedrich-Loeffler-Institutes, Insel Riems, Germany
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468
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Flannery JG, Zolotukhin S, Vaquero MI, LaVail MM, Muzyczka N, Hauswirth WW. Efficient photoreceptor-targeted gene expression in vivo by recombinant adeno-associated virus. Proc Natl Acad Sci U S A 1997; 94:6916-21. [PMID: 9192666 PMCID: PMC21259 DOI: 10.1073/pnas.94.13.6916] [Citation(s) in RCA: 286] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/1997] [Accepted: 04/08/1997] [Indexed: 02/04/2023] Open
Abstract
We describe a general approach for achieving efficient and cell type-specific expression of exogenous genes in photoreceptor cells of the mammalian retina. Recombinant adeno-associated virus (rAAV) vectors were used to transfer the bacterial lacZ gene or a synthetic green fluorescent protein gene (gfp) to mouse or rat retinas after injection into the subretinal space. Using a proximal murine rod opsin promoter (+86 to -385) to drive expression, reporter gene product was found exclusively in photoreceptors, not in any other retinal cell type or in the adjacent retinal pigment epithelium. GFP-expressing photoreceptors typically encompassed 10-20% of the total retinal area after a single 2-microl injection. Photoreceptors were transduced with nearly 100% efficiency in the region directly surrounding the injection site. We estimate approximately 2.5 million photoreceptors were transduced as a result of the single subretinal inoculation. This level of gene transfer and expression suggests the feasibility of genetic therapy for retinal disease. The gfp-containing rAAV stock was substantially free of both adenovirus and wild-type AAV, as judged by plaque assay and infectious center assay, respectively. Thus, highly purified, helper virus-free rAAV vectors can achieve high-frequency tissue-specific transduction of terminally differentiated, postmitotic photoreceptor cells.
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Affiliation(s)
- J G Flannery
- School of Optometry and Neuroscience Group, University of California, Berkeley, CA 94720, USA
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469
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470
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Smith GM, Berry RL, Yang J, Tanelian D. Electrophysiological analysis of dorsal root ganglion neurons pre- and post-coexpression of green fluorescent protein and functional 5-HT3 receptor. J Neurophysiol 1997; 77:3115-21. [PMID: 9212261 DOI: 10.1152/jn.1997.77.6.3115] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Aequorea green fluorescent protein (GFP) is an excellent marker to examine genetically altered live cells in whole animals or culture. Its potential use in identifying genetically modified neurons, however, has not been investigated extensively. To examine the usefulness, toxicity, and potential electrophyiological effects of GFP expression in neurons, we generated adenovirus containing the mGFP4 cDNA. One week after virus transfection of dorsal root ganglion neurons (DRG), 10% of postnatal DRG neurons appeared brightly fluorescent, labelling the soma and neurites. Temporal examination of these neurons demonstrated no toxicity to DRG neurons even after several weeks in culture with repeated daily epifluorescent exposure. Electrophysiological analysis and comparison of control and viral exposed (GFP- and GFP+) DRG neurons did not demonstrate any differences in whole cell resistance, resting potential, action potential (AP) threshold, AP duration, AP amplitude, or whole cell capacitance. To investigate the usefulness of GFP as a marker for identifying neurons genetically altered to express a novel neurotransmitter receptor, a second adenovirus construct was generated containing both GFP and serotonin type 3 (5-HT3) receptor cDNAs. Transfection of DRG neurons with this virus produced an inward current in the presence of serotonin only in DRG neurons that were GFP-positive. It is concluded that adenoviral transfection of neurons with GFP, for cellular labeling, and coexpression of GFP-neurotransmitter constructs are safe, nontoxic, methods for electrophysiologically investigating neurons over several weeks. The uniqueness of the vector used in these experiments is that it was constructed to express GFP in a second cassette so that it would label the transduced cells, but have no potential for interfering with the function of the foreign 5-HT3 receptor.
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Affiliation(s)
- G M Smith
- The Eugene McDermott Center for Pain Management, Department of Anesthesiology and Pain Management, University of Texas Southwestern Medical Center, Dallas 75235-9068, USA
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471
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Wang DS, Deng T, Shaw G. Membrane binding and enzymatic activation of a Dbl homology domain require the neighboring pleckstrin homology domain. Biochem Biophys Res Commun 1997; 234:183-9. [PMID: 9168986 DOI: 10.1006/bbrc.1997.6589] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Dbl-homology (DH) domains are invariably located immediately N-terminal to a pleckstrin homology (PH) domain. To understand the functional relationship between these two domains we expressed the DH domain alone, the PH domain alone, and the DH-PH combination of the invasion inducing protein Tiam-1 fused to glutathione-S-transferase (GST) or green fluorescent protein (GFP). We found that the GST-DH-PH and the GST-PH constructs bind to preparations of brain membranes and to the beta gamma subunits of trimeric G proteins in vitro, while the GST-DH and GST control do not. The GFP-DH-PH and GFP-PH constructs are localized to peripheral membranes of COS-7 cells in vivo, while GFP and GFP-DH domain constructs are found diffusely in the cytoplasm. The DH-PH domain combination activates Jun N-terminal kinase (JNK) strongly, but the DH domain alone and the PH domain alone have little effect. We conclude that membrane localization and enzymatic activation of the DH domain require the adjacent PH domain.
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Affiliation(s)
- D S Wang
- Department of Neuroscience, University of Florida College of Medicine, Gainesville 32610, USA
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472
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Clark KR, Sferra TJ, Johnson PR. Recombinant adeno-associated viral vectors mediate long-term transgene expression in muscle. Hum Gene Ther 1997; 8:659-69. [PMID: 9113506 DOI: 10.1089/hum.1997.8.6-659] [Citation(s) in RCA: 132] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
Gene transfer to muscle holds overt promise for the treatment of inherited myopathies, lysosomal storage disorders, and serum protein deficiencies. In addition, muscle could provide a reservoir for delivery of therapeutic molecules like blood clotting factors, erythropoietin, or insulin. To date, successful gene transfer to muscle has been limited by the inefficiency of the vector delivery systems and the transient nature of gene expression. In this paper, we show that a vector based on recombinant adeno-associated virus (rAAV) can efficiently transduce adult mouse skeletal muscle. Transduced myofibers escape immune elimination and transgene expression is robust beyond 5 months. Importantly, input vector DNA appears to undergo conversion from single-stranded genomes to high-molecular-weight concatameric forms. These data suggest that rAAV might have a significant advantage over many other viral and nonviral gene delivery methods, and holds significant promise as a vector for gene transfer to mature muscle.
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Affiliation(s)
- K R Clark
- Children's Hospital Research Foundation, Columbus, OH, USA
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473
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Haseloff J, Siemering KR, Prasher DC, Hodge S. Removal of a cryptic intron and subcellular localization of green fluorescent protein are required to mark transgenic Arabidopsis plants brightly. Proc Natl Acad Sci U S A 1997; 94:2122-7. [PMID: 9122158 PMCID: PMC20051 DOI: 10.1073/pnas.94.6.2122] [Citation(s) in RCA: 901] [Impact Index Per Article: 33.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The green fluorescent protein (GFP) from the jellyfish Aequorea victoria is finding wide use as a genetic marker that can be directly visualized in the living cells of many heterologous organisms. We have sought to express GFP in the model plant Arabidopsis thaliana, but have found that proper expression of GFP is curtailed due to aberrant mRNA processing. An 84-nt cryptic intron is efficiently recognized and excised from transcripts of the GFP coding sequence. The cryptic intron contains sequences similar to those required for recognition of normal plant introns. We have modified the codon usage of the gfp gene to mutate the intron and to restore proper expression in Arabidopsis. GFP is mainly localized within the nucleoplasm and cytoplasm of transformed Arabidopsis cells and can give rise to high levels of fluorescence, but it proved difficult to efficiently regenerate transgenic plants from such highly fluorescent cells. However, when GFP is targeted to the endoplasmic reticulum, transformed cells regenerate routinely to give highly fluorescent plants. These modified forms of the gfp gene are useful for directly monitoring gene expression and protein localization and dynamics at high resolution, and as a simply scored genetic marker in living plants.
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Affiliation(s)
- J Haseloff
- Division of Cell Biology, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom
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474
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Xiao X, Li J, McCown TJ, Samulski RJ. Gene transfer by adeno-associated virus vectors into the central nervous system. Exp Neurol 1997; 144:113-24. [PMID: 9126160 DOI: 10.1006/exnr.1996.6396] [Citation(s) in RCA: 158] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Adeno-associated virus (AAV) vectors are derived from a nonpathogenic and defective human parvovirus. Although currently unable to display the integration specificity featured by its wild-type parent, the recombinant AAV (rAAV) system has continued to attract enormous interest primarily due to its unique features such as safety, high titers, broad host range, transduction of quiescent cells, and vector integration. Recently, rAAV-mediated in vivo gene transfers have demonstrated efficient long-term transduction (from 3 months to more than 1.5 years) and lack of cytotoxicity and cellular immune responses in the target tissues, especially in the CNS. Alternative approaches using rAAV plasmid DNA in nonviral gene delivery systems also generated promising results. Propelled by various efforts to improve the system, rAAV vectors will provide numerous opportunities to explore the potential therapeutic applications in humans.
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Affiliation(s)
- X Xiao
- Gene Therapy Center, University of North Carolina at Chapel Hill 27599, USA
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475
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Phillips MI, Mohuczy-Dominiak D, Coffey M, Galli SM, Kimura B, Wu P, Zelles T. Prolonged reduction of high blood pressure with an in vivo, nonpathogenic, adeno-associated viral vector delivery of AT1-R mRNA antisense. Hypertension 1997; 29:374-80. [PMID: 9039130 DOI: 10.1161/01.hyp.29.1.374] [Citation(s) in RCA: 57] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
To produce a prolonged decrease in blood pressure, we have developed a nonpathogenic adeno-associated viral vector (AAV) with the antisense DNA for AT1-R. AAV has many advantages over other viral vectors. AAV does not stimulate inflammation or immune reaction. AAV enters nondividing cells and does not replicate. Therefore, it is an appropriate choice for gene therapy. Recombinant AAV was prepared with a cassette containing a cytomegalovirus promoter and the cDNA for the AT1 receptor inserted in the antisense direction. The cassette was packaged in the virion. Stable transfection of NG108-15 cells with the PAAV-AS (plasmid AAV) antisense to AT1-R produced a significant reduction in AT1 receptors. A single injection of the rAAV-AS (viral vector) was made in adult spontaneously hypertensive rats, either directly in the hypothalamus (1 microL) or in the lateral ventricles (5 microL). The result shows that there is a significant decrease of blood pressure (approximately 23 +/- 2 mm Hg) for up to 9 weeks after injection. Control injections of mock vector produced no change in blood pressure during the same time period in age-matched controls. In young spontaneously hypertensive rats (3 weeks), a single intracardiac injection of recombinant rAAV-AS reduced blood pressure and slowed the development of hypertension compared with controls (P < .01). The results suggest that a prolonged reduction in high blood pressure can be achieved with AAV vectors delivering antisense to inhibit AT1 receptors with a single administration.
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Affiliation(s)
- M I Phillips
- Department of Physiology, College of Medicine, University of Florida, Gainesville 32610, USA.
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476
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Phillips MI. Antisense inhibition and adeno-associated viral vector delivery for reducing hypertension. Hypertension 1997; 29:177-87. [PMID: 9039099 DOI: 10.1161/01.hyp.29.1.177] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Antisense oligodeoxynucleotides have been designed to inhibit the production of specific proteins. In models of hypertension, we have targeted the renin-angiotensin system at the level of synthesis (angiotensinogen) and the receptor (AT1 receptor). The design of antisense oligonucleotides requires choosing a site to inhibit mRNA processig or translation. The strategy we use is to make three oligonucleotides of antisense sequences, upstream and downstream from the AUG site and over the AUG site. The oligonucleotides are tested in a screening test. Antisense oligonucleotides to AT1-receptor mRNA and to angiotensinogen mRNA reduce blood pressure in spontaneously hypertensive rats when injected into the brain. They significantly reduce the concentration of the appropriate protein. The oligonucleotides are also effective when administered systemically. The decrease in blood pressure with antisense oligonucleotides delivered in blood or brain lasts 3 to 7 days. To prolong the action, direct injection of naked DNA and injection of DNA in liposome carriers have been tested. Viral vectors have been developed to deliver antisense DNA. The viral vectors available include retroviruses and adenovirus, but the adeno-associated virus (AAV) vector is the vector of choice for ultimate use in gene therapy. It offers safety because it is nonpathogenic, has longevity because it integrates into the genome, and has sufficient carrying capacity to carry up to 4.5 kb antisense or gene in a recombinant AAV. Using rAAV-antisense to AT1 mRNA, there is efficient transfection into cells and an inhibition of AT1 receptor number. In in vivo tests, rAAV-AS AT1-receptor when injected into the brains of SHR reduces blood pressure for more than 2 months. In young rats (3 weeks old), rAAV-AS AT1-receptor decreases blood pressure and slows the development of hypertension. While further experiments need to be done on dose-response relationships and on the cellular mechanisms of these effects, the results show the feasibility of AAV as a vector for antisense inhibition, which may ultimately be used in gene therapy for hypertension.
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Affiliation(s)
- M I Phillips
- Department of Physiology, College of Medicine, University of Florida, Gainesville, USA.
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477
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Siemering KR, Golbik R, Sever R, Haseloff J. Mutations that suppress the thermosensitivity of green fluorescent protein. Curr Biol 1996; 6:1653-63. [PMID: 8994830 DOI: 10.1016/s0960-9822(02)70789-6] [Citation(s) in RCA: 347] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
BACKGROUND The green fluorescent protein (GFP) of the jellyfish Aequorea victoria has recently attracted great interest as the first example of a cloned reporter protein that is intrinsically fluorescent. Although successful in some organisms, heterologous expression of GFP has not always been straight forward. In particular, expression of GFP in cells that require incubation temperatures around 37 degrees C has been problematic. RESULTS We have carried out a screen for mutant forms of GFP that fluoresce more intensely than the wild-type protein when expressed in E. coli at 37 degrees C. We have characterized a bright mutant (GFPA) with reduced sensitivity to temperature in both bacteria and yeast, and have shown that the amino acids substituted in GFPA act by preventing temperature-dependent misfolding of the GFP apoprotein. We have shown that the excitation and emission spectra of GFPA can be manipulated by site-directed mutagenesis without disturbing its improved folding characteristics, and have produced a thermostable folding mutant (GFP5) that can be efficiently excited using either long-wavelength ultraviolet or blue light. Expression of GFP5 results in greatly improved levels of fluorescence in both microbial and mammalian cells cultured at 37 degrees C. CONCLUSIONS The thermotolerant mutants of GFP greatly improve the sensitivity of the protein as a visible reporter molecule in bacterial, yeast and mammalian cells. The fluorescence spectra of these mutants can be manipulated by further mutagenesis without deleteriously affecting their improved folding characteristics, so it may be possible to engineer a range of spectral variants with improved tolerance to temperature. Such a range of sensitive reporter proteins will greatly improve the prospects for GFP-based applications in cells that require relatively high incubation temperatures.
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478
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Phillips K, Gentry T, McCowage G, Gilboa E, Smith C. Cell-surface markers for assessing gene transfer into human hematopoietic cells. Nat Med 1996; 2:1154-6. [PMID: 8837618 DOI: 10.1038/nm1096-1154] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- K Phillips
- Department of Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA
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479
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Levy JP, Muldoon RR, Zolotukhin S, Link CJ. Retroviral transfer and expression of a humanized, red-shifted green fluorescent protein gene into human tumor cells. Nat Biotechnol 1996; 14:610-4. [PMID: 9630952 DOI: 10.1038/nbt0596-610] [Citation(s) in RCA: 73] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Over two-thirds of the current gene therapy protocols use retroviral gene transfer systems. We have developed an efficient retroviral-based method that allows rapid identification of gene transfer in living mammalian cells. Cells were generated containing a gene for an improved (humanized, red-shifted) version of the Aequorea victoria green fluorescent protein (hRGFP) from a retroviral vector. The hRGFP gene was used to produce an amphotropic vector producer cell line that demonstrated vibrant green fluorescence after excitation with blue light. A375 melanoma cells transduced with the retroviral vector demonstrated stable green fluorescence. Both PA317 murine fibroblasts and A375 human cell lines containing the vector were easily detected by FACS analysis. These vectors represent a substantial improvement over currently available gene transfer marking systems. Bright, long-term expression of the hRGFP gene in living eukaryotic cells will advance the study of gene transfer, gene expression, and gene product function in vitro and in vivo particularly for human gene therapy applications.
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Affiliation(s)
- J P Levy
- Laboratory of Molecular Oncology, Central Iowa Health Systems, Des Moines 50309, USA
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480
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Shibanuma M, Kuroki T, Nose K. Isolation of a gene encoding a putative leucine zipper structure that is induced by transforming growth factor beta 1 and other growth factors. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(19)50006-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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