Expression of the Capsid Precursor Protein gene of Foot-and-mouth Disease Virus and Green Fluorescent Protein Gene in BHK-21 Cells Mediated by Retroviral Vector

We have constructed a retroviral vector mediated mammalian cell expression system of the capsid precursor protein of foot-and-mouth disease virus(FMDV).The recombinant retroviral vector pBABEpuro-P1-2A-EGFP was constructed by sequentially inserting capsid precursor protein gene(P1) of FMDV and enhanced green fluorescent protein gene(EGFP) into pBABEpuro.The recombinant retroviral vector and the pVSV-G plasmid were co-transfected into packaging cells(GP2-293) by liposomemediated transduction to produce the pseudovirus.The pseudovirus was used to infect BHK-21 cells and resistant cells were screened with puromycin.Green fluorescent proteins were observed by fluorescence microscopy and expression of the capsid precursor protein gene of FMDV was detected by indirect immunofluorescence.The recombinant retroviral vector pBABEpuro-P1-2A-EGFP was constructed successfully.The capsid precursor protein of FMDV and green fluorescent protein were expressed in BHK-21 cells.The mammalian cell expression system for the capsid precursor protein of FMDV has been constructed successfully,which lays the foundation of development of a FMDV subunit vaccine.

Construction of bicistronic green fluorescent protein labeled pSELECT GFPzeo human bone morphogenetic protein 2 eukaryotic expression vector

Objective To construct green fluorescent protein (GFP)-labeled pSELECT-GFP zeohBMP2 eukaryotic expression vector.Methods The encoding fragment of hBMP2 gene was obtained from a recombinant plasmid pcDNA3.1/CT-hBMP2 by using polymerase

Gene transfer into primary cultures of fetal neural stem cells by a recombinant adenovirus carrying the gene for green fluorescent protein

Objective: To evaluate the transduction efficiency of a recombinant adenovirus carrying the gene for green fluorescent protein (Ad-GFP) into the primary cultures of fetal neural stem cells (NSCs) by the expression of GFP. Methods: The Ad-GFP was constructed by homologous recombination in bacteria with the AdEasy system; NSCs were isolated from rat fetal hippocampus and cultured as neurosphere suspensions. After infection with the recombinant Ad-GFP, NSCs were examined with a fluorescent microscopy and a flow cytometry for their expression of GFP. Results: After the viral infection, flow cytometry analysis revealed that the percentage of GFP-positive cells was as high as 97.05%. The infected NSCs sustained the GFP expression for above 4 weeks. After differentiated into astrocytes or neurons, they continued to express GFP efficiently. Conclusion: We have success- fully constructed a viral vector Ad-GFP that can efficiently infect the primary NSCs. The reporter gene was showed fully and sustained expression in the infected cells as well as their differentiated progenies.

THE ENHANCED GREEN FLUORESCENT PROTEIN AS A MARKER FOR HUMAN TUMOR CELLS LABELLED BY RETROVIRAL TRANSDUCTION

Objective: To investigate the feasibility of marking the human tumor cells with enhanced green fluorescent protein (EGFP) in vitro. Methods: The retroviral vector LGSN encoding EGFP was constructed and three human tumor cell lines were infected with LGSN amphotropic virus. Tumor cell lines that stably express EGFP were selected with G418. The integration and expression of EGFP gene were analyzed by polymerase chain reaction, and flow cytometry (FCM). Results: After gene transfection and ping-pong transduction, amphotropic producer line Am12/LGSN was generated with a stable green fluorescence signal readily detectable by FCM in up to 97% of examined cells. The viral titer in the supernatants was up to 8.2×105CFU/ml. After transduction and selection, G418-resistant leukemia K562, mammary carcinoma MCF-7, and bladder cancer 5637 cells were developed, in which the integration of both EGFP and neomycin resistance gene was confirmed by DNA amplification. In comparison with uninfected cells, FCM analysis revealed EGFP expression in up to 90% (range 85.5%–90.0%) of tumor cells containing LGSN provirus. Conclusion: The retroviral vector LGSN can effectively mark the human tumor cells with a stably EGFP expression which may be in studying tumor growth, metastasis and angiogenesis.

Construction of Rat Calcineurin A α cDNA Recombinant Adenovirus Vector and Its Identification

Rat calcineurin （CAN） A a isoform （Ppp3ca） cDNA recombinant adenovirus vector was constructed in order to explore the effect of CaN on the myocardium apoptosis induced by ischemia-reperfusion injury. Total RNA was isolated from the heart of the adult Wistar rht, and Ppp3ca CDS segment of approximate 1.59 kb size was amplified by reverse transcriptional PCR method. Ppp3ca cDNA segment was cloned into pMD18-T Simple vector for sequencing, and the right clone was named T-Ppp3ca. Ppp3ca cDNA segment obtained from T-Ppp3ca was ligated with pShuttle2-IRES-EGFP to construct a recombinant plasmid pShuttle2-Ppp3ca-IRES-EGFP. Ppp3ca-IRES-EG- FP expression cassette containing CMV, Ppp3ca-IRES-EGFP and SV40 polyA DNA fragment （3.97 kb） obtained from pShuttle2-Ppp3ca-IRES-EGFP was connected with pAdeno-X backbone sequence to construct a recombinant plasmid pAdeno Ppp3ca. After being identified by PCR and enzyme digestion, recombinant plasmid pAdeno-Ppp3ca was packaged in HEK293 cells. Supernatant of adenovirus from HEK293 cells was collected after a visible cytopathic effect （CPE） appeared. The DNA of the recombinant adenovirus was extracted with the standard method. The presence of the recombinant adenovirus was verified by PCR. The results showed that sequencing results verified that the PCR product of Ppp3ca gene was identical to GenBank. Agarose electrophoresis showed the bands of recombined plasmid pAdeno-Ppp3ca and the recombinant adenovirus identified by enzyme digestion and PCR were in the right range corresponding with expectation. It was concluded that the recombinant adenovirus carrying rat calcineurin A a （Ppp3ca） cDNA as well as a report gene-enhancer green fluorescent protein gene was successfully constructed in this experiment.

Expression of Green Fluorescent Protein Gene with Baculovirus Vectorin Insect Cells

The green fluorescence of bioluminescent jellyfish Aequorea victoria is due to the presence of the green fluorescent protein (GFP). To examine whether the GFP gene can be applied as a reporter gene in insect cells, a baculovirus transfer vector containing the neomycin resistance gene (neo) was established. The GFP gene was subcloned into the vector downstream of the polyhedrin gene (ocu) promoter. In the presence of G418, the recombinant virus can be purified. Expression of the GFP gene in the recombinant virus should give rise to synthesis of the GFP with a molecular weight of 30×10 3 dalton, and is observable by the strong green light irradiated by ultraviolet or blue light in viable intact insect cells. The GFP produced in insect cells has typical fluorescent spectra indistinguishable from those of the purified native GFP. The GFP gene as a good reporter gene can be applied to the baculovirus insect cell expression system.

Application of Green Fluorescent Protein Gene (gfp) in the Symbiosis between Mesorhizobium Huakuii and Astragalus Sinicus

Green fluorescent protein (GFP) is a luminescent protein which was first discovered from A equoreavicto-ria[1]. The chromophore of wild type GFP consists of an imidazoione ring formed by cyclization of Ser65, dehydrated Tyr66 and Gly67. GFP can emit 510 nm green fluorescence (Emmax = 510 nm) by 395 nm

Construction of Ad-EGFP-BDNF vector and its expression in neural stem cells

BACKGROUND： Brain-derived neurotrophic factor （BDNF） provides nourishment to injured neurons. Neural stem cells can differentiate into neurons to repair neuronal injury in vivo. It has been hypothesized that continuous secretion of BDNF from neural stem cells could benefit brain injury repair. OBJECTIVE： To transfect BDNF and enhanced green fluorescent protein （EGFP） into neural stem cells with adenovirus vector and to observe expression of BDNF and EGFP in transfected neural stem cells. DESIGN, TIME AND SETTING： Observational, cellular, molecular study was performed at the Biochemistry Laboratory, Tongji University School of Medicine, China from July 2004 to September 2006. MATERIALS： Neural stem cells were provided by the Anatomy and Histoembryology Laboratory of Fudan University Medical School, China. METHODS： BDNF cDNA was extracted by reverse transcription polymerase chain reaction from the rat hippocampus. Following gene cloning and packaging by HEK293.BDNF, the EGFP gene was transfected into cultured neural stem cells with the Ad-EGFP-BDNF vector. BDNF-expressing neural stem cell clones were selected by G418 selection. MAIN OUTCOME MEASURES： EGFP expression and cell morphology were observed by fluorescent microscopy; neural stem cell expressing BDNF mRNA was examined by reverse transcription polymerase chain reaction; BDNF expression was detected by enzyme-linked immunosorbent assay from supematant of infected neural stem cells. RESULTS： High transfection efficiency was obtained using 5×10^8 virus titers to transfect neural stem cells. G418-resistant neural stem cell clones integrated BDNF mRNA fragments. Enzyme-linked immunosorbent assay results showed that BDNF expression in the supernatant increased with increasing culture time and peaked at 72 hours. CONCLUSION： Adenovirus-mediated BDNF and EGFP genes were successfully transfected into neural stem cells and were expressed in neural stem cells for a long period of time.

Retrovirus-mediated transfer of the fusion gene encoding EGFP-BMP_2 in mesenchymal stem cells

Objective To develop retrovirus-mediated transfer of the fusion gene encoding EGFP-BMP_2 in mesenchymal stem cells.Methods Mesenchymal stem cells from New Zealand white rabbits were transduced with retroviral pLEGFP-BMP_2 vector by the optimized retroviral transduction protocol.Fluorescent microscopy's examination was to evaluate the results of the transduction,flow cytometer's analysis was to evaluate the transduction efficiency and the Fluorescence-activated cell sorting method was to sort the transduced cells.Bioactivity test from C_2C_12K_4 cells was to show the expression and bio-activity of the fusion gene.Results Fluorescent microscopy showed the success of the transduction.By flow cytometer's analysis,the mean efficiency of the transduction with EGFP was(42.8±6.1)% SD.Transduced cells were sorted efficiently by the fluorescence-activated cell sorting method and after sorting,almost of those showed the expression of BMP_2.Fluorescently and strongly bioactivity test for C_2C_12K_4 cells demonstrated that fluorescent materials were located the surface of cells and the activity of luciferase increased compared with the control.Analysis of long-term expression showed there was no difference between 2 week-time point and 3 month-time point of culture post-sorting.Conclusion Mesenchymal stem cells can be transduced efficiently by retrovirus-mediated transfer of the fusion gene encoding EGFP-BMP_2,the highly pure transduced cells are obtained by the fluorescence-activated cell sorting technique,the expressed chimeric protein embraced the double bioactivity of EGFP and BMP_2,and moreover,the expression had not attenuated over time.

Fetal vs adult mesenchymal stem cells achieve greater gene expression, but less osteoinduction

AIM: To investigate adenoviral transduction in mesenchymal stem cells(MSCs) and effects on stemness in vitro and function as a cell therapy in vivo.METHODS: Bone marrow-derived adult and fetal MSC were isolated from an equine source and expanded in monolayer tissue culture. Polyethylenimine(PEI)-mediated transfection of pc DNA3-e GFP or adenoviral transduction of green fluorescent protein(GFP) was evaluated in fetal MSCs. Adenoviral-mediated transduction was chosen for subsequent experiments. All experiments were carried out at least in triplicate unless otherwise noted. Outcome assessment was obtained by flow cytometry or immunohystochemistry and included transduction efficiency, cell viability, stemness(i.e., cell proliferation, osteogenic and chondrogenic cell differentiation), and quantification of GFP expression. Fetal and adult MSCs were then transduced with an adenoviral vector containing the gene for the bone morphogenic protein 2(BMP2). In vitro BMP2 expression was assessed by enzyme linked immunosorbent assay. In addition, MSC-mediated gene delivery of BMP2 was evaluated in vivo in an osteoinduction nude mouse quadriceps model. New bone formation was evaluated by microradiography and histology.RESULTS: PEI provided greater transfection and viability in fetal MSCs than other commercial chemical reagents. Adenoviral transduction efficiency was superior to PEI-mediated transfection of GFP in fetal MSCs(81.3% ± 1.3% vs 35.0% ± 1.6%, P < 0.05) and was similar in adult MSCs(78.1% ± 1.9%). Adenoviral transduction provided significantly greater expression of GFP in fetal than adult MSCs(7.4 ± 0.1 vs 4.4 ± 0.3 millions of mean fluorescence intensity units, P < 0.01) as well as significantly greater in vitro BMP2 expression(0.16 pg/cell-day vs 0.10 pg/cell-day, P < 0.01). Fraction of fetal MSC GFP positive cells decreased significantly faster than adult MSCs(1.15% ± 0.05% vs 11.4% ± 2.1% GFP positive at 2 wk post-transduction, P < 0.05). Cell proliferation and osteogenic differentiation in vitrowere not affected by Ad transduction in both fetal and adult MSCs, but fetal MSCs had reduced chondrogenic differentiation in vitro when compared to adult(P < 0.01). Chondrogenic differentiation was also significantly reduced in Ad-GFP transduced cells(P < 0.05). AdBMP2 transduced adult MSCs induced new bone formation in more thighs than Ad-BMP2 transduced fetal MSCs(83% vs 17% of the six treated thighs per group, P < 0.05) and resulted in increased femur midshaft diameter due to greater extent of periosteal new bone(1.57 ± 0.35 mm vs 1.27 ± 0.08 mm, P < 0.05).CONCLUSION: Fetal MSCs may be genetically manipulated ex vivo with adenoviral vectors. Nonetheless, the abbreviated expression of the exogenous gene may limit their applications in vivo.

增强型绿色荧光蛋白逆转录病毒载体的构建和表达

逆转录病毒载体被广泛用作对造血细胞进行基因转移的工具 ,转导方法的改进有赖于应用可快速分析并被高效选择的基因标志。为此 ,我们克隆了增强型绿色荧光蛋白 (EGFP)基因 ,并构建可表达EGFP的逆转录病毒载体LGSN ,通过脂质体转染和交互感染方法建立高滴度的逆转录产病毒细胞 ,用以分析对造血细胞标记EGFP基因的可行性。流式细胞术和荧光显微镜检测发现 ,EGFP病毒转录的GP +envAm12细胞和K5 62细胞均可发出稳定的绿色荧光信号 ,阳性率可分别达 97%和 86% ;聚合酶链反应分析显示LGSN转导细胞内有原病毒的整合。上述结果提示 ,作为新一代选择性标志 ,EGFP是适于研究对造血细胞基因转移与表达的报告基因 。

携带绿色荧光蛋白基因的逆转录病毒载体的构建及其介导的T细胞基因转移研究

为了构建含绿色荧光蛋白(greenfluorescentprotein,GFP)基因的逆转录病毒载体和研究逆转录病毒对T细胞的感染能力,利用亚克隆技术将磷酸甘油酸激酶启动子(phosphoglyceratekinasepromoter,PGK)基因和GFP全长cDNA插入逆转录病毒载体pLXSN,采用磷酸钙沉淀法将重组载体转染PA317包装细胞,G418筛选出抗性克隆,收集滴度最高的病毒上清感染NIH3T3和T细胞,在倒置荧光显微镜下观察GFP表达情况。结果表明;重组逆转录病毒载体转染PA317包装细胞后,可在荧光显微镜下观察到GFP的表达。G418筛选后,含GFP的逆转录病毒可感染原代培养的T细胞。结论:逆转录病毒载体能够快速、稳定地将外源基因转移至T细胞,可作为介导T细胞基因转移的重要工具。

一种重组腺病毒载体产生及操作的新方法

目的 建立一种快速、高效的产生腺病毒的实验方法。方法 将增强型绿色荧光蛋白 (EGFP)装在穿梭质粒 ,线性化后与腺病毒骨架载体一起电穿孔转染大肠杆菌 ,使之同源重组 ,产生病毒基因组质粒。后Pac酶切 ,脂质体介导转入 2 93细胞以包装出病毒。扩增后收获病毒 ,氯化铯密度梯度离心纯化 ,空斑试验测滴度。结果 5 2个大肠杆菌克隆 ,其中有 1个发生同源重组 ,产生腺病毒基因组质粒pAdEGFP ,转染 2 93细胞 ,荧光显微镜下产生绿色荧光。病毒纯化后达 10 11pfu/ml。 结论 大肠杆菌内质粒间同源重组的方法可以高效、简便、快捷地产生重组腺病毒载体 。

逆转录病毒载体介导的口蹄疫病毒衣壳前体基因和绿色荧光蛋白基因在BHK-21细胞中的表达

为建立逆转录病毒载体介导的口蹄疫病毒衣壳前体蛋白哺乳动物细胞表达体系,将口蹄疫病毒(FMDV)衣壳前体基因(P1)和绿色荧光蛋白基因(EGFP)依次插入逆转录病毒载体pBABEpuro构建重组逆转录病毒载体pBABEpuro-P1-2A-EGFP。将重组逆转录病毒载体和pVSV-G质粒载体共转染GP2-293包装细胞,用产生的重组逆转录病毒感染幼仓鼠肾细胞(BHK-21)。荧光显微镜下观察绿色荧光蛋白的表达,用嘌呤霉素筛选抗性细胞,间接免疫荧光方法检测细胞中FMDV衣壳前体蛋白的表达。结果表明,重组逆转录病毒载体pBABEpuro-P1-2A-EGFP构建正确,绿色荧光蛋白和FMDV衣壳前体蛋白在细胞中能稳定表达。FMDV衣壳前体蛋白基因细胞表达体系的成功建立为进一步开展口蹄疫亚单位疫苗的研制奠定了基础。

绿色荧光蛋白在植物病理学研究中的应用

绿色荧光蛋白(green fluorescent protein,GFP)是生命科学研究中的一种重要报告基因,本文在论述GFP的发现、结构和发光原理的基础上,从抗病基因的亚细胞定位、启动子活性分析、病原菌-植物互作研究和基因表达分析等方面讨论GFP在植物病理学研究中的应用。

GFP基因在棉花转化中的应用

以绿色荧光蛋白GFP基因为报道基因，用花粉管通道和农杆菌介导的转化方法将外源基因导入棉花(Gossypium hirsutum L.)，分别获得转化幼胚、幼苗和转化愈伤组织。用手持紫外灯结合显微镜检术能够快速地对转化子进行活体筛选鉴定，比用GUS检测方法有明显的优越性。本研究不但为花粉管通道转化法的可行性提供了新的证据，同时也建立了GFP用于棉花基因工程研究的检测技术体系。

人KLK1和EGFP双顺反子重组腺病毒构建及其在血管平滑肌细胞中的表达

目的:构建携EGFP为报告基因和人组织激肽释放酶1(hKLK1)基因双顺反子的重组腺病毒(Ad-hKLK1-IRES-EGFP),并观察在自发性高血压大鼠(SHR)血管平滑肌细胞(VSMCs)中的表达变化。方法:通过双酶切质粒pBluescritII KS-hKLK1,将hKLK1基因定向克隆至带有IRES-EGFP的腺病毒穿梭质粒pDC316中,构建成重组穿梭质粒,将其与腺病毒骨架质粒pBHGloxE1,3Cre共转染293A细胞,经包装并获得重组腺病毒,用PCR、酶切及测序方法对其进行鉴定,测定病毒滴度;用重组腺病毒感染VSMCs,用荧光显微镜下观察到的绿色荧光来测定感染率,用RT-PCR和Western blotting法测定hKLK1基因在VSMCs中的表达。结果:PCR、酶切和测序表明携EGFP的重组穿梭质粒pDC316-hKLK1-IRES-EGFP构建正确,并与骨架质粒在293A细胞中成功包装出重组腺病毒Ad-hKLK1-IRES-EGFP,其滴度为4.5×1011/L。重组腺病毒感染VSMCs后,在荧光显微镜下观察到明亮绿色荧光蛋白表达,感染率高达90%以上,可检测到hKLK1基因的mRNA及蛋白表达,并与感染时间(1 d-7 d)有显著依赖关系,峰值感染复数为100 MOI。结论:成功构建并包装了携EGFP和hKLK1基因的双顺反子重组腺病毒载体系统Ad-hKLK1-IRES-EGFP;感染VSMCs可检测到基因hKLK1和EGFP的独立共同高表达,该系统为一直观、安全、高效的基因转移系统。

慢病毒载体介导绿色荧光蛋白基因在小鼠T淋巴细胞中的表达

本研究构建含绿色荧光蛋白基因的慢病毒载体三质粒系统,并观察其在小鼠T淋巴细胞中的表达情况。应用亚克隆技术将多聚嘌呤通道(PPT)元件、泛醌启动子(PUB)和绿色荧光蛋白基因(GFP)连接至pLO134载体,构建成pTK153载体。之后应用磷酸钙沉淀法将慢病毒载体三质粒系统(包括包装质粒△NRF、转移质粒pTK153和包膜蛋白质粒VSV-G)共转染293T细胞,12小时后在荧光显微镜下观察绿色荧光蛋白表达情况,72小时收集病毒上清并感染小鼠T淋巴细胞,在荧光显微镜下和应用流式细胞仪(FACS)观察感染情况。结果表明:慢病毒载体的三质粒系统转染293T细胞12小时后在荧光显微镜下观察到绿色荧光蛋白表达,FACS分析转染效率为(63.04±7.24)%,病毒滴度测定为(3.09±0.61)×106U/ml。感染小鼠T淋巴细胞后,荧光显微镜下观察到GFP的表达,FACS分析转导效率为(37.98±6.26)%。结论:成功构建了含绿色荧光蛋白基因的慢病毒载体,对小鼠T淋巴细胞有较高的感染效率。

绿色荧光蛋白及其在丝状真菌研究中的应用

绿色荧光蛋白(green fluorescent protein,GFP)来源于海洋生物水母(Aequorea victoria),gfp基因作为报告基因已被广泛地应用于丝状真菌生物学研究中。gfp基因通过与目标基因融合,可进行真菌的蛋白质及细胞器定位、细胞动力学、突变体致病力检测、生态学行为以及与其他生物互作等研究。

BDNF重组腺病毒的构建及在大鼠骨髓间质干细胞的表达

目的 :利用大肠杆菌细菌内同源重组构建带有增强型绿色荧光蛋白 (EGFP)报告基因的脑源性神经营养因子前体 (proBDNF)和脑源性神经营养因子 (BDNF)重组腺病毒并在大鼠骨髓间质干细胞 (rMSC)高效表达。方法 :采用两步亚克隆的方法将proBDNF和BDNF构建入带有EGFP表达盒的腺病毒穿梭质粒pAdTrack -CMV中 ,形成转移载体pAdTrack -proBDNF和pAdTrack -BDNF ,采用化学转化法在大肠杆菌BJ5 183内与腺病毒骨架质粒pAdEasy- 1同源重组 ,得到重组腺病毒载体pAd -proBDNF和pAd -BDNF ;转染 2 93细胞 ,包装成重组病毒颗粒 ;将重组病毒上清感染rMSC ,用荧光显微镜下观察和Western -blotting鉴定重组病毒在rMSC表达 ;用Ad -proBDNF和Ad -BDNF感染的rMSC在体外诱导向神经样细胞分化 ;用Ad -proBDNF和Ad -BDNF的感染的rMSC接种于裸鼠肌肉内 ,两周后荧光显微镜下直接观察。结果 :成功地构建了proBDNF和BDNF重组腺病毒载体并制备出高滴度重组病毒 ,重组病毒能在体外培养的rMSC高效表达并不影响其分化潜能 ,体内移植实验表明Ad -proBDNF和Ad -BDNF感染的rMSC能在体内表达。结论 :重组腺病毒具有较高的介导proBDNF和BDNF基因表达于rMSC的效率 ,带有报告基因EGFP的Ad -proBDNF和Ad -BDNF感染的rMSC可以用于体内移植实验。