Many methods have been developed for more efficient gene delivery and expression in human cells. A number of studies have been performed in achieving successful gene delivery and expression conditions. We investigated differential gene expression patterns after delivery adenoviral vector containing green fluorescent protein(GFP) gene into human cancer cell lines. We constructed recombinant adenoviral Ad-CMV-GFP containing CMV promoter and GFP gene. The efficiency of gene expression was assessed by observation GFP expressing cells using fluorescent microscopy after transfer of Ad-CMV-GFP in concentrations of 0.1μl. 1μl. 10μl. At first, we evaluated expression patterns of gene in several human cancer cell lines, gastric adenocarcinoma cell line AGS was showed high level of GFP expression compared with colorectal adenocarcinoma cell line HT-29. After transfer 0.1μl of Ad-CMV-GFP in AGS, we could found that GFP expression cells were observed in next day and highly increased 2 days. While, small number of GFP expressing cells were examined in HT-29 and SNU-C4. Therefore, these data showed that AGS was expressed the highest level of GFP and almost AGS cells seems to express GFP in concentration of 1μl of Ad-CMV-GFP. GFP expression pattern in HT-29 reveal that expression was low in next day after gene transfer but significantly increase expression level in 2 days. In case of SNU-C4, GFP expression increased with increasing concentration of Ad-CMV-GFP and t ransfer times. For examine effects of transfer times in small amount gene, we transfer in concentration of 0.1μl Ad-CMV-GFP and detected GFP expression patterns after 2 days or 4 days. As a result, expression level of GFP in AGS was increase about 2 fold after 4 days compared with 2 days, but any difference of GFP expression levels were not showed in HT-29 and SNU-C4. Our study suggested that adenovirus was very efficient gene transfer vector for gene expression in human cancer cell lines. In addition to, we also demonstrated that gene expression patterns was dependent on each human cell lines. Therefore, further studies will be needed to confirm the optimum conditions for efficient gene delivery and expression in each target cell lines with consideration to cellular properties.

Recent studies on nuclear transfer and induced pluripotent stem cells have demonstrated that differentiated somatic cells can be returned to the undifferentiated state by reversing their developmental process. These epigenetically reprogrammed somatic cells may again be differentiated into various cell types, and used for cell replacement therapies through autologous transplantation to treat many degenerative diseases. To date, however, reprogramming of somatic cells into undifferentiated cells has been extremely inefficient. Hence, reliable markers to identify the event of reprogramming would assist effective selection of reprogrammed cells. In this study, a transgene construct encoding enhanced green fluorescent protein (EGFP) under the regulation of human Oct4 promoter was developed as a reporter for the reprogramming of somatic cells. Microinjection of the transgene construct into pronuclei of fertilized mouse eggs resulted in the emission of green fluorescence, suggesting that the undifferentiated cytoplasmic environment provided by fertilized eggs induces the expression of EGFP. Next, the transgene construct was introduced into human embryonic fibroblasts, and the nuclei from these cells were transferred into enucleated porcine oocytes. Along with their in vitro development, nuclear transfer embryos emitted green fluorescence, suggesting the reprogramming of donor nuclei in nuclear transfer embryos. The results of the present study demonstrate that expression of the transgene under the regulation of human Oct4 promoter coincides with epigenetic reprogramming, and may be used as a convenient marker that non-invasively reflects reprogramming of somatic cells.

The principal objective of this study was to clone transgenic embryos in order to improve the efficiency of transgenic animal production by the combination of microinjection and nuclear transplantation techniques. Mature female New Zealand White rabbits were superovulated by eCG and hCG treatments, fllowed by natural mating. Zygotes were collected from the oviducts at 18∼22 h after hCG injection by flushing with D-PBS containing 5% fetal calf serum(FCS). Two to three picoliters of green fluorescent protein(GFP) gene wa microinjected into male pronucleus. The foreign gene-injected zygotes were cultured in TCM-199 or RD medium containing 10% FCS with a monolayer of rabbit oviductal epithelial cells in a 5% CO2 incubator. The morulae expressing GFP gene were selected and their blastomeres were separated for the use of nuclear donor. Following nuclear transplantation of fluorescence-positive morula stage blastomeres, 13 (21.3%) out of 61 fused oocytes developed to blastocyst stage and all of the cloned blastocysts expressed GFP. The results indicate that the screening of transgene in rabbit embryos by GFP detection could be a promisible method for the preselection of transgenic embryos. Also the cloning of preselected transgenic embryos by nuclear transplantatin could be efficiently applied to the multiple production of transgenic animals.

The efficiency of transgenic livestock production could be improved by early screening of transgene-integration and sexing of embryos at preimplantational stages before trasferring them into recipients. We examined the effciency of multiplex PCR analysis for the simultaneous confirmation of the trasgene and sex during the preimplantational development of bovine embryos and the possibility of green fluorescent protein(GFP) gene as a non-invasive marker for the early screening of transgenic embryos. The GFP gene was microinjected into the male pronuclei of bovine zygotes produced in vitro. The injected zygotes were co-cultured in TCM-199 containing 10% FCS with boving oviductal epithelial cells in a 5% CO2 incubator. Seventeen(13.0%) out of 136 gene-injected bovine zygotes developed by multiplex PCR analysis and the expression of GFP was detected by observing green fluorescence in embryos under a fluorescent microscope. Eight(67%) of 12 embryos at 2-cell to blastocyst stage were positive in the PCR analysis, but only two(11.8%) of 17 blastocysts expressed the GFP gene. Their sex was determined as 7 female and 5 male embryos by the PCR analysis. The results indicate that the screening of GFP gene and sex in bovine embryos by PCR analysis and fluorescence detection could be a promisible method for the preselection of transgenic embryos.

Autographa californica 핵다각체병 바이러스(AcNPV)의 다각체 단백질과 초록색 형광 단백질의 융합단백질의 특성을 분석하였다. 초록색 형광 단백질 유전자는 AcNPV의 완전한 다각체 단백질 유전자의 앞쪽과 뒤쪽에 융합하여 다각체 단백질 유전자의 프로모터 조절하에 도입하였다. 이렇게 작성된 재조합 바이러스를 각각 Ac-GFPPOL 또는 Ac-POLGFP이라고 명명하였다. 이들 재조합 바이러스에 의해 감염된 곤충세포주에서는 56kDa의 융합단백질이 발현되었다. 한편, 흥미롭게도 재조합 바이러스 Ac-POLGFP에 의해 감염된 세포주에서는 초록색 형광이 핵내에서만 다각체 유사 granular particle 형태로 관찰되었다. 반면에 Ac-GFPPOP에 의해 감염된 세포도주에서는 대부분 핵내에 존재하였지만, 세포질과 핵 모두에서 초록색 형광을 관찰할 수 있었다. 그러나 발현된 융합단백질은 분명히 다각체단백질을 포함하고 있음에도 다각체는 형성하지 않았다. 이러한 결과들은 융합단백질에서 다각체단백질의 위치와 관련이 있는 것으로 보여진다.

The efficiency of transgenic livestock animal production may be improved by early selection of transgenci preimplantation embryos. To examine the possibility of GFP gene as a non-invasive marker for the early screening of transgenic embryo, the GFP gene was microinjected into rabbit zygotes and the later stages of preimplantation embryos were examined for the expression of GFP. The presence of injected DNA was detected by PCR analysis and the expression of GFP was detected by observing green fluorescence in embryos under a fluorescent microscope. Out of 108 GFP gene-injected rabbit zygotes, seventy three(67.6%) were fluorescence-positive. When 11 fluroresecence-positive blastocysts were analyzed for the presence of GFP gene by PCR, 6(54.5%) were positive, and all of the 8 flrouescence-negative blastocysts were also negative by PCR. The results indicate that the screening of transgene in rabbit embryos by PCR analysis and GFP detection could be a promising method for the preselection of transgenic embryos.