• Journal of Microbiology and Biotechnology
• /
• 제24권1호
• /
• pp.70-79
• /
• 2014

In an attempt to develop a variety of expression vector systems for Corynebacterium glutamicum, six types of promoters, including $P_{tac}$, $P_{sod}$, $P_{sod}$ with a conserved Shine-Dalgarno (SD) sequence from C. glutamicum, $P_{ilvC}$, $P_{ilvC}$ with a conserved SD-1 ($P_{ilvC-M1}$), and $P_{ilvC}$ with a conserved SD-2 ($P_{ilvC-M2}$), were cloned into a modified shuttle vector, pCXM48. According to analysis of promoter strength by quantitative reverse transcription PCR, $P_{sod}$ and $P_{sod-M}$ were superior to tac and ilvC promoters in terms of transcription activity in C. glutamicum. All of the promoters have promoter activities in Escherichia coli, and $P_{sod-M}$ displayed the highest level of transcriptional activity. The protein expression in constructed vectors was evaluated by measuring the fluorescence of green fluorescent protein (GFP) and SDS-PAGE. C. glutamicum harboring plasmids showed GFP fluorescence with an order of activity of $P_{ilvC}$ > $P_{ilvC-M1}$ > $P_{sod}$ > $P_{ilvC-M2}$ > $P_{sod-M}$, whereas all plasmids except pCSP30 with $P_{sod}$ displayed fluorescence activities in E. coli. Of them, the strongest level of GFP was observed in E. coli with $P_{sod-M}$, and this seems to be due to the introduction of the conserved SD sequence in the translational initiation region. These results demonstrate that the expression vectors work well in both C. glutamicum and E. coli for the expression of target proteins. In addition, the vector systems harboring various promoters with different strengths, conserved SD sequences, and multiple cloning sites will provide a comfortable method for cloning and gene expression, and consequently contribute to the metabolic engineering of C. glutamicum.

• 한국해양바이오학회지
• /
• 제5권4호
• /
• pp.26-32
• /
• 2011

Green fluorescent protein (GFP), a very important biological agent that involves shifting the color of bioluminescence from blue to green in luminous coelenterates and to increase the quantum yield of light emission. GFP discovered in medusa, Aequorea victoria is a key factor of various biotechnological and cell biological applications. Beside these applications, GFP of A. victoria is generally stable, which does not require co-factors for activity and can be functionally expressed in different bacterial species. This property of GFPs from A. victoria permits them to be a unique tool to monitor gene expression and protein localization in different organisms. The present review brings out the past milestones and future perspectives on GFPs, with an elaborative reviewing on its applications.

• 한국동물번식학회:학술대회논문집
• /
• 한국동물번식학회 2004년도 춘계학술발표대회
• /
• pp.188-188
• /
• 2004

근래에 많은 형질전환 실험동물이 생산되어 인간을 대체하여 전임상실험에 사용되고 있으며, 그 요구는 점차 증가되고 있다. 그러나 지금까지 생산된 것은 소형 실험동물에 국한되고 있어, 사람과의 그 크기와 기능에 거리가 있었던 것이 사실이다. 본 실험은 중형 실험동물이자 사람과 여러 기관 및 조직이 유사하다고 알려진 돼지로부터 난자를 채취하여 난자의 핵을 GFP가 발현된 세포의 핵으로 치환하여 태어난 산자를 재복제하여 생산된 돼지 신생자를 이용하여 각 기관 및 조직에서 GFP의 발현을 RT-PCR, Northern blot 및 immunocytochemistry 방법으로 분석하였다. (중략)

• 한국발생생물학회지:발생과생식
• /
• 제17권4호
• /
• pp.379-387
• /
• 2013

Embryonic stem (ES) cells can self-renew and differentiate to various cells depending on the culture condition. Although ES cells are a good model for cell type specification and can be useful for application in clinics in the future, studies on ES cells have many experimental restraints including low transfection efficiency and transgene expression. Here, we observed that transgene expression after transfection was enhanced by treatment with histone deacetylse (HDAC) inhibitors such as trichostatin A, sodium butyrate, and valproic acid. Transfection was performed using conventional transfection reagents with a retroviral vector encoding GFP under the control of CMV promoter as a reporter. Treatment of ES cells with HDAC inhibitors after transfection increased population of GFP positive cells up to 180% compared with untreated control. ES cells showed normal expression of stem cell markers after treatment with HDAC inhibitors. Transgene expression was further enhanced by modifying transfection procedure. GFP positive cells selected after transfection were proved to have the stem cell properties. Our improved protocol for enhanced gene delivery and expression in mouse ES cells without hampering ES cell properties will be useful for study and application of ES cells.

• 한국수정란이식학회:학술대회논문집
• /
• 한국수정란이식학회 2002년도 국제심포지엄
• /
• pp.75-75
• /
• 2002

The present study was conducted for the production of transgenic cloned cows by somatic cell nuclear transfer (SCNT) that secrete human prourokinase into milk. To establish an efficient production system for bovine transgenic SCNT embryos, the offset was examined of various conditions of donor cells including cell type, size, and passage number on the developmental competence of transgenic SCNT embryos. An expression plasmid far human prourokinase (pbeta-ProU) was constructed by inserting a bovine beta-casein promoter, a green fluorescent protein (GFP) marker gene, and a human prourokinase target gene into a pcDNA3 plasmid. Three types of bovine somatic cells including two adult cells (cumulus cells and ear fibroblasts) and fetal fibroblasts were prepared and transfected using a lipid-meidated method. In Experiment 1, developmental competence and rates of GFP expression in bovine transgenic SCNT embryos reconstructed with cumulus cells were significantly higher than those from fetal and ear fibroblasts. In Experiment 2, the effect of cellular senescence in early (2 to 4) and late (8 to 12) passages was investigated. No significant differences in the development of transgenic SCNT embryos were observed. In Experient 3, different sizes of GFP-expressing transfected cumulus cells [large (>30 ${\mu}{\textrm}{m}$) or small cell (<30 ${\mu}{\textrm}{m}$)] were used for SCNT. A significant improvement in embryo development and GFP expression was observed when small cumulus cells were used for SCNT. Taken together, these results demonstrate that (1) adult somatic cells could serve as donor cells in transgenic SCNT embryo production and cumulus cells with small size at early passage were the optimal cell type, and (2) transgenic SCNT embryos derived from adult somatic cells have embryonic development potential.

• 한국발생생물학회:학술대회논문집
• /
• 한국발생생물학회 1998년도 제4차 학술발표대회 및 정기총회
• /
• pp.59-60
• /
• 1998

A DNA construct containing rat T $\alpha$ 1 $\alpha$ -tuulin gene 5'-flanking sequence and GFP reporer gene was microinjected into 1-cell loach embryos. Neuron-specific FGP expression was observed in developing loach embryos and early stage fry. The results demonstrated that rat T $\alpha$ 1 $\alpha$ -tubulin gene promoter may be sufficient to specify gene expression to neurons in loach embryos. Thus, the use of GFP reporter controlled by T $\alpha$ 1 $\alpha$ -tubulin gene promoter may facilitate visualization of the dynamic processes of neural tissue development.

• 한국수정란이식학회지
• /
• 제30권3호
• /
• pp.225-228
• /
• 2015

Understanding the behavior of transgenes introduced into oocyte or embryos is essential for evaluating the methodologies for transgenic animal production. To date, many studies have reported the production of transgenic pig embryos with, however, low efficiency in environment of blastocyst production. The aim of present study was to determine the expression and duration of transgene transferred by intracytoplasmic sperm injection-mediated gene transfer (ICSI-MGT). Embryos obtained from the ICSI-MGT procedure were analysed for the expression of GFP and then for the transmission of the transgene. Briefly, fresh spermatozoa were bound to exogenous DNA after treatment by Triton X-100 and Lipofectin. When ICSI-MGT was performed using sperm heads with tails removed, the yield of blastocyst (25.3%), treated with Lipofectin (18.8%) and Triton X-100 (19.2%) were observed. Treatments of Lipofectin or Triton X-100 did not further improve the rates of blastocysts. Moreover, the apoptosis rates of embryos were obtained from the control and LIpofectin groups (8.7%, 9.7%, respectively), but were significantly higher in the Triton X-100 group (13.0%). Our results demonstrated that ICSI-MGT caused minimal damage to oocytes that could develop to full term. Moreover, the embryos derived by ICSI-MGT have shown prolonged exogenous DNA expression during preimplantation stage in vivo. However, more efforts will be required to improve the procedures of both sperm treatments cause of high frequency of mosaicisms.

• 한국생물공학회:학술대회논문집
• /
• 한국생물공학회 2000년도 추계학술발표대회 및 bio-venture fair
• /
• pp.208-211
• /
• 2000

본 연구를 통해 환경 유해성을 평가하기 위한 동물세포를 개발했고 이를 이용한 모니터링 방법 연구와 다양한 독성 물질에 대한 반응성을 확인했다. 개발된 독성 모니터링 동물세포(KFC-A10)는 각 독성 물질에 따라 빛의 발현 양이 증가하는 성향을 가지므로 이번 실험에서 사용된 MMC, BPA, ${\gamma}-ray$에 농도 의존적으로 빛의 양이 증가함을 관찰할 수 있었다. 특히 BPA의 경우는 환경호르몬으로 알려진 바 그 estrogenic 효과를 관찰할 수 있었다.

• 한국가금학회지
• /
• 제31권4호
• /
• pp.293-298
• /
• 2004

본 연구는 기존의 형질전환 닭 생산방법 중의 하나인 1세 포기 수정란에 유전자를 직접 주입하는 유전자 미세주입방법을 개선할 목적으로 리포좀과 외래 표지 발현유전자인 GFP를 사용하여 외래유전자의 핵전이 효율성과 주입된 외래 유전자의 발현의 지속성을 닭의 배자에서 검증하고자 시도하였다 외래유전자는 배반엽 단계 혹은 1세포기 수정란의 세포질에 리포좀과 유전자의 혼합물 혹은 오직 유전자만을 미세주입을 하였다. 연구 결과들은 리포좀을 사용한 경우 naked DNA에 비하여 배반엽 단계와 1세포기 수정란 모두에서 효율적으로 외래 유전자를 핵내로 도입할 수 있음을 배양 3과 4일차 닭의 배자에서 GFP발현 양상을 통하여 확인하였다. 또한 주입된 외래 유전자에 의해 만들어진 GFP는 배자에서 일주일 정도 지속적으로 발현됨이 관찰되었다. 리포좀 방법은naked유전자 주입 방법에 비해 1세포기와 배반엽 단계 수정란 모두에서 효율적으로 외래 유전자를 핵내로 이동시키는 능력을 가지나, 주입된 유전자의 염색체 삽입에는 큰 영향을 미치지 않는 것으로 판단된다. 따라서 닭의 수정란에서 리포좀 방법은 외래유전자 도입에 유용한 수단으로 이용되어질 수 있을 것으로 사료된다.

• Reproductive and Developmental Biology
• /
• 제30권2호
• /
• pp.81-85
• /
• 2006

This study was conducted to examine the effect of IRES controlled reporter gene on screening and production of recombinant human erythropoietin (EPO) proteins from cultured CHO cells. The cDNA was cloned for EPO from human liver cDNA Using site-directed mutagenesis, we generated recombinant human EPO (rhEPO) with two additional N-glycosylations (Novel erythropoiesis-stimulating protein: NESP). Wild type hEPO and NESP were cloned into expression vectors with GFP reporter gene under regulatory control of CMV promoter and IRES so that the vectors could express both rhEPO and GFP. The expression vectors were transfected to cultured CHO-K1 cells. Under microscopy, expression of GFP was visible. Using supernatant of the culture, ELISA assay, immunocytochemistry and in vitro assay using EPO dependant cell line were performed to estimate biological activity to compare the production characteristics (secretion levels, etc.) between rhEPO and NESP. The activity of NESP protein, obtained by mutagenesis, was described and compared with its rhEPO counterpart produced under same conditions. Although NESP had less secretion level in CHO cell line, the biological activity of NESP was greater than that of rhEPO. These results are consistent with previous researches. We also demonstrated that rhEPO and GFP proteins expressed simultaneously from transfected CHO cell line. Therefore we conclude that use of GFP reporter gene under IRES control could be used to screen and produce rhEPO in cultured CHO cells.