整合素β1表达上调对肺癌细胞迁移和粘附能力的影响

目的:构建整合素β1的全基因表达载体,并探讨上调整合素β1蛋白表达对肺癌细胞生物学行为的影响.方法:根据GenBank数据库提供的整合素β1基因核苷酸序列,构建整合素β1的全基因表达载体,同时将空载体pCDNA3.1作为阴性对照.将载体转入感受态大肠杆菌,挑选阳性克隆,抽取重组栽体.2种重组栽体转染非小细胞肺癌细胞株PC-9细胞,用G418筛选后挑选单克隆并扩增获得稳定株.荧光显微镜、Real-time RT-PCR、Western blot检测整合素β1的基因及蛋白水平的表达情况.细胞划痕试验和粘附试验比较整合素β1对细胞迁移、粘附能力的影响.结果:G418筛选出稳定转染整合素β1全基因表达栽体和空载体的细胞,分别命名为PC-9/D6和PC-9/PCD.荧光显微镜见满视野带绿色荧光的细胞,PC-9/D6细胞整合素β1的mRNA、蛋白表达明显高于对照的PC-9/PCD细胞及母细胞PC-9.划痕试验和粘附试验表明整合素β1过表达的细胞株的迁移和粘附能力明显提高.结论:成功转染并筛选出整合素β1过表达细胞株,整合素β1过表达的细胞株的迁移和粘附能力明显升高.     

干扰素膜蛋白Tet-on系统稳定细胞系的建立及对CA16病毒的抑制作用

通过Tet-on调控系统,构建受多西环素诱导表达干扰素诱导的跨膜蛋白(interferon-induced transmembrane proteins 1/2/3,IFITM1/2/3)基因的HeLa细胞系,并初步探索了IFITM蛋白对柯萨奇病毒A16(CA16)的抑制作用.首先将调控质粒pTet-on转染进入HeLa细胞,通过G418筛选出阳性克隆细胞系,在此细胞系基础上共同转染反应质粒pTRE2-IFITM1/2/3和伴侣质粒pTK-Hyg,通过潮霉素筛选出单克隆细胞系,加入多西环素后利用Western印迹筛选出可诱导表达IFITM1/2/3蛋白的单克隆细胞系.使用实时荧光定量PCR(RT-qPCR)检测发现,多西环素诱导表达的IFITM蛋白对不同感染复数(multiplicity of infection,MOI)的CA16具有明显的抑制作用,其中IFITM 3对CA16的抑制效果最为明显.Tet调控IFITM1/2/3基因表达HeLa细胞系的成功建立,为进一步研究IFITM基因的功能及其抗病毒机理提供了一个理想的细胞模型.     

靶向白介素-1α基因沉默的Hela229稳定细胞系的构建

目的：构建针对IL-1α基因的shRNA表达载体,筛选能够抑制Hela229细胞内源性IL-1α表达的shRNA,建立无内源性IL-1d表达的Hela229稳定细胞系.方法：根据shRNA的设计原则,以IL-1 αcDNA oligo为模板设计一段21 bp核苷酸目标序列,构建成siRNA的DNA模板并克隆到shRNA表达载体pRNAT-U6.1/Neo中,获得靶向抑制IL-1α基因的重组shRNA质粒,转染Hela229细胞,经G418筛选后获得单克隆稳定细胞株,用ELISA方法在蛋白水平上检测IL-1α基因的沉默效果.结果：经酶切鉴定和测序分析确定IL-1 α-shRNA重组质粒构建正确,ELISA筛选出能够显著抑制内源性IL-1α表达的shRNA,获得沉默内源性IL-1 α表达的单克隆稳定的Hela229细胞株.结论：靶向IL-1α基因的重组shRNA表达质粒可显著抑制Hela229细胞内源性IL-1α的表达,成功构建靶向IL-1α基因沉默的Hela229稳定细胞系.     

TGF-β1基因真核表达载体的构建及在BMSCs中的表达

目的研究真核表达载体pCDNA3.1( )-TGF-β1在骨髓间充质干细胞(BMSCs)中的表达.方法基因克隆构建pCDNA3.1( )-TGF-β1真核表达载体,转染大鼠BMSCs,G418筛选获得稳定转染的细胞,RT-PCR、ELISA和免疫细胞化学检测其表达,MTT法检测其增殖活性.结果成功构建含TGF-β1基因的真核表达载体;RT-PCR、ELISA、免疫细胞化学证实了TGF-β1基因在BMSCs中至少可以表达一个月;MTT法提示转染TGF-β1基因可以促进BMSCs增殖.结论 pCDNA3.1( )-TGF-β1转染BMSCs可获得稳定表达.     

四环素诱导可控表达细胞周期素B1单克隆的筛选

目的筛选四环素诱导细胞周期素B1（CyclinB1）可控表达的293单克隆细胞株（tetracycline-regulated expression 293 cells,T-REx^TM-293）。方法从人胎肝cDNA文库中PCR带有酶切位点的CyclinB1基因全长,将其酶切后插入到pcDNA4／TO／myc-HisB载体中。然后用测序正确的质粒转染T-RExTM-293细胞,加杀稻瘟菌素（Blasticidin）和腐草霉素（Zeocirt）双药物筛选两周后,传96孔板,等单个细胞扩增出单克隆。然后用Western印迹和流式细胞仪检测CyclinB1的诱导表达情况。结果构建好的pcDNA4／TO／myc-HisB—CyclinB1载体,经鉴定序列正确。筛选出的单克隆细胞株,在未加四环素时没有外源性的CyclinB1表达,在加入四环素后,3h就有表达,随时间的增加,CyclinB1表达量也增加,48h最多。结论筛选出的T-REx^TM-293单克隆细胞株能可控表达CyclinB1。     

过表达Daintain促进RAW264.7细胞增殖和吞饮功能

[目的]研究过表达Daintain对巨噬细胞RAW264.7增殖和吞饮功能的影响。[方法]培养RAW264.7细胞,脂质体法导入过表达Daintain的质粒(pc DNA-DT)和空质粒(pc DNA),经G418筛选单克隆细胞株。Western Blot检测稳定转染细胞株中Daintain的表达,MTT法检测Daintain过表达对RAW264.7细胞增殖的影响,中性红染色法检测Daintian过表达对LPS诱导的RAW264.7细胞吞饮功能的影响。[结果]1对比转染pc DNA质粒的细胞株,转染pc DNA-DT质粒的细胞株中Daintian表达量增加28.7%,说明成功建立稳定过表达Daintian的RAW264.7细胞株;2在48h和72h,相对转染pc DNA的细胞株,转染pc DNA-DT的细胞株增殖明显增强;3在0.1和1μg/m L LPS诱导下,相对转染pc DNA的细胞株,转染pc DNA-DT的细胞株的吞饮作用增强。[结论]过表达Daintain促进RAW264.7细胞增殖和吞饮功能。     

在表达HCV Core蛋白的肝癌细胞中建立Notch1低表达稳定转染细胞株

目的筛选并包装Notch1基因shRNA低表达的慢病毒,感染稳定表达丙型肝炎病毒(hepatitis C virus,HCV)核心蛋白(core)的肝癌细胞,在此基础上建立低表达Notch1基因的SMMC7721-Core稳定转染细胞株。方法设计针对Notch1基因mRNA的干扰序列,并将其连接入载体质粒,转染HEK293T细胞,构建带有Notch1基因的慢病毒表达载体,感染稳定表达HCV Core蛋白的人肝癌细胞株SMMC7721-Core,采用定量聚合酶链反应(quantitative PCR,qPCR)和免疫印迹法(Western blot)检测干扰效果。结果构建了带有干扰Notch1基因的慢病毒表达载体,感染SMMC7721-Core细胞后筛选获得稳转细胞株,qPCR测得Notch1 mRNA低表达,Western blot检测到Notch1蛋白低表达。结论成功构建了Notch1低表达SMMC7721-Core人肝癌稳定转染细胞株,为进一步开展对HCV Core蛋白诱导肝癌过程中Notch1所起作用的研究提供了依据。     

人TBK1小干扰RNA质粒的构建及稳定干扰TBK1细胞株的筛选

目的:构建人TANK结合激酶1(TBK1)的小干扰RNA真核表达质粒,并筛选出稳定干扰TBK1的细胞株。方法:根据文献报道的序列和载体的黏性末端,设计合成2条针对TBK1的DNA序列,退火后连接到载体pSUPER.retro.neo+gfp上,经测序分析正确后得到质粒psiTBK1。用脂质体转染质粒psiTBK1到MCF-7细胞中,经G418加压筛选稳定表达TBK1小干扰RNA的细胞株,用免疫印迹检测细胞中TBK1的表达情况,将干扰效果好的细胞株命名为MCF-7/siTBK1,再用萤光素酶试验检测MCF-7/siTBK1细胞对外源TBK1诱导干扰素-β(IFN-β)转录的情况。结果:免疫印迹结果证实建立的稳定细胞株MCF-7/siTBK1能够有效干扰TBK1的表达,并在外源TBK1存在的情况下抑制IFN-β的转录活性。结论:构建了表达TBK1小干扰RNA的质粒psiTBK1,筛选出稳定干扰TBK1表达的细胞株MCF-7/siTBK1,为深入研究TBK1在先天免疫中的作用提供了平台。     

一株受二噁英类化学物质诱导表达的萤光素酶肝癌细胞系

 构建了一对二英类化学物质敏感的人肝癌细胞株 ,用于二英类化学物质生物筛选和快速半定量检测 .首先构建一在二英增强子调控下的萤光素酶报告基因质粒 ,该质粒转染入人肝癌细胞株HepG2 ,筛选稳定转染细胞株 .2 ,3,7,8 四氯代二苯并二英 (TCDD)诱导稳定转染细胞株萤光素酶表达 ,发光检测萤光素酶活性 .该细胞株用于TCDD检测 ,检测下限为 1 1pmol L ,线性范围为 1～ 10 0pmol L .该细胞系的建立可用于二英类化学物质的生物筛选和快速半定量检测     

一株受二噁英类化学物质诱导表达的萤光素酶肝癌细胞系

构建了一对二英类化学物质敏感的人肝癌细胞株 ,用于二英类化学物质生物筛选和快速半定量检测 .首先构建一在二英增强子调控下的萤光素酶报告基因质粒 ,该质粒转染入人肝癌细胞株HepG2 ,筛选稳定转染细胞株 .2 ,3,7,8 四氯代二苯并二英 (TCDD)诱导稳定转染细胞株萤光素酶表达 ,发光检测萤光素酶活性 .该细胞株用于TCDD检测 ,检测下限为 1 1pmol L ,线性范围为 1～ 10 0pmol L .该细胞系的建立可用于二英类化学物质的生物筛选和快速半定量检测     

Receptor-targeted recombinant adenovirus conglomerates: a novel molecular conjugate vector with improved expression characteristics.

To develop improved strategies for gene transfer to hematopoietic cells, we have explored targeted gene transfer using molecular conjugate vectors (MCVs). MCVs are constructed by condensing plasmid DNA containing the gene of interest with polylysine (PL), PL linked to a replication-incompetent adenovirus (endosomolytic agent), and PL linked to streptavidin for targeting with biotinylated ligands. In this report, we compare gene transfer to K562 cells by using the previously described transferrin-targeted MCV (Trans-MCV) to a novel transferrin-targeted MCV. In the novel MCV, the transferred gene (luciferase) is in the genome of recombinant replication-incompetent adenovirus (recMCV), which also acts as the endosomolytic agent. The level of luciferase gene expression was fivefold higher in K562 cells transfected with Trans-recMCV than in cells transfected with Trans-MCV. Furthermore, targeted transfection with recMCV resulted in prolonged luciferase expression that declined 14 to 20 days after transfection, in comparison with Trans-MCV, where luciferase expression declined by 4 to 8 days. Moreover, targeted transfection of K562 cells with the Trans-recMCV resulted in persistent luciferase gene expression for 6 months. Analysis of luciferase gene expression in K562 single-cell clones that were subcloned 5 weeks after transfection with Trans-recMCV showed that 35 to 50% of the single-cell clones had intermediate to high levels of luciferase gene expression that was stable for 6 months, with the remaining clones showing low or no luciferase gene expression. Stable gene expression was associated with integration of adenovirus sequences into genomic DNA.     

LipofectAMINE2000与Fugene6转染细胞的效率比较

目的:比较LipofectAMINE2000与Fugene6转染细胞的效果。方法:将含有Firefly和Renilla荧光素酶基因的质粒分别用LipofectAMINE2000和Fugene6转染293T、HepG2和DLD-1细胞,于48h后裂解细胞测定荧光素酶活性。结果:在293T细胞中,LipofectAMINE2000转染组的萤火虫(Firefly)和Renilla荧光素酶活性分别是Fugene6转染组的6.5和5.6倍(P<0.005);在HepG2细胞中,LipofectAMINE2000转染组的Firefly和Renilla荧光素酶活性分别是Fugene6转染组的44和49倍(P<0.001);而在DLD-1细胞中,两者无差别。结论:转染试剂LipofectAMINE2000和Fugene6对不同细胞的转染效果存在差异,当进行转染实验时,对于不同的细胞须根据情况进行选择。     

过表达Runx2促进C2C12细胞成骨分化

利用Tet-on(Tetracycline-on)基因表达系统,通过强力霉素(doxycycline,DOX)诱导Runx2基因在C2C12细胞中的表达,探究Runx2促成骨分化功能,为其分子机制的研究提供一个理想的实验平台.先后将调控质粒pTet-on和反应质粒pTRE-Flag-Runx2转染入C2C12细胞,并用G418和潮霉素分别进行2轮筛选,运用实时荧光定量PCR选择对强力霉素诱导敏感的细胞克隆.用不同浓度DOX诱导C2C12/Tet/pTRE-Flag-Runx2细胞,蛋白免疫印迹检测Runx2的表达,确定DOX的最佳诱导浓度与时间,并检测C2C12细胞的成骨分化能力.结果表明,诱导细胞最佳DOX浓度为10μg/ml;最佳诱导时间为12h;诱导后Runx2基因高表达,C2C12细胞向成骨方向分化(P0.05).成功建立Tet调控Runx2基因表达C2C12细胞系,为进一步研究Runx2基因功能分子机制提供理想的细胞模型.     

A versatile chondrogenic rat calvaria cell line R-tTA-24 that permits tetracycline-regulated gene expression

The clonal rat calvaria cell line RCJ3.1C5.18 (RCJ) undergoes chondrogenic differentiation after long-term culture post confluence. To allow flexible genetic manipulation, a tetracycline-regulated gene expression system was established in this cell line. Treatment with tetracycline in operational doses does not affect the differentiation of RCJ cells with respect to the markers tested. After stable transfection with pUHD15.1 containing the tetracycline transactivator (tTA) in the presence of pTK-hyg for hygromycin selection, 28 clones were isolated and characterized for alcian blue staining of cartilage-specific proteoglycans and for collagen type II expression. Clone R-tTA-24 was selected on the basis of phenotype and displayed tetracycline-dependent downregulation of luciferase activity (tet-OFF system) by two orders of magnitude (57–149-fold) after stable transfection with the reporter gene pBI-EGFP/luc. The novel, chondrogenic cell line R-tTA-24 may be stably transfected with various genes of interest for tetracycline- regulated gene expression using neomycin selection and may be a valuable tool to study the process of chondrogenic differentiation in vitro. Accepted: 30 November 1999     

Nonviral gene transfer into primary cultures of human and porcine mesothelial cells

Due to their abundance and accessibility, mesothelial cells may be suitable tools for recombinant reagent expression by gene transfer. Genetically modified porcine mesothelial cells (PMCs) may have the potential for the treatment of vascular diseases in humans. We studied the effect of various transfection reagents on the primary culture of PMCs and human mesothelial cells (HMCs). The cells were transfected with a plasmid encoding a reporter gene (luciferase or green fluorescent protein [GFP]) under the control of the cytomegalovirus promoter. Transfection was achieved using cationic lipids (DOSPER and DOTAP) or calcium phosphate/deoxyribonucleic acid coprecipitation or Fugene 6. Results showed that Fugene 6 was the most efficient and reproducible transfection reagent with both PMCs and HMCs. With Fugene 6, luciferase activity in PMCs (1.5 x 10(8) relative light units [RLU]/10(6) cells) was at least 2.5-fold higher than with the other transfection reagents, and it was 100-fold higher than in HMCs. However, the proportion of transfected cells expressing GFP was only 1%. These preliminary findings open up new avenues for developing experimental studies on the use of genetically modified PMCs.     

Establishment of an IFN-γ specific reporter cell line in fish

An interferon (IFN)-γ responsive stable cell line RTG-3F7 has been developed for rainbow trout by modifying the RTG-2 cell line through transfection with a plasmid construct (pGL4.14[luc2/hygro]-PrTAP2) containing a promoter element from the IFN-γ responsive gene TAP2 linked to a luciferase reporter gene and a hygromycin resistance gene. Following transfection single clones were selected in 96 well plates using hygromycin B, and those showing specific activation after rIFN-γ stimulation were maintained. Five clones that showed the highest reporter activity to rIFN-γ were incubated with different stimuli to examine specificity. No significant induction of luciferase was observed following exposure to recombinant type I IFN, LPS, PHA or poly I:C. The cell line was responsive to rIFN-γ at concentrations between 150 pg and 20 ng ml^?1. Supernatants of primary cultures of head kidney leucocytes stimulated with PHA, known to induce IFN-γ gene expression, were also used to assess the reporter activity of the stable cell line. A dose-dependent induction of the promoter activity was observed with these supernatants indicating the presence of IFN-γ. These results indicate that the stable cell line RTG-3F7 is an excellent tool for monitoring the presence of trout IFN-γ in biological samples, and in addition, enables the study of intracellular signalling pathways of IFNs, their receptor interactions, and other closely related signalling networks.     

可调控表达人博卡病毒1型非结构蛋白NS1稳定细胞系的建立及其反式转录激活作用初探

人博卡病毒1型(Human bocavirus 1,HBoV1)非结构蛋白NS1是多功能蛋白,对病毒复制有重要作用,同时可诱导宿主细胞凋亡。在研究NS1蛋白功能时,降低NS1蛋白对宿主细胞的毒性作用是急需解决的问题。基于此,文中建立了可调控表达HBoV1非结构蛋白NS1的稳定细胞系。构建NS1重组慢病毒质粒(含可调控启动子),应用转染试剂将NS1重组慢病毒质粒转染至HEK293T细胞。通过嘌呤霉素筛选抗性细胞、多西环素诱导NS1表达,建立可稳定表达NS1-100、NS1-70蛋白的HEK 293T细胞系,利用荧光标记蛋白和Western blotting检测,确定NS1蛋白的表达。并在稳定表达NS1细胞系中转染HBoV1启动子-荧光素酶基因的质粒,分析NS1的反式转录激活活性。结果表明NS1蛋白可在建立的细胞系中稳定表达,且稳定表达NS1蛋白对HBoV1启动子有较强的激活活性,为进一步研究非结构蛋白NS1的功能及人博卡病毒致病机理奠定了良好的基础。     

Establishment of human embryonic stem cell line stably expressing Epstein-Barr virus-encoded nuclear antigen 1

Human embryonic stem (hES) cells have the capability of unlimited undifferentiated proliferation, yet maintain the potential to form perhaps any cell type in the body. Based on the high efficiency of the Epstein-Barr virus-based episomal vector in introducing exogenous genes of interest into mammalian cells, we applied this system to hES cells, expecting that this would resolve the problem of poor transfection efficiency existing in current hES cell research. Therefore, the first step was to establish EBNA1-positive hES cells. Using the Fugene 6 transfection reagent, we transfected hES cells with the EBNA1 expression vector and subsequently generated hES cell clones that stably expressed EBNA1 under drug selection. These clones were confirmed to express EBNA1 mRNA by RT-PCR and to express EBNA1 protein by Western blotting. Furthermore, luciferase reporter gene analysis was performed on the EBNA1 clones and revealed that the expressed EBNA1 protein was functional. When the EBNA1-positive cells were injected into severe combined immunodeficient (SCID) mice, they formed teratoma tissues containing all three embryonic germ layers and EBNA1 protein was detected in these teratoma tissues by Western blotting. All the results show that we have successfully created stable EBNAI-hES cells, thus laying a good foundation for further research.     

人GLP-1R基因转染BHK细胞及重组细胞的应用

为了构建表达人胰高血糖素样肽-1受体(GLP-1R)基因的BHK细胞株,并利用该重组细胞对GLP-1等相关肽进行活性测定,首先通过酶切、连接方式将人GLP-1R基因克隆至真核表达载体pCDNA3.(1 )中,然后用脂质体转染法将重组质粒转染至BHK-21细胞,转染后的细胞经G418加压筛选、细胞有限稀释等方法获得克隆细胞株。经过该细胞株RT-PCR验证,结果证实目的基因已整合至BHK-21细胞基因组中,并获得成功转录和表达。活性检测实验表明该重组细胞株经过GLP-1的刺激后,其细胞中的cAMP含量得到明显提升。该细胞株的构建为GLP-1及相关肽的活性测定奠定了基础。     

Transfection of embryonal carcinoma cells at high efficiency using liposome-mediated transfection

Embryonal carcinoma (EC) cells are recognized as an excellent model system for studying the early stages of mammalian development. Many studies performed with EC cells involve transient transfection with promoter/reporter gene constructs and/or mammalian expression vectors. One of the limitations of working with EC cells is their inability to be transfected at high efficiency. In most cases, EC cells are transfected using the calcium phosphate method. The objective of this study was to identify protocols and culture conditions that significantly increase the transfection efficiency of EC cells. F9 EC cells were used for this purpose, because they are the EC cell line studied most commonly. We show that the transfection efficiency of F9 EC cells using the calcium phosphate method is less than 5%; whereas, their transfection efficiency can be improved approximately 15-fold using optimized culture conditions and liposome-based transfection reagents. Specifically, we demonstrate that more than 50% of F9 EC cells can be transfected using LipofectAMINE 2000. In addition to higher levels of transfection, there is much less plate-to-plate variation with liposome-based reagents as compared to transfection with calcium phosphate. Interestingly, transfection efficiency using these reagents was found to be inversely related to cell density. This contrasts sharply with the recommendation that transfection with LipofectAMINE 2000 or LipofectAMINE in conjunction with the PLUS reagent be performed at high cell densities. Given the improvements in transfection efficiency reported here, it will now be possible to perform studies with F9 EC cells that require transfection at significantly higher levels than that achieved using the calcium phosphate method. Overall, the highest transfection efficiencies were consistently obtained using LipofectAMINE 2000.