The Construction and Identification of Eukaryotic Expression Vector pEGFP-N1-hTERT

[Objective] The aim of this study is to construct eukaryotic expression vector pEGFP-N1-hTERT and observe its expression in eukaryotic cells.[Method]The eukaryotic expression vector pEGFP-N1-hTERT was constructed with pC1-neo-hTERT and pEGFP-N1 plasmids,and the accuracy of human telomerase reverse transcriptase(hTERT)gene fragment was confirmed by double enzyme digestion and DNA sequencing analysis.After transfecting pEGFP-N1-hTERT into rat fetal neural stem cells(NSCs),the protein localization of human telomerase reverse transcriptase were indirectly observed through green fluorescent protein in the cells,and the correctness of constructed pEGFP-N1-hTERT was certificated by RT-PCR and Western Blot analysis.[Result]The eukaryotic expression vector pEGFP-N1-hTERT had correct structure and could express in eukaryotic cells.[Conclusion]This study laid a foundation for the establishment of immortalized NSCs line in rats.

Construction and Expression of Sugarcane UGPase cDNA Prokaryotic Expression Vector

UGPase （UDP-glucose pyrophosphorylase）, one of the primary enzymes concerned with carbohydrate metabolism, catalyzes the formation of UDPG. By inserting the UGPase cDNA fragment cloned from Saccharum officinarum into PQE-30, the prokaryotic expression vector of PQE-UGP was successfully constructed. Then the vector plasmid of PQE-UGP was transformed into host bacteria M 15 and the expression of target gene was induced by Isopropyl β-D-1-Thiogalactopyranoside （IPTG）. The research laid foundation for study on the prokaryotic expression of UGPase.

Overexpression of the mTERT gene by adenoviral vectors promotes the proliferation of neuronal stem cells in vitro and stimulates neurogenesis in the hippocampus of mice

We sought to construct the adenoviral vector carrying the gene encoding mouse telomerase reverse transcriptase（mTERT）,as well as detect its expression and effect on the proliferation of neuronal stem cells.mTERT was am-plified by RT-PCR and then the eukaryotic expression vector of pDC-EGFP-TERT was constructed.After DNA sequence analysis,we detected that there were 293 cells transfected with pDC-EGFP-TERT and helper adenovirus plasmid pBHG lox ΔE1,and three Cre using Lipofectamine 2000 mediation,named Ad-mTERT-GFP,to pack-age adenoviral particles.The Ad-mTERT-GFP was used to infect neuronal stem cells and then the expression and activity of mTERT were detected.In addition,Bromodeoxyuridine labeling test identified the impact of mTERT overexpression on proliferation of neuronal stem cells.The recombinant adenoviral vector confirmed that mTERT was successfully constructed.Overexpression of mTERT stimulated the proliferation of neuronal stem cells both in vitro and in vivo.mTERT overexpression via adenoviral vector carrying mTERT cDNA upregulated the ability of proliferation in neuronal stem cells.

Prokaryotic expression of recombinant human p75NTR-Fc fusion protein and its effect on the neurite outgrowth of dorsal root ganglia neuron

Objective： To clone, express, and identify the extracellular domain gene of human p75 neurotrophin receptor with IgG-Fe （hp75NTR-Fc） in prokaryotic expression system, and investigate the effect of the recombinant protein on dorsal root ganglia （DRG） neuron neurites. Methods： The hp75NTR-Fc coding sequence was amplified from pcDNA-hp75NTR-Fc by polymerase chain reaction （PCR） and subcloned into vector pET30a （＋）, in which hp75NTR-Fc expression was controlled under the T7 promoter. The recombinant vectors were amplified in E. coli DH5α and identified by PCR, enzyme digestion and sequencing, and then transformed into E. coli BL21 （DE3）. The expression product was analyzed with SDS-PAGE and Western blot. Then after the recombinant protein purified with Protein A affinity chromatograph, and renaturated with dialysis, respectively, the effect of the recombinant protein on DRG neuron neuritis was further investigated. Results： The results of PCR, enzyme digestion, and sequencing demonstrated the success of inserting the hp75NTR-Fc fragment into vector pET30a （＋）. SDS-PAGE and Western blot showed a positive protein band with molecular weight about 50 kD in the expression product, which is accordant with the interest protein, and this band could be specifically recognized by rabbit anti-NGFRp75 antibody. The purified infusion protein following dialysis could promote neurite outgrowth of DRG neurons cultured with myelin-associated glycoprotein （MAG）. Conclusion： The hp75NTR-Fc coding sequence was subcloned into the expression vector pET30a （＋） correctly and expressed successfully in the prokaryotie expression system. The infusion protein could promote neurite outgrowth of DRG neurons cultured with MAG.

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

Construction of the pIRES2-ZsGreen1 eukaryotic expression vector of factor Ⅸ gene and expression in HEK-293 cells

Objective To construct p IRES2-ZsG reen1/FⅨexpression vector,using the pcDNA/FⅨplasmid containing FⅨcDNA as template,and expressing in HEK-293cells.Methods The total ORF of FⅨgene was amlified from pcDNA/FⅨplasmid,then the amplified fragment was clonded into the p IRES2-ZsG reen1 vector using

小鼠SGK3真核表达载体的构建及鉴定

目的构建含有小鼠血清和糖皮质激素诱导蛋白激酶3(serum and glucocorticoid-induced protein kinase 3,SGK3)基因的真核表达载体pcDNA3.1-MYC-SGK3-mCherry,并观察和验证其在转染细胞HEK293中的表达。方法通过聚合酶链式反应将实验室保存的真核表达质粒pcDNA3.1-MYC-SGK3中目的基因SGK3与mCherry融合并扩增出来,然后定向克隆至pcDNA3.1-MYC质粒中,经限制性内切酶消化和测序证实后,通过脂质体法转染HEK293细胞,Western blotting法检测目的基因的蛋白表达情况。结果测序结果与之前预期结果相符,证实pcDNA3.1-MYC-SGK3-mCherry真核表达载体构建成功。Western blotting结果显示,转染pcDNA3.1-MYC-SGK3-mCherry的HEK293细胞出现清晰的阳性反应条带,说明目的片段成功表达。结论pcDNA3.1-MYC-SGK3-mCherry真核表达载体构建成功。

TFAP2A基因重组真核表达载体的构建及鉴定

目的构建转录因子增强子结合蛋白-2α的真核表达载体并进行鉴定,为TFAP2A的后续研究提供有效工具。方法采用限制性内切酶BamHⅠ和HindⅢ对真核表达载体CV702质粒进行酶切获得线性化载体;通过PCR扩增制备TFAP2A的cDNA片段,将线性化载体和TFAP2A的cDNA扩增产物进行体外环化连接,构建CV702-TFAP2A重组质粒。将连接产物进行细菌转化,挑取平板上的单克隆进行PCR鉴定,对阳性克隆进行测序及结果分析。将CV702-TFAP2A重组真核表达载体转染乳腺癌细胞MDA-MB-231,通过Western blot检测TFAP2A的表达效率。结果菌落PCR扩增和测序结果显示,CV702-TFAP2A重组真核表达载体构建成功;Western blot结果与Image J灰度值分析结果显示,与CV702对照载体相比,转染CV702-TFAP2A重组质粒的MDA-MB-231中的Flag-TFAP2A蛋白相对表达量更高(P<0.05)。结论成功构建CV702-TFAP2A的重组真核表达载体,证实转染CV702-TFAP2A的细胞中Flag-TFAP2A的表达水平升高。

一种载体构建的新方法:重组融合PCR法

本研究介绍一种多目的片段一步重组克隆的载体构建的新方法。该方法要求在PCR引物设计时,在第一个目的片段上游引物的5'端和最后一个目的片段下游引物的5'端各设置16bp与线性化目标载体末端同源的序列,再在各目的片段之间的引物上各设计25bp的重叠序列,以便进行融合PCR将多片段扩增成融合片段。此方法将融合片段与线性化骨架载体进行一步重组、转化和重组子鉴定。该方法只要求骨架载体上有一个特异性酶切位点,特别适用于插入片段中含有较多限制性酶切位点的载体构建;该方法还可以引入定点突变,可便捷构建分析启动子功能等需引入定点突变的载体;该构建方法还可以实现多基因的无缝融合构建多顺反子,在构建原核基因表达载体、叶绿体表达载体、线粒体表达载体方面有着明显优势。本研究以水稻胚乳特异性表达载体PGt1-mGFP-pSB130为例,介绍此载体构建方法。

抗菌肽Japonicin II基因真核表达载体的构建

采用SOE法人工设计和合成抗菌肽Japonicin II基因。按正确的阅读框架定向克隆至真核表达载体pPICZαA上,经PCR鉴定及序列分析,所转化的毕赤酵母GS115中含有插入Japonicin II基因的重组质粒pPICZαA-Jap,结果表明成功构建了抗菌肽JaponicinII基因真核表达载体pPICZαA-Jap。

毛竹PsbS基因的克隆及其原核表达特征研究

采用RT-PCR技术从毛竹(Phyllostachys edulis)叶片中克隆到1个PsbS基因,命名为PePsbS(GenBank No.FJ600727),其编码区为810 bp,编码269个氨基酸。序列分析表明,PePsbS编码的蛋白与其它单子叶植物的PsbS蛋白有很高的相似性。蛋白结构分析表明,PePsbS基因编码蛋白包含导肽部分和成熟蛋白,其中成熟蛋白包含4个跨膜结构域。将PePsbS基因编码成熟蛋白的序列构建到原核表达载体pET23a中,并转入大肠杆菌,用IPTG进行诱导表达。结果表明,41℃下诱导4 h的表达效果最好,目的蛋白含量约占总蛋白的21.5%,分子量约为22.0 kD。这说明温度和诱导时间明显影响PePsbS基因的表达。

中华大蟾蜍galectin-3 cDNA的克隆、序列分析及原核表达载体的构建

通过PCR扩增出中华大蟾蜍Bufo gargarizans半乳糖凝聚素3(gal-3)cDNA全长开放读码框(ORF)并克隆至pGM-T载体,经DNA测序确定获得全长ORF序列(GenBank登录号为JN993733).序列分析表明中华大蟾蜍gal-3的ORF是由789个碱基组成,编码262个氨基酸残基组成的蛋白质.推导氨基酸序列同源性比较发现,中华大蟾蜍与非洲爪蟾Xenopus lavis同源性最高,为51%,与其他10种动物的同源性在41%～50%之间.SMART分析显示gal-3蛋白在136-259位氨基酸存在保守的半乳糖结合域.Net Phos预测gal-3在Ser-6和Ser-186有潜在的丝氨酸磷酸化位点.gal-3氨基酸序列构建的进化树符合传统动物分类学特点.经菌落PCR、双酶切和DNA测序确认gal-3的ORF正确插入原核表达载体pET-28b,表明原核表达用重组质粒构建成功,为研究其蛋白功能和生物学功能奠定了基础.

r-PA真核表达载体的构建与鉴定

用SV40和CaMV35S两种启动子分别启动瑞替普酶(reteplase,rPA)和标记基因bar基因,构建能在海带中表达外源基因的重组表达载体。通过PCR方法扩增CaMV35S启动子、bar基因和rPA基因,将扩增的3个片段分别克隆到pGEMTEasyVector上。将CaMV片段亚克隆到pCAT3control载体上得到重组质粒pCAT/CaMV;再将bar基因切下插入到CAT/CaMV上得到重组质粒pCAT/CB,最后将rPA基因片段切下后插入到pCAT/CB上获得重组质粒pSVrPA/CB。PCR、酶切及测序结果均表明已成功扩增出CaMV35S、rPA和bar基因片段,并已顺次正确插入到真核表达载体PCAT3control上,最终成功构建了能在海带中表达rPA的真核表达载体,用基因枪法转入海带中表达,FAPA法测定得到有体外纤溶活性的阳性海带,为后续研究工作打下坚实的基础。

犬细小病毒VP_2基因原核表达载体的构建与分析

从犬细小病毒/犬瘟热进口二联苗中提取犬细小病毒基因组DNA,以此为模板进行PCR扩增,PCR产物经BamH I和XhoI双酶切后,克隆至pET22b(+)质粒的相应位点上,构建了原核表达载体pET22b/VP2.重组质粒经限制性内切酶酶切和核苷酸序列分析表明,VP2基因已正确克隆到pET22b(+)载体上,从而成功地构建了pET22b/VP2表达载体.

大豆GmERF6基因的原核表达及重组蛋白纯化

将大豆中已克隆的一个新的ERF转录因子基因(GmERF6)构建到原核表达载体pET28上,导入大肠杆菌Rosetta(DE3)中,对其进行IPTG诱导。结果表明:在IPTG浓度为0.3 mol.L-1,诱导时间为3 h时,重组蛋白得到表达,分子量大约为30 kDa。SDS-PAGE电泳结果表明重组蛋白主要以包涵体形式存在。用8 mol.L-1尿素对其进行溶解后经Ni柱纯化,得到较好的纯化效果,Bradford法测定其蛋白浓度为0.56 mg.mL-1。

DsRED红色荧光蛋白植物表达载体的构建和表达

为获得红色荧光蛋白(Red fluorescent protein,RFP)真核表达载体35S-pC1301-DsRED,利用PCR将瞬时表达载体PGDR上的全长DsRED扩增下来并用XbaⅠ和BamHⅠ酶切该片段,同时用相同的内切酶消化中间载体pBluescript SK(+),连接两片段并测序,将鉴定正确的DsRED用相同的内切酶切下并导入双元载体35S-pC1301,利用基因枪将正确质粒转染洋葱内表皮细胞瞬时表达DsRED。结果表明:35S-pC1301-DsRED真核表达载体已成功构建并在荧光共聚焦显微镜下呈现红光,即获得了可产生红色荧光的35S-pC1301-DsRED载体,为今后植物目的基因定位提供了阳性对照,同时中间载体pBluescript SK(+)-DsRED的构建为今后植物目的基因定位提供了实验工具。

胃黏膜特异表达JC病毒T抗原质粒构建及表达鉴定

目的利用鼠胃黏膜上皮细胞中高活性的角蛋白19(K19)启动子构建K19-JCVT抗原表达质粒并进行鉴定。方法利用PCR方法突变JC病毒T抗原中的NdeⅠ位点,并在两端插入BclⅠ位点,通过BamHⅠ位点将DNA片段与K19启动子连接,构建K19-JCVT抗原质粒。利用酶切和DNA测序确认其DNA序列。免疫组化筛选细胞角蛋白19阳性胃癌细胞,对细胞角蛋白19表达阳性的胃癌细胞系AGS进行K19-JCVT抗原质粒转染,用Western blot方法检测JCVT抗原的表达情况。结果K19-JCVT抗原表达质粒成功构建,AGS胃癌细胞系高表达细胞角蛋白19并用于K19-JCVT抗原表达质粒转染,转染K19-T抗原质粒的AGS细胞系有T抗原表达。结论同义突变和相似连接在质粒构建中起到关键作用,酶切位点的甲基化也是值得注意的问题。

人反义VEGF基因表达载体的构建及其对卵巢癌细胞增殖的影响

目的 :构建人反义VEGF基因真核表达载体 ,进行抗血管生成治疗卵巢癌实验。方法 :RT PCR法获得人VEGF基因 ,将VEGF基因反向克隆入真核表达载体pcDNA3中 ,酶切鉴定结果。用此真核表达载体转染人卵巢癌细胞HO 8910 ,G418筛选获得阳性克隆 ,RNA斑点杂交鉴定HO 8910细胞中VEGF表达。Westernblot及间接免疫荧光法检测转染前后HO 8910细胞中VEGF蛋白表达。检测转染前后瘤细胞的生物学性状及裸鼠体内致瘤性。结果 :RT PCR法得到VEGF基因 ,并获得反向构建的VEGF真核表达载体。VEGF反义RNA部分阻断了HO 8910细胞中VEGF表达 ,转染后单个细胞的克隆形成能力明显减弱 ;细胞周期中 ,G1期细胞增多 ,S期细胞减少 ,细胞增殖能力降低 ;形态学超微结构显示细胞器扩张和肿胀 ,核染色质边集 ,凝集成块 ,可见明显的凋亡改变。裸鼠体内致瘤性降低。结论 :成功构建了反义VEGF基因真核表达载体 ,该载体可明显抑制卵巢癌细胞增殖 。