• Title, Summary, Keyword: stable transfection

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Efficient transgene expression system using a cumate-inducible promoter and Cre-loxP recombination in avian cells

  • Park, Tae Sub;Kim, Si Won;Lee, Jeong Hyo
    • Asian-Australasian Journal of Animal Sciences
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    • v.30 no.6
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    • pp.886-892
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    • 2017
  • Objective: Transgenic technology is widely used for industrial applications and basic research. Systems that allow for genetic modification play a crucial role in biotechnology for a number of purposes, including the functional analysis of specific genes and the production of exogenous proteins. In this study, we examined and verified the cumate-inducible transgene expression system in chicken DF1 and quail QM7 cells, as well as loxP element-mediated transgene recombination using Cre recombinase in DF1 cells. Methods: After stable transfer of the transgene with piggyBac transposon and transposase, transgene expression was induced by an appropriate concentration of cumate. Additionally, we showed that the transgene can be replaced with additional transgenes by co-transfection with the Cre recombinase expression vector. Results: In the cumate-GFP DF1 and QM7 cells, green fluorescent protein (GFP) expression was repressed in the off state in the absence of cumate, and the GFP transgene expression was successfully induced in the presence of cumate. In the cumate-MyoD DF1 cells, MyoD transgene expression was induced by cumate, and the genes controlled by MyoD were upregulated according to the number of days in culture. Additionally, for the translocation experiments, a stable enhanced green fluorescent protein (eGFP)-expressing DF1 cell line transfected with the loxP66-eGFP-loxP71 vector was established, and DsRed-positive and eGFP-negative cells were observed after 14 days of co-transfection with the DsRed transgene and Cre recombinase indicating that the eGFP transgene was excised, and the DsRed transgene was replaced by Cre recombination. Conclusion: Transgene induction or replacement cassette systems in avian cells can be applied in functional genomics studies of specific genes and adapted further for efficient generation of transgenic poultry to modulate target gene expression.

Establishment of an In Vitro TCD (Testosterone Compound Detection) System (테스토스테론 물질 검출을 위한 in vitro TCD 시스템 구축)

  • Lee, Dong-Geun;Jo, Jung-Kwon;Lee, Sang-Hyeon
    • Journal of Life Science
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    • v.29 no.10
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    • pp.1159-1163
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    • 2019
  • Although there is a growing interest in male menopause, a phenomenon associated with male hormone depletion, current kits using antibodies to quantify male hormones are expensive. In this study, we constructed an in vitro system for verifying the activity or concentration of male steroid hormones using a transcriptional activity test. A reporter plasmid, pGL2-Neo-ARE-AdE1BTATA, which reacts to testosterone, was constructed. In this plasmid, the ARE-AdE1bTATA sequences can be bounded by the testosterone - androgen receptor complex to express luciferase as a reporter. Then, a stable transfection was performed on the human prostate cancer cell line, LNcap-LN3. The constructed LNcap-LN3/pGL2-Neo-ARE-AdE1BTATA testosterone compound detection (TCD) system showed quantitatively proportional luciferase activities to concentrations of $10^{-13}$ to $10^{-8}M$ of standard testosterone. The established in vitro TCD system will contribute to the development of materials for health/functional foods and drugs as it will be possible to search en masse for testosterone-like or testosterone-inhibiting substances derived from natural materials.

EBV-Based Plasmid Encoding HSV-TK for Cytocidal Gene Therapy (HSV-TK 유전자를 암호화하는 EBV 유래 플라스미드를 이용한 유전자 치료)

  • Oh, Sang-Taek;Min, Kyoung-Ah;Kim, Chong-Kook;Lee, Suk-Kyeong
    • Journal of Pharmaceutical Investigation
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    • v.33 no.4
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    • pp.267-272
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    • 2003
  • Herpes simplex virus (HSV) thymidine kinase (TK) has been widely used for suicidal gene therapy in combination with nucleoside analogs such as ganciclovir (GCV). The use of HSV-TK is limited due to the side effect of GCV at high concentrations. Previous studies showed that stable transfectants of mutant HSV-TK with enhanced affinity to GCV were killed at lower GCV concentrations. In this study, we tested whether mutant HSV-TK can provide enhanced suicidal effect when transiently transfected with Epstein-Barr virus (EBV)-based plasmid. EBV-based plasmid which contains OriP and EBNA-1 sequence is well known for a stable episomal maintenance in human cells. Optimal transfection condition was assessed for SNU-638 gastric cancer cell line using polyetylnimine (PEI). Maximum transfection efficiency was achieved when DNA:PEI was 1:3 (w/v). Cytotoxicities of mutant and wild type HSV-TK were compared before and after partially selecting transfected cells. The cells were sensitive to $100\;{\mu}g/ml$ hygromycin. Following GCV treatment, more cells were killed after hygromycin selection than before selection. The mutant HSV-TK showed enhanced cytotoxicity compared with the wild type HSV-TK. Our results suggest that the EBV-based plasmid encoding mutant HSV-TK may be useful to treat the diseases caused by uncontrolled cell proliferation such as cancer and rheumatoid arthritis.

요소회로 효소 유전자로 형질전환 된 Chinese Hamster Ovary 세포의 암모니아 제거능력과 세포성장률

  • Kim, Hong-Jin;Jeong, Myeong-Il;Jang, Yun-Jeong;Im, Mi-Hui;Kim, Ik-Hwan;Kim, Ik-Yeong
    • 한국생물공학회:학술대회논문집
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    • pp.66-69
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    • 2001
  • Previously we developed a CHO cell line (CHO-OTC1-A19) expressing the first two enzymes of urea cycle. This cell line showed higher ammonia removal activity and faster growth rate than the vector controlled CHO cells (CHO-neo-5). The purpose of this study was to develop a cell line with higher ammonia removal activity than the cell line developed previously. To accomplish this, we constructed stable CHO cell lines expressing the first three, the first four, or all five enzymes of urea cycle by the stable transfection method. We finally selected CHO-AL-19 cell line expressing the first three, the first four enzymes of the cycle with higher ammonia activity than CHO-OTC1-A19 and CHO-n대-5 cell lines: 40% and 15% higher than those of CHO-neo-5 and CHO-OTC1-A19 cell lines 72 hour after culture started, respectively. It also showed 44% and 10% higher cell viability than CHO-neo-5 and CHO- OTC1-A19 cell lines at higher cell density. In addition, CHO-AL-19 cells showed 45%-60% and about 20% lower ammonia concentration per cell than those of CHO-neo-% and CHO-OTC1-A19 cell lines, respectively. These results indicate that CHO-AL-19 could be used in the production of human therapeutic proteins with higher efficiency.

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Enhancement of Erythropoietin Production from Chinese Hamster Ovary(CHO) Cells by Introduction of the Urea Cycle Enzymes, Carbamoyl Phosphate Synthetase I and Ornithine Transcarbamylase

  • Kim, Na-Young;Lee, Yun-Jeong;Kim, Hyung-Jin;Choi, Jung-Ho;Kim, Jung-Kwon;Chang, Kern-Hee;Kim, Jung-Hoe;Kim, Hong-Jin
    • Journal of Microbiology and Biotechnology
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    • v.14 no.4
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    • pp.844-851
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    • 2004
  • Efficient mammalian erythropoietin (EPO)-expression systems are required for therapeutic applications. The accumulation of ammonia is a major problem in the production of recombinant proteins in cultured animal cells. To counter this problem we introduced the first two genes of the urea cycle, carbamoyl phosphate synthetase (CPSI) and ornithine transcarbamylase (OTC), into IBE Chinese Hamster Ovary (CHO) cells by stable transfection. The resulting cell line, CO5, had a higher growth rate and accumulated less ammonia per cell than the parental cell line, IBE. In addition, it produced 2 times more EPO than the parent, and the purified EPO contained a higher proportion of acidic isoforms with approximately 15% more sialic acid.

Characterization of Erythropoietin Producing Cell Lines after Introduction of Urea Cycle Enzymes, Carbamoly Phosphate Synthetase and Ornithine Transcarbamoylase

  • Lee, Yun-Jeong;Kim, Na-Young;Kim, Hyung-Jin;Park, Jung-Ho;Kim, Jung-Kwon;Hee, Chang-Kern;Kim, Jung-Hoe;Kim, Hong-Jin
    • Proceedings of the PSK Conference
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    • pp.170.3-170
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    • 2003
  • An efficient Erythropoietin (EPO)-expression system in mammalian cells is required for massive production for therapeutic use. Ammonium ion is a major problem in the production of valuable recombinant proteins in cultured animal cells. Therefore, it is of importance to devise a system by which a high productivity of human therapeutic recombinant protein can be maintained or enhanced under low ammonium concentration. To reduce the ammonium ion accumulated in EPO producing Chinese Hamster Ovary (CHO) ceels, IBE, we introduced the first two genes of the urea cycle, carbamoyl phosphate synthetase (CPSI) and arnithine transcarbamoylase (OTC), into IBE using a stable transfection method. (omitted)

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EphA Receptors Form a Complex with Caspase-8 to Induce Apoptotic Cell Death

  • Lee, Haeryung;Park, Sunjung;Kang, Young-Sook;Park, Soochul
    • Molecules and Cells
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    • v.38 no.4
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    • pp.349-355
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    • 2015
  • EphA7 has been implicated in the regulation of apoptotic cell death in neural epithelial cells. In this report, we provide evidence that EphA7 interacts with caspase-8 to induce apoptotic cell signaling. First, a pull-down assay using biotinylated ephrinA5-Fc showed that EphA7 co-precipitated with wild type caspase-8 or catalytically inactive caspase-8 mutant. Second, co-transfection of EphA7 with caspase-8 significantly increased the number of cleaved caspase-3 positive apoptotic cells under an experimental condition where transfection of EphA7 or caspase-8 alone did not affect cell viability or apoptosis. EphA4 also had a causative role in inducing apoptotic cell death with caspase-8, whereas EphA8 did not. Third, caspase-8 catalytic activity was essential for the apoptotic signaling cascade, whereas tyrosine kinase activity of the EphA4 receptor was not. Interestingly, we found that kinase-inactive EphA4 was well co-localized at the plasma membrane with catalytically inactive caspase-8, suggesting that an interaction between these mutant proteins was more stable. Finally, we observed that the extracellular region of the EphA7 receptor was critical for interacting with caspase-8, whereas the cytoplasmic region of EphA7 was not. Therefore, we propose that Eph receptors physically associate with a transmembrane protein to form an apoptotic signaling complex and that this unidentified receptor-like protein acts as a biochemical linker between the Eph receptor and caspase-8.

Induction of Apoptosis in Glioma Cells and Upregulation of Fas Expression Using the Human Interferon-β Gene

  • Guo, Yan;Wang, Gan;Gao, Wen-Wei;Cheng, Shi-Wen;Wang, Ren;Ju, Shi-Ming;Cao, He-Li;Tian, Heng-Li
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2837-2840
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    • 2012
  • We investigated whether IFN-${\beta}$ inhibits the growth of human malignant glioma and induces glioma cell apoptosis using the human IFN-${\beta}$ gene transfected into glioma cells. A eukaryonic expression vector ($pSV2IFN{\beta}$) for IFN-${\beta}$ was transfected into the glioma cell line SHG44 using liposome transfection. Stable transfection and IFN-${\beta}$ expression were confirmed using an enzyme-linked immunosorbent assay (ELISA). Cell apoptosis was also assessed by Hoechst staining and electron microscopy. In vivo experiments were used to establish a SHG44 glioma model in nude mice. Liposomes containing the human IFN-${\beta}$ gene were injected into the SHG44 glioma of nude mice to observe glioma growth and calculate tumor size. Fas expression was evaluated using immunohistochemistry. The IFN-${\beta}$ gene was successfully transfected and expressed in the SHG44 glioma cells in vitro. A significant difference in the number of apoptotic cells was observed between transfected and non-transfected cells. Glioma growth in nude mice was inhibited in vivo, with significant induction of apoptosis. Fas expression was also elevated. The IFN-${\beta}$ gene induces apoptosis in glioma cells, possibly through upregulation of Fas. The IFN-${\beta}$ gene modulation in the Fas pathway and apoptosis in glioma cells may be important for the treatment of gliomas.

Combination of Epstein-Barr Virus-Based Plasmid and Nonviral Polymeric Vectors for Enhanced and Prolonged Gene Expression

  • Choi, Hye;Park, Key Sun;Bae, Seon Joo;Song, Su Jeong;Kim, Kyoon Eon;Park, Jong-Sang;Choi, Joon Sig
    • Bulletin of the Korean Chemical Society
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    • v.33 no.11
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    • pp.3676-3680
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    • 2012
  • An Epstein-Barr virus (EBV)-based plasmid contains the EBV nuclear antigen 1 (EBNA1) gene and EBV replication origin (oriP) sequence. Since EBNA1 (the only EBV-encoded protein) is combined with oriP, it is replicated simultaneously with chromosomal DNA in human, primate, and canine cells and is faithfully segregated at a stable copy number upon cell division. Consequently, it can be used to stably express gene inserts over a prolonged time in target cells. We have previously shown that the polyamidoamine (PAMAM) dendrimer can be surface-modified with L-arginine. Arginine is present at a high frequency in the transactivator of transcription (Tat) sequences of human immunodeficiency virus (HIV). It presents high membrane permeability and permits effective transfer of DNA inside the cells. In this study, we constructed two kinds of recombinant DNA by inserting the luciferase gene and enhanced green fluorescence protein (eGFP) gene as reporter genes into the pCEP4 plasmid vector. We measured dynamic light scattering (DLS) and zeta potential after preparing PAMAM-based cationic polymer/EBV-based plasmid complexes. We performed transfection of HEK 293 cell lines with the polyplexes, and monitored luciferase activity and green fluorescence protein (GFP) expression. Our results show that PAMAM-based cationic polymer/EBV plasmid complexes provide enhanced and sustained gene expression.

Liposome-mediated in Vivo Delivery of Transgene by Vein Injection

  • Choi, Seung-Kyu;Choi, Sung-Sik;Hwang, Chang-Nam;Lee, Sang-Ho
    • Proceedings of the KSAR Conference
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    • pp.98-98
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    • 2003
  • Direct gene transfer to mammalian tissues has significant potential for gene therapy and transgenesis. Liposome-mediated in vivo transfection has begun to gain attention as an alternative to viral vectors, and may also be a good mode of transfection in gene transfer. Interestingly, polymerized cationic liposomes are reported to be very stable in the bloods and efficient for in vivo gene transfer. To examine a possible gene delivery in vivo, we investigated the efficacy and safety of the liposome-mediated gene transfer using vein injection in chick or mouse as model animals. The number of injected pGFP-LacZ using either a commercial or home-made liposomes was 8 and 19 at 16 and 7 day of hatch, respectively. One of injected chick of each experiments was analyzed and the rest is being bred. In mouse, 4/22 showed expression of pGFP-LacZ but 8/22 showed no expression and the remaining animals are also being bred. After injection of liposome/pGFP-LacZ complex into wing vein of 7 or 16 day-old chick, pGFP-LacZ was detected in various tissues isolated from not only young chick but also old chick were turned out to possess. exogenous DNA. Transcripts and proteins of the transgene were also detected by RT-PCR or histochemical analysis, respectively. These results suggest that injected DNA were inserted to genome and produced mRNA and proteins in various tissues and may give an important tools for effective gene delivery in gene therapy or transgenesis.

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