Construction and identification of eukaryotic eukaryotic expression plasmid pcdna3.1-bace and its transient expression in cells

Objective： To generate eukaryotic expression vector of pcDNA3.1-BACE and obtain its transient expression in COS-7 cells and high expression in the neuroblastoma SK-N-SH cells. Methods： A 1503 bp cDNA fragment was amplified from the total RNA of human neuroblastoma by RT-PCR method and cloned into plasmid pcDNA3.1. The vector was identified by digestion with restriction enzymes BamHI and XhoI and sequenced by Sanger-dideoxy：mediated chain termination. The expression of BACE gene was detected by immunocytochemistry method. Results： The results showed that the cDNA fragment included 1503 bp total coding region. The recombinant eukaryotic cell expression vector of pcDNA3.1-BACE was constructed successfully, and the sequence of insert was identical to the published sequence. The COS-7 cells and the neuroblastoma SK-N-SH cells transfected with the pcDNA3.1-BACE plasmid expressed high level of BACE protein in cytoplasm. Conclusion： The recombinant plasmid pcDNA3.1-BACE can provide very useful tool for researching the mason of Alzheimer＇s disease and lays the important foundation for preventing the AD laterly.     

Construction of Recombinant Adenovirus Carrying GRIM19 and Its Effect on SW480 Cells

In order to examine the effect of GRIM19 on colon cancer cell SW480, the recombinant adenovirus carrying GRIM19 gene was constructed and transfected into SW480 cells. GRIM19 cDNA was amplified by PCR with the template pcxn2-GRIM19 and cloned into the shuttle plasmid pAdTrack-CMV. The plasmid pAdTrack-CMV-GRIM19 was linearized by PmeⅠ and homologously recombined with bone plasmid pAdEasy-1 in BJ5183, followed by identification by enzyme digestion. After transfection of linearized pAd-GRIM19 with PacⅠ into HEK293 cells, Ad-GRIM19 was obtained and amplified by 3 circles. SW480 cells were infected with Ad-GRIM19. The apoptosis rate was detected by flow cytometry. Agarose electrophoresis revealed the bands of recombinant plasmids identified by enzyme digestion were in the right range corresponding with expectation. Under the fluorescent microscopy, the package of Ad-GRIM19 in HEK293 cells and the expression of Ad-GRIM19 in SW480 cells were observed. The transfection of Ad-GRIM19 into SW480 cells increased the apoptosis rate of SW480 cells as compared with controls, It was concluded that Ad-GRIM19 was successfully constructed and the overexpression of GRIM19 in colon cancer cell lines could promote the apoptotic cell death.     

Construction of Eukaryotic Expression Plasmid pcDNA3-FHIT and Its Transient Expression in COS-1 Cells

Objective: To construct eukaryotic expression plasmid pcDNA3-fragile histidine triad(FHIT) and obtain its transient expression in COS-1 cells. Methods: FHIT gene was cloned from normal human thyroid tissue by RT-PCR and then inserted into eukaryotic expression vector pcDNA3. After the sequence was confirmed, the recombinant plasmid pcDNA3-FHIT was transfected into COS-1 cells by cation liposome. The transient expression in the cells was measured by immunocytochemistry. Results: The sequence of FHIT in pcDNA3 was correct and high expression was obtained in COS-1 cells. Conclusion: The eukaryotic expression plasmid pcDNA3-FHIT was constructed successfully and could highly express FHIT protein in COS-1 cells. This will be potentially useful for the research on gene therapy.     

Construction of Smac gene-carrying and human uroplakin Ib promoter-Regulated Genetic Vector and its Expression

Objective： To construct an eukaryotic expression vector that contains Smac gene, which is regulated by human Uroplakin Ib （UpIb） promoter. Methods： For the directionality of Smac expression in the transitional cell carcinoma of bladder, internal CMV and T7 promoter sequences in eukaryotic expression vector pcDNA3.1-Smac were replaced with UpIb promoter to construct a new plasmid. The plasmid DNA was identified by gel electrophoresis after being double digested at respective sites, and then the sequence was analyzed. The expression of Smac mRNA and protein in BIU87 cell line were detected after the transfection by using the newly constructed vector. Results： The Smac gene-carrying and UpIb promoter-regulated eukaryotic expression vector pcDNA3-UpIb-promoter-Smac was successfully constructed. The expression of Smac mRNA was approximately increased by 2.1 times and the expression of Smac protein was increased in about 71% BIU87 cells. Conclusion： The new vector can be effectively expressed in bladder cancer cells and be of great significance for bladder cancer-targeted gene therapy.     

Construction of eukaryotic expression plasmid of hTGF-β3 and its inducing effect on differentiation of precartilaginous stem cells into chondroblasts

This study examined the construction of eukaryotic expression plasmid of human transforming growth factor-β3(hTGF-β3) and its inducing effect on the differentiation of precartilaginous stem cells(PSCs) into chondroblasts.hTGF-β3 gene was amplified by using polymerase chain reaction(PCR) and then inserted into the eukaryotic expression plasmid pcDNA3.1 to construct the eukaryotic expression plasmid pcDNA3.1(+)-hTGF-β3.Rat PSCs were isolated and purified by employing an immunomagnetic cell sorting system.pcDNA3.1(+)-hTGF-β3 was transfected into purified PSCs with the use of linear polyamines.The expression of TGF-β3 and cartilage-specific extracellular matrix(ECM) components was detected after transfection by real-time quantitative PCR,ELISA,immunochemistry and Western blotting,respectively.The results showed that the eukaryotic expression plasmid pcDNA3.1(+)-hTGF-β3 was successfully established as identified by enzyme digestion and DNA sequencing.Real-time quantitative PCR and ELISA revealed that hTGF-β3 was strongly expressed in pcDNA3.1(+)-hTGF-β3-transfected PSCs.Real-time quantitative PCR,immunochemistry and Western blotting showed that the cartilage-specific ECM markers,i.e.,cartilage oligomeric matrix protein(COMP),Aggrecan,collagen type Ⅹ and Ⅱ were intensely expressed in the pcDNA3.1(+)-hTGF-β3transfected cells.It was concluded that hTGF-β3 could be stably expressed in pcDNA3.1(+)-hTGFβ3-transfected PSCs and induce the differentiation of PSCs into chondroblasts.     

Inhibitory Activity of Nuclear Factor-κB Potentiates Cisplatin-induced Apoptosis in A549 Cells

Whether inhibiting the activity of nuclear factor(NF)-κB potentiates cisplatin-induced apoptosis in non-small cell lung cell line A549 cells was investigated.The recombinant plasmid pcDNA3.1( )/IκBα expressing IκBα was constructed.The in vitro cultured A549 cells were transfected with pcDNA3.1( )/IκBα alone,or pcDNA3.1( )/IκBα combined with cisplatin.The mito-chondrial membrane potential(?ψm) was determined by rhodamine 123,the activity of caspase-3 was tested by colorimetric assay,and cell apoptosis was detected by flow cytometry with the annexin Ⅴ/propidium iodide assay.The results showed that the activity of NF-κΒ in A549 cells was inhibited by transfecting pcDNA3.1( )/IκΒα.Transfection of pcDNA3.1( )/IκΒα alone did not promote apoptosis.Treatment of cisplatin alone had a little effect on cell apoptosis.Transfection of pcDNA3.1( )/IκΒα combined with cisplatin treatment significantly induced apoptosis of A549 cells.It was concluded that inhibiting the activity of NF-κB potentiated cisplatin-induced apoptosis of A549 cells.     

Effects of eukaryotic expression plasmid encoding human tumstatin gene on endothelial cells in vitro

Background Tumstatin is a novel endogenous angiogenesis inhibitor which is widely studied using purified protein.The current study evaluates the antiangiogenic effects of tumstatin-overexpression plasmid in vitro, reveals the mechanism underlying the vascular endothelial cell growth inhibition and searches for a novel method administering tumstatin persistently.Methods The eukaryotic expression plasmid pcDNA-tumstatin encoding tumstatin gene was constructed and transfected to human umbilical vein endothelial cell ECV304 and human renal carcinoma cell ACHN.Expression of tumstatin in the two cell lines was determined by RT-PCR and Western blotting.Vascular endothelial cell proliferation was assessed by CCK-8 assay and cell cycle was analyzed by flow cytometry.To investigate the mechanism by which pcDNA-tumstatin inhibited vascular endothelial cell proliferation in vitro, cyclin D1 protein was detected by Western blotting.Results DNA sequence confirmed that pcDNA-tumstatin was successfully constructed.RT-PCR and Western blotting indicated that tumstatin could express in the two cell lines effectively.After tumstatin gene transfer, ECV304 cell growth was significantly inhibited and the cell cycle was arrested in G1 phase.And Western blotting showed that pcDNA-tumstatin decreased the level of cyclin D1 protein.Conclusions Overexpression of tumstatin mediated by pcDNA 3.1 （＋） specially inhibited vascular endothelial cells by arresting vascular endothelial cell in G1 phase resulting from downregulation of cyclin D1 and administration of tumstatin using a gene therapy might be a novel strategy for cancer therapy.     

CONSTRUCTION AND IMMUNOGENICITY OF HUMAN PAPILLOMAVIRUS TYPE 6B L1 RECOMBINANT PLASMID

Objective To construct a DNA vaccine as a prophylactic model to prevent condyloma acuminatum and detect its immunogenicity in mice. Methods The major capsid protein (L1) gene of human papillomavirus (HPV) 6b was inserted into an eukaryotic expression plasmid (pcDNA3.1). The recombinant plasmid was transfected into COS-7 cells. Western blot were performed to detect whether L1 protein can be expressed in eukaryotic cells. Eighteen female BALB/c mice were tested for immunogenicity study. Results The recombinant plasmid (pcDNA3. 1-HPV6bL1) was verified as HPV6b L1 gene by sequencing. Western blot showed specific strip. Anti-L1 protein antibodies could be detected in the mice‘s sera inoculated with pcDNA3.1-HPV6bL1. Similarly, IL-4, IL-2, and IFN-γ were increased in the same mice. Conclusion HPV6b L1 recombinant plasmid was constructed successfully which had immunogenicity for BALB/c mice. It provided experimental evidence for the research of DNA vaccine of condyloma acuminata.     

核基质蛋白SAFB真核表达载体的构建及其鉴定

目的构建人SAFB基因真核表达载体,为SAFB基因功能研究提供研究基础。方法设计人SAFB特异性引物,提取人正常结直肠上皮组织总RNA,应用RT-PCR方法提取人SAFBcDNA,通过双酶切及测序鉴定,将SAFB克隆至pcDNA3.1（-）,构建人SAFB基因的真核表达载体pcDNA3.1（-）/SAFB,转染SW480细胞,用WesternBlot技术检测目的蛋白的表达。结果成功扩增人SAFB全长cDNA,双酶切鉴定和测序结果证实成功构建pcDNA3.1（-）/SAFB真核表达载体,转染细胞后,可检测出分子量约为140KD的目的蛋白。结论获得人SAFB基因全长cDNA并成功构建了SAFB真核表达载体,证实pcDNA3.1（-）/SAFB转染SW480细胞后可表达SAFB蛋白,为深入研究SAFB基因在肿瘤发生发展中的作用提供了基础。     

THY1基因对上皮性卵巢癌细胞SKOV3生长的抑制作用

目的 构建THY1真核表达质粒,并探讨THY1基因对上皮性卵巢癌细胞系SKOV3生长的影响.方法 通过RT-PCR方法,从人正常卵巢组织中获得THY1基因,将其插入真核表达质粒pcDNA3.1( )中,构建成重组质粒pcDNA3.1( )-THY1,并转入大肠杆菌JM109,筛选出含有正确插入片段的克隆,经PCR、酶切及DNA测序鉴定;脂质体介导法转染SKOV3细胞并筛选稳定表达(SKOV3-THY1组),同时设空质粒转染组(SKOV3-Null组)和空白对照组(SKOV3组),RT-PCR和Western blotting鉴定重组质粒的表达情况;MTT法和流式细胞术检测THy1对SKOV3细胞生长和凋亡等生物学行为的影响.结果 经过PCR、酶切及DNA测序证实,外源性THY1基因正确插入到真核表达质粒pcD-NA3.1( )中,RT-PCR和western blotting证实此重组质粒已整合于SKOV3细胞并获稳定表达;MTT法结果提示SKOV3-THYl组的细胞抑制率(第5天的细胞抑制率为56.6%)明显高于SKOV3-Null组(12.5%)(P＜0.05);流式细胞术检测结果显示,SKOV3-THY1组凋亡率(31.8%)明显高于SKOV3-Null组(10.5%)和SKOv3组(9.8%),差异有统计学意义(P＜0.05),SKOV3-Null组和SKOV3组间差异无统计学意义(P＞0.05).结论 成功构建了THY1真核表达质粒pcDNA3.1( )-THY1,该质粒转染SKOv3细胞可抑制其生长,THY1基因可能在上皮性卵巢癌发生、发展的过程中起重要作用.     

补体应答基因-32过表达对SW480细胞骨架的影响

摘要：目的通过基因重组技术构建pcDNA3.0-RGC32重组质粒,并检测其对细胞骨架的影响。方法扩增RGC32的全长
并定向克隆到真核表达载体pcDNA3.0,获得重组质粒pcDNA3.0-RGC32,转染SW480 细胞,采用G418 筛选单克隆,
Western blot检测转染前后SW480细胞中RGC32的表达水平,并制作转染前后SW480细胞骨架标本,并采用划痕实验观
察细胞的迁移能力。结果pcDNA3.0-RGC32真核表达载体构建成功,转染重组载体后细胞中RGC32的表达量明显增
多。转染重组质粒前,SW480细胞骨架中微丝纤维束少而短、极性不明显;转染重组载体后的细胞微丝纤维束数量增多,变
长,有了明显的极性,并且可见细胞膜向前伸出丝状结构的伪足或者是片状结构的伪足,细胞骨架发生了重组,并且过表达
后细胞的迁移能力增强。结论通过过表达RGC32,促进细胞骨架重组,有利于细胞运动,推测细胞骨架重组是RGC32促
进肿瘤转移的重要机制。     

miR-26a靶向HMGA1基因对结肠癌细胞生长、侵袭和迁移的影响

目的：探讨miR-26a靶向高迁移率族蛋白1（HMGA1）基因对结肠癌细胞生长、侵袭和迁移的影响,阐明HMGA1基因是否为miR-26a的靶基因。方法：将miR-NC （对照）、miR-26a mimics （模拟物）和miR-26a inhibitor （抑制物）转染人结肠癌SW480细胞作为miR-NC组、miR-26a mimics组和miR-26a inhibitor组。RT-PCR和Western blotting法分别检测各组SW480细胞中HMGA1 mRNA和蛋白表达水平。采用荧光素酶报告基因检测试剂盒检测各组SW480细胞中双荧光素酶活性,以此确定HMGA1是否为miR-26a的靶基因。采用CCK8实验检测各组细胞增殖活力,Transwell小室法检测各组细胞侵袭数和迁移数。结果：HMGA1基因是miR-26a的靶基因。与miR-NC组比较,转染24、48和72 h时miR-26a mimics组SW480细胞增殖活力明显降低（P<0.01）,而miR-26a inhibitor组细胞增殖活力明显升高（P<0.01）。与miR-NC组比较,各时间点miR-26a mimics组和miR-26a mimics+pcDNA3.1-HMGA1组细胞增殖活力、细胞侵袭数和细胞迁移数均降低（P<0.01）,而miR-NC+pcDNA3.1-HMGA1组细胞增殖活力、细胞侵袭数和细胞迁移数均升高（P<0.01）;与miR-26a mimics组比较,各时间点miR-26a mimics+pcDNA3.1-HMGA1组细胞增殖活力、细胞侵袭数和细胞迁移数均升高（P<0.01）;与miR-NC+pcDNA3.1-HMGA1组比较,各时间点miR-26a+pcDNA3.1-HMGA1组细胞增殖活力、细胞侵袭数和细胞迁移数均降低（P<0.01）。结论：HMGA1是miR-26a的靶基因。上调miR-26a表达可抑制人结肠癌SW480细胞增殖,下调miR-26a表达可促进人结肠癌SW480细胞增殖。     

抑癌基因PTEN真核表达载体的构建及对人卵巢癌细胞系SW626增殖的影响

目的 构建抑癌基因PTEN的真核表达载体,研究外源性PTEN基因稳定表达对人卵巢癌细胞系SW626体外增殖的影响.方法 构建PTEN基因的真核表达载体pcDNA3.1/PTEN,转染重组质粒pcDNA3.1/PTEN于体外培养的人卵巢癌细胞系SW626,筛选并获得稳定表达PTEN基因的细胞克隆,应用RT-PCR和western blot分析PTEN基因的mRNA及蛋白质表达,MTT实验分析细胞增殖能力.结果 稳定转染PTEN基因的细胞系有外源目的 基因的mRNA及其蛋白表达.MTT实验表明,pcDNA3.1/PTEN 转染组细胞增殖能力低于pcDNA3.1(-)转染组和对照组 (P＜0.05).结论 外源性抑癌基因PTEN的稳定表达可抑制人卵巢癌细胞系SW626的增殖.     

JAB1对缺氧环境肺癌A549细胞化疗敏感性调控的研究

目的观察导入pcDNA3.1-HRE-JAB1真核表达质粒的肺癌A549细胞,在低氧环境下对健择(Gemzar)的化疗敏感性,以期找到一种提高肺癌化疗敏感性的方法。方法首先构建缺氧反应元件启动的pcDNA3.1-HRE-JAB1真核表达质粒,鉴定后将该质粒导入肺癌A549细胞。在低氧环境培养过程中加入化疗药物Gemzar,观察空白组(A549)、空载体组(A549+pcD-NA3.1-HRE)和质粒组(A549+pcDNA3.1-HRE-JAB1)肺癌A549细胞对Gemzar的敏感性。采用Real-time PCR和Westernblot分别检测各组肺癌A549细胞中JAB1的mRNA和蛋白表达水平;流式细胞术检测各组肺癌A549细胞周期分布和凋亡情况。结果通过双酶切鉴定,确定构建获得了pcDNA3.1-HRE-JAB1质粒。在有化疗药物Gemzar的情况下,质粒组分别与空白组或空载体组比较,质粒组肺癌A549细胞中JAB1mRNA和蛋白表达水平明显增加(P<0.01),细胞凋亡率明显增加(P<0.01),而细胞周期被明显阻滞于G1期(P<0.01)。结论 JAB1在低氧环境下高表达提高了药物Gemzar化疗的敏感性,这将可能成为一种理想的提高肺癌或其他实体恶性肿瘤化疗敏感性的手段。     

靶向性双自杀基因治疗载体pcDNA3.1(-)Cp-CD-TK构建的初步研究

目的 构建由癌胚抗原启动子(CEA promoter,Cp)驱动的靶向性双自杀基因治疗载体pcDNA3.1(-)Cp-CD-TK,并观察其在CEA阳性大肠癌细胞中专一性表达和对增殖的影响.方法 采用PCR分别扩增出Cp、CD、TK三种目的 基因并采用双酶切、连接依次将Cp、CD、TK基因插入pcDNA3.1(-)质粒;将靶向性载体pcDNA3.1(-)Cp-CD-TK分别转染CEA阳性的人大肠癌SW480细胞和CEA阴性的Hela细胞,采用RT-PCR检测CD-TK基因的表达.用MTT法检测转染pcDNA3.1(-)Cp-CD-TK后的SW480细胞对化疗前药5-氟胞嘧啶(5-Fc)和丙氧鸟苷(GCV)的敏感性.结果 Cp基因片段、CD基因片段和TK基因均克隆正确.靶向性基因治疗载体pcDNA3.1(-)Cp-CD-TK经凝胶电泳和DNA测序证实构建正确.转染了靶向性载体pcDNA3.1(-)Cp-CD-TK的SW480细胞经过RT-PCR鉴定证实有CD-TK基因的表达,CEA阴性Hela细胞则没有CD-TK基因的表达.细胞培养试验中,转染了靶向性载体pcDNA3.1(-)Cp-CD-TK的SW480细胞对前药5-Fc和GCV敏感.结论 正确构建了靶向性双自杀基因治疗载体pcDNA3.1(-)Cp-CD-TK,靶向性双自杀基因治疗载体pcDNA3.1(-)Cp-CD-TK能够使CD-TK基因在CEA阳性细胞中专一性表达,达到靶向杀伤大肠癌细胞目的 .     

梅毒螺旋体外膜蛋白Gpd在Hela细胞中的表达及鉴定

目的 构建梅毒螺旋体（Tp）外膜蛋白甘油磷酸二酯磷酸二酯酶基因（Gpd）的真核表达载体peDNA3．1（＋）-Gpd，鉴定其在Hela细胞的表达，为开展TpDNA疫苗动物实验打下基础。方法 用PCR从TpNichols株基因组中扩增Gpd基因，构建真核表达重组质粒pcDNA3．1（＋）-Gpd，脂质体介导转染入Hela细胞，以免疫组化及跳tern-blot检测在Hela细胞中的表达。结果 双酶切及DNA测序显示重组质粒含有1059bp的目的基因片段，读码框架正确，无突变。该重组质粒在Hela细胞能有效表达分子量为41kDa的目的蛋白，重组蛋白能-9梅毒螺旋体阳性血清反应。结论 构建的质粒peD-NA3．1（＋）-Gpd成功地在体外真核细胞中表达。     

人大肠癌线粒体DNA重组质粒的构建

目的了解大肠癌细胞株（SW480，LoVo，HT29）线粒体DNA的突变，克隆突变的大肠癌线粒体DNA（mtDNA）基因，构建pcDNA3．1（＋）-mtDNA真核表达重组体，并导入NIH3T3细胞，以探讨线粒体基因突变与肿瘤发生的关系。方法提取大肠癌细胞株（SW480，LoVo，HT29）mtDNA，扩增D-LOOP区，产物用DNA自动测序法进行序列分析。利用DNA重组技术将其定向插人真核表达质粒pcDNA3．1（＋），并用脂质体法导人NIH3T3细胞。结果检测出大肠癌细胞株SW480、LoVo、HT29细胞mtDNAD—LOOP分别有10、9、8个突变位点。成功克隆1119bp的mtDNAD—LOOP区至表达质粒pcDNA3．1（＋），并导入NIH3T3细胞中。结论线粒体DNAD-LOOP区是一个具有高度多态性和突变性的区域，在大肠癌细胞株中突变率较高。     

人大肠癌线粒体DNA重组质粒的构建

目的 了解大肠癌细胞株(SW480,LoVo,HT29)线粒体DNA的突变,克隆突变的大肠癌线粒体DNA(mtDNA)基因,构建pcDNA3.I(+)-mtDNA真核表达重组体,并导入NIH3T3细胞,以探讨线粒体基因突变与肿瘤发生的关系。方法 提取大肠癌细胞株(SW480,LoVo,HT29)mtDNA,扩增D-LOOP区,产物用DNA自动测序法进行序列分析。利用DNA重组技术将其定向插人真核表达质粒pcDNA3.1(+),并用脂质体法导人NIH3T3细胞。结果 检测出大肠癌细胞株SW480、LoVo、HT29细胞mtDNAD-LOOP分别有10、9、8个突变位点。成功克隆1119bp的mtDNAD-LOOP区至表达质粒pcDNA3.1(+),并导入NIH3T3细胞中。结论 线粒体DNAD-LOOP区是一个具有高度多态性和突变性的区域,在大肠癌细胞株中突变率较高。