用荧光强度反映Cbfa1活性成骨细胞模型的构建

目的构建稳定表达由6OSE2启动子驱动的增强型绿色荧光蛋白(EGFP)的MG63细胞株,并筛选出能反映Cbfa1活性的细胞株。方法合成6OSE2启动子的序列,并将其构建到T载体中;然后通过双酶切得到启动子片段;与去除CMV启动子的报告基因载体pEGFP-N1的酶切片段连接,构建真核表达载体;并转染到MG63细胞系,经G418筛选得到了稳定转染6OSE2-EGFP基因的MG63细胞株。用不同浓度的IGF-I和VD3处理,通过EGFP荧光强度分析,ALP活性测定,筛选出能够响应IGF-I和VD3的细胞株。结果构建了pUC-6OSE2扩增载体和p6OSE2-EGFP真核表达载体,通过稳定转染以及IGF-I、VD3筛选获得一株荧光强度随IGF-I和VD3处理而增强的细胞株-OSE-MG63。结论构建了能反应Cbfa1活性的成骨细胞模型,为进一步研究微重力对Cbfa1的转录活性及信号传导途径的影响奠定了基础。     

EOLA1基因小干扰RNA载体构建及其干扰效应检测

目的 构建人类新基因内皮高表达脂多糖相关因子1(EOLA1)特异性的小干扰RNA表达载体,并初步验证其对靶基因的抑制作用。方法 构建绿色荧光蛋白(GFP)-EOLA1融合蛋白表达载体pEGFP-N2／EOLA1,并转染人ECV304细胞株,G418压力筛选获得稳定表达株;针对靶基因EOLA1,设计靶点特异性的寡核苷酸,插入pSlincer3．1／H1质粒。转染重组质粒到稳定表达GFP-EOLA1融合蛋白的ECV304细胞,通过观察转染细胞绿色荧光的强弱和Westem blot实验检测靶基因的抑制情况。结果 获得了稳定表达GFP-EOLA1融合蛋白的细胞株,构建的小RNA干扰质粒siEOLA1能够抑制靶基因EOLA1的表达。结论 成功构建了针对EOLA1基因的siRNA质粒,为进一步研究该基因的功能奠定了基础。     

用荧光强度反映Cbfal活性成骨细胞模型的构建

目的 构建稳定表达由60SE2启动子驱动的增强型绿色荧光蛋白(EGFP)的MG63细胞株,并筛选出能反映Cbfal活性的细胞株.方法 合成60SE2启动子的序列,并将其构建到T载体中:然后通过双酶切得到启动子片段;与去除CMV启动子的报告基因载体pEGFP-Nl的酶切片段连接,构建真核表达载体;并转染到MG63细胞系,经G418筛选得到了稳定转染60SE2-EGFP基因的MG63细胞株.用不同浓度的IGF-I和VD,处理,通过EGFP荧光强度分析,ALP活性测定,筛选出能够响应IGF-I和VD3的细胞株.结果 构建了pUC-60SE2扩增载体和p60SE2-EGFP真核表达载体,通过稳定转染以及IGF-I、VD_3筛选获得一株荧光强度随IGF-I和VD_3处理而增强的细胞株.OSE-MG63.结论 构建了能反应Cbfal活性的成骨细胞模型,为进一步研究微重力对Cbfal的转录活性及信号传导途径的影响奠定了基础.     

稳定转染小鼠IL-17全长基因的乳腺癌细胞株的建立及基因转染对4T1细胞的影响

目的建立稳定转染小鼠IL-17基因全长的小鼠乳腺癌4T1细胞株,并进行鉴定。方法脂质体法将携带小鼠IL-17基因全长的真核表达载体pcDNA3．1转染小鼠乳腺癌细胞4T1,经G418筛选出稳定表达IL-17的细胞株;镜下观察细胞形态,RT-PCR法、Western印迹和激光共聚焦法检测目的基因和蛋白的表达;收集转染和未转染IL．17的4T1细胞的培养上清,分别与巨噬细胞RAW264．7共培养,ELISA法检测RAw264．7细胞培养上清中IL-6水平;MTS法检测细胞的增殖情况,流式细胞技术检测细胞周期、凋亡以及细胞表面MHCI、MHC11、淋巴细胞功能相关抗原-1（LFA-1）等分子表达。结果获得1株稳定表达IL-17的4T1细胞,而且其培养上清可刺激小鼠巨噬细胞RAW264．7产生IL-6,证明该细胞可表达功能性IL-17。结论成功建立了稳定转染IL-17基因的小鼠乳腺癌细胞株。     

反映成骨细胞特异转录因子Runx2活性的细胞模型构建

目的 构建稳定表达由6OSE2启动子驱动的萤火虫荧光素酶的小鼠C2C12成肌细胞,并筛选出能定量反映Runx2活性的细胞株.方法 双酶切pUC57-6OSE2,获得启动子片段;插入到消化后的pGL4.14,构建真核表达载体;随后将其转染到C2C12细胞中;用潮霉素B筛选获得稳定转染的细胞株C2C12-6OSE2-Luc...     

乙型肝炎病毒前-S2蛋白对硫氧还蛋白还原酶1基因表达的上调作用研究

目的 探讨乙型肝炎病毒(HBV)前-S2蛋白对硫氧还蛋白还原酶1(TXNRDl)启动子转录的激活作用。方法 以302院传染病研究所基因治疗研究中心自行构建的乙型肝炎病毒前-S2蛋白反式调节的基因表达谱芯片结果为基础,利用生物信息学技术确定TXNRD1的启动子区域(TXNRD1p),PCR扩增TXNRD1p,克隆至真核报告载体pCAT3-Basic中,构建pCAT3-TXNRD1p报告载体;以该质粒转染肝癌细胞系HepG2细胞系,用ELISA法检测氯霉素乙酰转移酶(CAT)的表达活性;并与pcDNA3．1(-)-preS2共转染HepG2细胞系,用ELISA法检测CAT的表达活性。结果pCAT3-TXNRDlp和pcDNA3．1（-）-preS2瞬时转染的HepG2细胞的CAT表达活性是pCAT3-Basic空载体的5．7倍、pCAT3-TXNRDlp的2．2倍。结论 该TXNRD1启动子有顺式激活下游基因的活性;HBV的前-S2蛋白具有反式激活TXNRD1的作用。     

Schlafen2基因在细胞中的表达及其生物学特性研究

目的:建立Schlafen2(Slfn2)基因稳定表达的细胞系以进一步研究其生物学功能.方法:构建pEGFP- Slfn2真核表达载体;瞬时转染pEGFP- Slfn2载体及其对照载体于NIH/3T3细胞,观察细胞中Slfn2基因的表达及分布;稳定转染pEGFP-Slfn2及其对照空载体于NIH/3T3细胞,G418筛选获得抵制的细胞株,用Northern印迹进一步鉴定Slfn2在各细胞株中的表达情况;利用细胞生长曲线和Transwell细胞侵袭实验检测Slfn2对细胞增殖及迁移能力的影响.结果:本研究获得了稳定表达Slfn2的细胞株,该基因表达的蛋白在细胞核及细胞浆均有分布;稳定表达该基因的细胞株的增殖及迁移能力均显著降低.结论:Slfn2基因可能是一个潜在的肿瘤抑制基因.     

骨唾液蛋白非融合荧光蛋白载体的构建及其在特异性骨转移乳腺癌细胞中的稳定表达

目的 构建骨唾液蛋白(BSP)非融合荧光表达载体,建立稳定高效表达BSP和荧光蛋白的乳腺癌细胞系,为进一步研究BSP在乳腺癌细胞骨转移中的作用奠定基础。方法 从构建好的pB-hBSP载体中用PCR方法扩增hBSP基因,通过BglⅡ和PstⅠ两个限制性酶切位点定向克隆至真核表达载体pIRES2一EGFP,构建重组载体pIRES2-hBSP-EGFP。利用脂质体转染的方法将构建好的重组质粒转入特异性骨转移的乳腺癌细胞株MDA-MB-23180中,并利用G418和流式细胞仪筛选阳性克隆。结果 成功构建hBSP和EGFP非融合表达的真核表达载体pIRES2-hBSP EGFP,并成功转染特异骨转移的乳腺癌细胞株,获得hBSP的稳定转染细胞株,荧光显微镜下可观察到荧光蛋白标记。结论 真核表达载体CRFS2-hBSP-EGFP的构建及hBSP稳定转染细胞株的获得为研究BSP在乳腺癌骨转移中的作用奠定了的基础。     

人中性粒细胞多肽1真核表达载体的构建与表达

目的 构建人中性粒细胞多肽1(HNPl)基因真核表达载体,为探讨HNP1基因工程生产的可能性奠定基础。方法 从健康人中性粒细胞中提取总RNA,用RT-PCR方法扩增出HNPl基因cDNA片段,将纯化PCR产物与pMD18-T载体连接,经酶切鉴定及测序确证,将其亚克隆入真核表达载体pcDNA3．1／V5-His-TOPO中．用脂质体转染CA3S-7细胞,用BA-ELISA法检测转染细胞上清中HNP1的表达。结果 从人中性粒细胞中克隆出人HNP1基因,经测序分析与GenBank公布的人HNP1核苷酸序列完全一致,并在COS-7细胞中获高效瞬时表达。结论 成功构建了真核表达载体pcDNA3．1／V5-His-TOPO／HNP1,为后续哺乳动物工程细胞株的建立奠定了实验基础。     

稳定表达人MAGE-1基因的小鼠细胞系的建立与鉴定

目的：克隆人黑素瘤抗原-1（MAGE-1）基因，构建真核表达载体，建立稳定表达人MAGE-1的小鼠细胞株。方法：提取人肝癌细胞的总RNA，RT-PCR法获得人MAGE-1cDNA，将测序正确的MAGE-1基因克隆至真核表达载体pcDNA3中，进行酶切鉴定和序列测定。将重组质粒pcDNA／MAGE和空载体pcDNA3分别转染入小鼠骨髓瘤细胞SP2／0中，经G418筛选获得稳定表达株，用RT-PCR和Western印迹检测MAGE-1基因的转录及蛋白表达。结果：从肝癌细胞中成功克隆到人MAGE-1基因，经测序证明基因正确，酶切和序列测定表明，人MAGE-1基因的真核表达质粒已成功构建。将此重组质粒转入的SP2／0细胞可稳定表达人MAGE-1基因。结论：成功构建可稳定表达人MAGE-1基因的小鼠转基因细胞，为MAGE-1的免疫治疗研究奠定了基础。     

Noninvasive monitoring of target gene expression by imaging reporter gene expression in living animals using improved bicistronic vectors.

Indirect, noninvasive imaging of therapeutic gene expression based on levels of reporter gene expression is a powerful tool to devise improved therapeutic strategies in cancer gene therapy. The use of bicistronic vectors carrying internal ribosome entry sites (IRESs) allows the coexpression of multiple gene products from the same promoter but leads to considerable attenuation of the downstream gene. In this study, we describe the use of 10 linked copies of the Gtx (homeodomain protein) IRES (abbreviated as SIRES) in place of the encephalomyocarditis (EMCV) IRES in mediating downstream reporter gene expression in cell culture and in vivo. METHODS: We constructed several plasmid vectors carrying different upstream and downstream reporter genes (herpes simplex virus type I thymidine kinase [tk], firefly luciferase [fl], and Renilla luciferase [rl]) placed between EMCV IRES and SIRES segments. RL, FL, and TK enzyme activities in N2a, C6, and 293 cells transiently transfected with these vectors were found to be significantly higher for the SIRES vectors than for the EMCV IRES vectors. For in vivo experiments, 4 stably transfected N2a cell lines were implanted in nude mice. The mice were imaged for rl and fl gene expression using a charged-coupled device (CCD) camera. For bioluminescence and microPET imaging of downstream gene expression of fl and tk genes, respectively, mice carrying 4 stably transfected xenografts were imaged using the CCD camera and microPET. RESULTS: In cell culture, using rl as the upstream gene, we demonstrate that the expression of the downstream tk gene is 12-fold greater using SIRES when compared with EMCV IRES. Furthermore, the expression of the 2 genes was highly correlated in N2a cells. In vivo bioluminescence imaging using 4 stably transfected N2a cell lines revealed increasing levels of rl and fl gene expression. Bioluminescence and microPET, respectively, of fl and tk reporter gene expression in nude mice bearing N2a tumor xenografts showed the gene expression mediated by SIRES to be 4- and 8-fold higher, respectively, than EMCV IRES. CONCLUSION: These findings support the use of SIRES bicistronic vectors for a better assessment of therapeutic gene expression based on reporter gene expression in living subjects.     

The human norepinephrine transporter in combination with 11C-m-hydroxyephedrine as a reporter gene/reporter probe for PET of gene therapy.

Although the herpes simplex virus thymidine kinase gene has been frequently applied as a reporter gene for monitoring gene transfection in animals, it has some intrinsic limitations for use in humans. In our search for a reporter gene that lacks these limitations, we have evaluated the feasibility of the human norepinephrine transporter (hNET) as a reporter gene in combination with the reporter probe 11C-m-hydroxyephedrine (mHED) for PET. METHODS: An adenoviral vector (AdTrack-hNET) containing the hNET gene as reporter gene and the enhanced green fluorescent protein (EGFP) as a substitute for a therapeutic gene was constructed. After COS-7, A2780, and U373 cells were transiently transduced with AdTrack-hNET, hNET protein expression, EGFP fluorescence, and cellular uptake of 11C-mHED were determined. In rats, U373 tumor xenografts were grown and transiently transduced with either AdTrack-hNET or an AdTrack-Luc control adenovirus. Intratumoral accumulation of 11C-mHED was determined by PET and ex vivo biodistribution. The tumors were subsequently examined for EGFP fluorescence. RESULTS: 11C-mHED uptake was positively correlated with AdTrack-hNET viral titer and hNET protein expression. However, large differences in transfection efficiency between cell lines were observed. The highest 11C-mHED uptake was found in hNET transfected U373 cells, in which tracer uptake was >70-fold higher than that in control cells. 11C-mHED accumulation could be inhibited by desipramine, a potent inhibitor of hNET. In all cell lines, 11C-mHED uptake was positively correlated with EGFP fluorescence, implying that imaging of hNET with 11C-mHED would enable monitoring of a coexpressed therapeutic gene. In the animal model, gene transfection efficiencies were very low, as determined by EGFP fluorescence. Still, a significantly higher 11C-mHED uptake in hNET transduced tumors than that in control tumors was demonstrated by ex vivo biodistribution studies. PET with a clinical camera could visualize 1 of 3 hNET transduced tumors, indicating that the transfection efficiency was near the detection limit. CONCLUSION: These results indicate that monitoring of gene therapy using the hNET/11C-mHED reporter gene/probe is feasible, but further investigation with regard to the sensitivity of the technique is required.     

肝特异性假病毒转运系统的构建

目的:探索一种针对慢性乙型肝炎的特异性长效基因治疗手段.方法:改造乙型肝炎病毒(hepatitis B virus,HBV)为基因治疗载体,敲除其所有的开放阅读框(open reading frames,ORFs),同时保留包装信号序列,并且插入增强绿色荧光蛋白(enhanced green fluorescent protein,EGFP)作为报告基因.同时构建辅助细胞系,为上述病毒载体(假病毒)提供包装所需要的病毒蛋白.以该假病毒载体转染辅助细胞系,以酶联免疫方法检测细胞培养上清中乙型肝炎病毒抗原,并在荧光显微镜下观察EGFP的表达,用透射电镜观察培养上清中的病毒颗粒,同时用实时定量PCR的方法对分泌到细胞培养上清中的假病毒进行了定量检测.结果与结论:以假病毒载体转染辅助细胞后,电镜观察到培养上清中乙肝病毒的丹氏粒(Dane particle).实时定量PCR分析结果显示,细胞分泌到培养上清的假病毒含量达103拷贝/μl.ELISA结果显示该上清中同时表达了HBV表面抗原和e抗原,通过荧光显微镜观察发现外源基因绿色荧光蛋白获得有效表达.     

内质网应激对ATF6调控XBP1启动子转录的影响

目的 确定XBP1启动子的转录核心区域,探讨激活转录因子6(ATF6)在内质网应激(ERS)与非ERS状态下对XBP1启动子转录活性的调控作用.方法 采用基因重组技术构建ATF6基因及两个缺失体ATF6s1p、ATF6s2p的真核表达载体pcDNA3.1 (-)-ATF6、pcDNA3.1 (-)-s1p、pcDNA3.1(-)-s2p,以及XBP1启动子报告基因载体pGL3-XBP1.针对XBP1启动子的各个组成元件设计和构建XBP1一系列截短体的报告基因载体.采用双荧光素酶报告基因法检测并确定XBP1启动子的核心启动子区,Western blotting检测ATF6及缺失体s2p、s1p在ERS与非ERS状态下对XBP1核心启动子区转录的调控作用.结果 XBP1启动子的-407bp-+133bp区域是转录活性调控的核心区域,-2000bp--407bp区域不具有转录活性,该区域可能含有抑制转录活性的组成元件.非ERS状态时,ATF6及两个缺失体s2p、s1p可明显上调XBP1启动子的转录活性及XBP1蛋白表达;而在ERS状态时,ATF6及两个缺失体s2p、s1p下调了XBP1启动子的转录活性和XBPl蛋白表达.结论 ATF6对XBP1的转录调控作用在ERS状态和非ERS状态下存在差异.非ERS状态时,ATF6上调XBP1的转录和表达,而ERS状态时,ATF6下调XBP1的转录和表达.     

重组HIF—1α及NIS慢病毒表达载体的构建及功能鉴定

目的构建肌凝蛋白轻链-2（MLC-2v）启动下HIF-1α及人NIS慢病毒真核表达载体,探讨外源基因在心肌细胞中的特异性表达和NIS作为报告基因的可行性。方法应用基因重组技术构建慢病毒（Lv）-延长因子（EF）1-HIF-1α-内部核糖体进入位点（IRES）-NIS及Lv-MLC-HIF-1α-IRES-NIS慢病毒表达载体。对重组质粒进行酶切、测序鉴定后,采用脂质体转染法将重组质粒转入Hela细胞。细胞免疫荧光及Westernb1a分别验证HIF-1α及NIS蛋白在细胞中的定位及定量表达;制备重组病毒,分别以不同的感染复数（MOI）感染H9C2大鼠心肌细胞、NIH-3T3小鼠胚胎成纤维细胞和L6大鼠骨骼肌成肌细胞,Westernb1a确定最佳MOI并验证MLC·2v启动子的特异性;分别行H9C2细胞动态摄碘和NaClO4抑制实验。采用两样本t检验分析数据。结果成功构建Lv-EFl-HIF-1a-IRES-NIS及Lv-MLC-HIF-1α-IRES-NIS慢病毒表达载体。2种质粒分别转染Hela细胞,免疫荧光显示HIF-1α蛋白表达于胞质,NIS蛋白表达于胞膜;Westernb1a显示EFl启动下2种蛋白质的表达量多于MLC-2v启动下相应表达。Westernb1a蛋白检测后测定蛋白灰度值,阳性对照组NIS及HIF-1α灰度值分别为69-8和71-9,EF1启动下分别为109-4和92-7,MLC-2v启动下分别为141-9和132-4。Lv-MLC-HIF-1α-IRES-NIS病毒感染H9C2细胞,MOI为20时NIS蛋白表达最高,为最佳MOI。2种病毒以MOI为20分别感染H9C2、NIH-3T3及L6细胞,Westernb1a显示EF1启动下NIS蛋白在3种细胞中均有表达,灰度值分别为23.4、29.8和28.6,相差较小。MLC-2v启动下仅H9C2细胞中有大量NIS蛋白表达,NIS蛋白在H9C2、L6及NIH-3T3细胞的灰度值分别为157.9、178.8和2173。H9C2细胞的摄碘高峰时间为40min,峰值为4287.2计数·min-1,是阴性对照组（254.g计数·min-1）的16.85倍（t=5.34,P〈0.01）。摄碘可被NaC国O4抑制,抑制率达85.5％（t=21.3,P〈0.01）。结论MLC-2v可启动治疗基因HIF-1α及报告基因NIS在心肌细胞中特异性表达,表达的NIS蛋白具有摄碘功能,为NIS作为报告基因监测外源基因的靶向治疗奠定了基础。     

辐射诱导性启动子调控GM—CSF基因的表达

构建携带早期生长反应基因（Egr-1)启动子的GM-CSF和增强绿色荧光蛋白（EGFP）双顺反子基因表达载体（Egr-EG)。通过脂质体转染骨髓基质细胞系HFCL（称为HFCL/EG）,采用FACS分析EGFP表达的阳性细胞,用RT-PCER、ELISA及集落增殖法分析GM-SCFmRNA、GM-CSF含量的表达及对CFU-GM抚养殖作用。结果显示：HFCL/EG细胞证实有外源性基因EGFP和GM-CSF的整合和表达及对CFU-GM的增殖作用。提示Egr-1调控序列启动的GM-CSF基因修饰的基质细胞经辐射造血因子表达明显增高,并对造血细胞具有一定的保护作用。