2型登革病毒非结构蛋白NS3的表达及其相互作用蛋白的纯化

目的构建2型登革病毒(DENV2)非结构蛋白3(NS3)与亲和标签融合蛋白的表达质粒,串联亲和纯化(TAP)法获得与NS3相互作用的蛋白。方法根据DENV2基因序列,设计引物;以DENV2 c DNA为模板,PCR扩增出NS3基因,经酶切后克隆至含有串联亲和标签(FLAG-StrepⅡ)的哺乳真核表达载体p CI-SF,获得重组表达质粒p CI-NS3-SF;将上述重组质粒通过转染试剂LipofectamineTM2000瞬时转染进入HEK293T细胞,Western blot法验证NS3融合蛋白的表达;通过TAP法分离纯化与NS3相互作用的蛋白。结果成功构建了NS3融合蛋白表达载体,利用TAP系统分离得到与NS3蛋白相互作用的宿主蛋白。结论串联亲和纯化法可以有效的分离与DENV2 NS3相互作用的细胞蛋白。     

真核表达人呼吸道合胞病毒F蛋白的纯化方法

目的 真核表达人呼吸道合胞病毒(human respiratory syncytial virus,SV)融合蛋白(fusion protein,),并完成蛋白纯化及纯度测定.方法 根据编码F蛋白的基因序列设计引物,CR方法扩增出3'端带His标签的F基因序列,克隆入pGEM-T-easy载体,经核酸序列分析后,进一步克隆到pcDNA3.1( )真核表达载体,限制性内切酶鉴定,用脂质体Lipofectamine2000转染COS-7细胞,2 h后再用Westem blot检测目的蛋白的表达.Ni柱亲和层析纯化COS-7细胞表达的F蛋白,高效毛细管电泳分析纯化后蛋白纯度.结果 核酸序列分析证实获得带His标签的RSV F基因序列,没有发生无义突变.转染COS-7细胞后,利用Western blot方法检测到F蛋白的特异性条带,纯度达99%以上.结论 初步建立了真核表达RSV F蛋白的纯化方法,为进一步优化RSV F蛋白制备条件及单克隆抗体及诊断试剂等研究奠定了基础.     

人酪氨酸激酶6原核表达载体的构建、表达、纯化与鉴定

目的构建人络氨酸激酶6(PTK6)与His融合蛋白重组表达载体,在大肠杆菌中诱导表达,并对重组蛋白进行纯化。方法通过PCR在编码PTK6的cDNA序列两端添加EcoR I和BamH I酶切位点,双酶切后将编码PTK6的cDNA序列亚克隆至原核表达载体PHUE构建重组蛋白表达载体PHUE/PTK。重组载体经鉴定后转化大肠杆菌表达菌株BL21(DE3)感受态细胞。IPTG诱导重组蛋白表达。收集菌体裂解后,用尿素洗涤和溶解包涵体。溶解上清经Ni-NTA亲和层析柱纯化,并用SDS-PAGE和Western blotting检测纯化产物。结果成功构建人PTK6重组蛋白原核表达载体,重组蛋白以包涵体形式表达,其相对分子质量为55 000,与预期一致。亲和层析纯化产物的SDS-PAGE和Western blotting鉴定表明获得纯度大于80%的目的重组蛋白。结论人PTK6 His融合蛋白的纯化为多克隆及单克隆抗体的制备以及结构和功能的研究奠定了基础。     

带组氨酸标签的癌蛋白SET真核表达载体的构建及其表达

目的为研究三氯乙烯诱导的差异蛋白SET在肝细胞L-02中的相互作用,构建了癌蛋白SET和His标签融合表达的真核表达载体pcDNA3．1（＋）／SET—His。方法从L-02肝细胞中提取总RNA,采用RT-PCR扩增SET—His基因并进行双酶切,序列纯化后定向克隆至pcDNA3．1／zeo（＋）载体,阳性克隆载体进行双酶切和测序鉴定．阳性克隆载体瞬时转染入L-02肝细胞,利用Western blotting检测SET—His融合蛋白的表达。结果利用RT—PCR从L-02细胞总RNA中成功克隆出SET基因,经双酶切和测序鉴定证实pcDNA3．1（＋）／SET—His真核表达载体构建成功。经Western blotting验证表明,SET—His融合蛋白在肝细胞中获得高效表达。结论该结果为研究SET蛋白相互作用以及三氯乙烯致机体损伤的机理奠定了基础。     

人睾丸精子结合蛋白-His6融合蛋白在真核细胞中的表达及亲和纯化

目的:构建含有人睾丸精子结合蛋白基因(testisspermbindingprotein,tsbp)的真核表达载体pcDNA3.1/mycHis(-)B/tsbp,并进行表达和纯化。方法:以克隆有tsbp全长cDNA序列的原核表达载体pGEX5X1/tsbp为模板,用PCR扩增tsbp,并通过DNA重组构建真核表达载体pcDNA3.1/mycHis(-)B/tsbp。以重组体稳定转染HEK293细胞后,应用RTPCR、Westernblot和细胞免疫荧光技术检测His6tsbp融合蛋白的表达。选择高表达量的细胞克隆,扩增并用Ni2 NTA金属亲和层析柱(IMAC)从细胞裂解液中纯化融合蛋白His6tsbp,纯化产物的纯度用SDSPAGE和Westernblot进行鉴定。结果:成功地构建了真核表达载体pcDNA3.1/mycHis(-)B/tsbp。以重组体转染HEK293细胞后,用RTPCR检测到tsbpmRNA的表达。细胞免疫荧光染色呈阳性反应,Westernblot检测到培养细胞中有融合蛋白His6tsbp的表达。经Ni2 NTA金属亲和层析柱分离纯化,得到纯化的重组蛋白His6tsbp。结论:构建了pcDNA3.1/mycHis(-)B/tsbp真核表达载体,并在HEK293细胞中表达和亲和层析纯化,为下一步的研究奠定了基础。     

结核分枝杆菌脂蛋白G在HEK293T细胞中的表达及纯化

目的构建含结核分枝杆菌(MTB)脂蛋白G(Lpr G)基因的真核表达载体pc DNA3.1-His-Lpr G-FLAG,并在HEK293T细胞中表达和纯化Lpr G融合蛋白。方法以MTB H37Rv基因组DNA为模板,用PCR法扩增Lpr G基因,并通过DNA重组构建真核表达载体pc DNA3.1-His-Lpr G-FLAG,酶切鉴定并测序。将重组质粒转染HEK293T细胞后,应用Western blot法检测His-Lpr G-FLAG融合蛋白的表达。利用Ni-NTA金属亲和层析柱从细胞上清和细胞裂解液中纯化融合蛋白His-Lpr G-FLAG,并用SDS-PAGE和Western blot法检测纯化后的蛋白。结果成功构建了pc DNA3.1-His-Lpr G-FLAG的真核表达载体,Western blot结果表明转染质粒后,HEK293T细胞裂解液中检测到目的蛋白,相对分子量(Mr)为27 000。经Ni-NTA金属亲和层析柱纯化后得到高纯度的融合蛋白His-Lpr G-FLAG。结论成功构建并在HEK293T细胞中表达和纯化了His-Lpr G-FLAG融合蛋白。     

大鼠过氧化物酶体增生因子活化受体α基因重组腺病毒载体及在乳鼠心肌细胞中的表达

背景：过氧化物酶体增生因子活化受体α是调节心脏脂肪酸氧化的重要核转录因子,利用基因工程技术构建其重组腺病毒载体对研究心脏能量代谢障碍机制具有重要意义。 目的：构建大鼠过氧化物酶体增生因子活化受体α基因重组腺病毒载体,评价其在原代培养的乳鼠心肌细胞中的表达效率。 方法：采用RT-PCR法自SD大鼠肝脏扩增过氧化物酶体增生因子活化受体α基因,将其克隆至带有增强型绿色荧光蛋白的穿梭质粒载体pAd-Track-CMV。线性化重组穿梭质粒载体并转化入含有腺病毒骨架质粒pAd-Easy-1的感受态大肠杆菌BJ5183构建重组腺病毒载体质粒。用脂质体将线性化的重组腺病毒载体质粒转染于人胚肾293细胞以包装、扩增,纯化病毒后计算滴度。用纯化的重组腺病毒转染心肌细胞,荧光显微镜观察转染效率;荧光定量PCR、免疫印迹法检测细胞过氧化物酶体增生因子活化受体α mRNA、蛋白表达。 结果与结论：成功构建携带大鼠过氧化物酶体增生因子活化受体α基因的重组腺病毒载体,病毒滴度为3.5×10¹¹ pfu/L。重组腺病毒转染心肌细胞的效率达90%以上,被转染细胞目的基因mRNA、蛋白表达显著增高。该载体的成功构建为研究过氧化物酶体增生因子活化受体α基因在心肌能量代谢障碍中的作用奠定基础。     

hLKB1基因重组质粒构建及蛋白表达和定位

目的构建hLKB1真核表达载体,证实融合蛋白在胃癌细胞内的表达及定位。方法提取胃正常黏膜上皮细胞GES-1的总mRNA并进行反转录。以反转录的cDNA为模板PCR扩增hLKB1全长编码基因,克隆至pCDNA3.1/flag的真核表达载体中。将构建的重组质粒测序并转染到胃癌SGC-7901细胞中,分别利用Western blot和激光共聚焦扫描显微技术检测其表达和在胃癌细胞中的定位。结果 hLKB1全长基因序列克隆到真核表达载体中,酶切鉴定片段为1300bp。Western blot检测到真核转染的Flag-hLKB1在胃癌SGC-7901细胞表达,条带约为50kD,免疫荧光显示蛋白广泛定位于细胞质和细胞核内。结论成功构建了hLKB1基因真核表达载体,并验证其在胃癌细胞表达。     

Tat融合蛋白表达载体TAT-SOX2的克隆化及蛋白表达研究

目的 构建重组表达载体TAT-SOX2,在E.coli BL21中高效表达并纯化融合蛋白.方法 经PCR获得编码人SOX2的全基因序列,连接到原核表达载体PET-28b-TAT-V2上,得到重组表达载体TAT-SOX2,转化大肠埃希菌,IPTG诱导TAT-SOX2融合蛋白的表达.表达产物用SDS-PAGE鉴定,亲和层析柱纯化融合蛋白,并应用Western Blot检测蛋白的特异性,应用免疫荧光检测融合蛋白转导HSF细胞的效果.结果 成功构建了TAT-SOX2融合蛋白的原核表达载体,在诱导下获得了高效表达并纯化了融合蛋白,Western Blot鉴定正确.免疫荧光提示融合蛋白可快速转导入HSF细胞内.结论 为进一步的通过蛋白转导方式诱导多能干细胞提供了物质基础.     

人DRR1真核表达载体和稳定转染HEK293细胞株的建立及鉴定

目的:构建人DRR1基因的真核表达载体,通过转染HEK293细胞建立稳定的DRR1表达细胞株.方法:通过改造质粒pIRES,在其MCS1和MCS2中分别引入串联亲和纯化标签和绿色荧光蛋白基因,形成一个新的表达质粒pFSIG.将PCR扩增的DRRl1基因插入pFSIG中进行酶切和测序验证.用重组质粒pFSIG-DRR1转染HEK293细胞,通过G418和绿色荧光检测筛选DRR1稳定表达细胞株.通过Westernblot鉴定FS-DRR1蛋白的表达.结果:酶切、PCR和测序证实成功构建了pFSIG-DRR1表达质粒;建立了稳定转染的HEK293细胞系,Western blot检测证明重组DRR1在该细胞系中成功表达.结论:融合有串联亲和纯化标签的DRR1真核表达载体的构建和稳定表达细胞HEK293株的建立为在生理条件下研究DRR1的相互作用蛋白奠定了基础.     

重组人源抗HBsAg单链抗体的纯化及亲和常数测定

目的:对融合6×His标签的人源抗乙型肝炎表面抗原单链抗体的包涵体进行纯化和复性, 并对复性产物的抗原结合性质进行鉴定。方法:工程菌表达的包涵体裂解后, 金属螯合亲合层析纯化, 然后以尿素透析、盐酸胍透析和金属螯合亲和层析柱原位复性3种方法进行复性;复性产物以免疫亲和层析精制, 非竞争酶免疫法测定亲和常数结果:盐酸胍透析复性产物的比活性最高, 蛋白回收率为(61.08±1.45)%;精制后的重组单链抗体的亲和常数为(2.30±0.32)×10⁷L/mol.结论:本株单链抗体可以应用优化的透析复性技术, 在体外高效复性, 其抗原结合性质不受N末端纯化标签的影响。     

The trefoil peptide TFF1 inhibits the growth of the human gastric adenocarcinoma cell line AGS

TFF1 is a 60-amino acid peptide produced in normal gastric mucosa which forms dimers spontaneously. Tumours of patients with gastric cancer usually have reduced TFF1 levels and disruption of the TFF1 gene causes animals to develop gastric adenomas and carcinomas. The effect of normal sequence human recombinant TFF1 and an analogue (Cys⁵⁸→Ser⁵⁸), which is unable to dimerize, on the proliferation and morphology of the human gastric adenocarcinoma cell line AGS was therefore investigated. Proliferation, assessed by total cell number and [methyl-³H]thymidine incorporation, was reduced by dimeric TFF1 in a dose-dependent manner. Monomeric TFF1 also reduced proliferation but was less potent than the dimeric form. It is concluded that TFF1 may be an important controller of gastric cell proliferation, that dimerization of TFF1 is important in this effect, and that the reduced levels of TFF1 seen in gastric cancer may be of clinical relevance. Copyright © 1999 John Wiley & Sons, Ltd.     

Expression of recombinant West Nile virus prM protein fused to an affinity tag for use as a diagnostic antigen

Previous studies have concluded that the Flavivirus prM protein is a suitable viral antigen to distinguish serologically between infections with closely related Flaviviruses (Cardosa et al., 2002). To express the recombinant West Nile virus (WNV) prM antigen fused to a suitable affinity tag for purification, a series of prM-His-tag and prM-V5-tag fusion proteins were generated. Analysis of the prM-His-tag fusion proteins revealed that either prM epitopes were disrupted or the His-tag was not presented properly depending on the location of the His tag and the presence of the prM transmembrane domains in these constructs. This identified domains critical for proper folding of prM, and arrangements that allowed the correct presentation of the His-tag. However, the inclusion of the V5 epitope tag fused to the C terminus of prM allowed formation of the authentic antigenic structure of prM and the proper presentation of the V5 epitope. Capture of tagged recombinant WNV_NY99 prM antigen to the solid phase with anti-V5 antibody in ELISA enabled the detection of prM-specific antibodies in WNV_NY99-immune horse serum, confirming its potential as a useful diagnostic reagent.     

人CIDE-3基因原核表达载体的构建及蛋白的初步表达

目的:构建人CIDE-3基因的原核表达载体,并在E.coliBL21(DE3)中表达。方法:提取人肝母细胞瘤细胞系HepG2细胞的总RNA,经RT-PCR扩增人CIDE-3基因片段,并将其克隆入原核表达载体pET28a( )中,构建重组质粒pET28a( )-CIDE-3。经限制性内切酶BamHI、XhoI双酶切鉴定及序列测定后,转化E.coliBL21(DE3),经IPTG诱导表达组氨酸融合蛋白。结果:获得全长为516bp的人CIDE-3基因片段。以构建的重组质粒pET28a( )-CIDE-3转化E.coliBL21(DE3)后,经IPTG诱导,表达出相对分子质量(Mr)约为23000的重组CIDE-3蛋白。SDS-PAGE分析显示,表达的蛋白主要以不溶性包涵体的形式存在于E.coliBL21(DE3)的胞质中,表达量约占全菌蛋白的32%。结论:成功地构建了原核表达载体pET28a( )-CIDE-3,并表达出重组CIDE-3蛋白,为进一步多克隆抗体的制备和凋亡的相关研究奠定了实验基础。     

The scavenger receptor,cysteine-rich domain-containing molecule gp-340 is differentially regulated in epithelial cell lines by phorbol ester

Gp-340 is a glycoprotein belonging to the scavenger receptor cysteine rich (SRCR) group B family. It binds to host immune components such as lung surfactant protein D (SP-D). Recent studies found that gp-340 interacts directly with pathogenic microorganisms and induces their aggregation, suggesting its involvement in innate immunity. In order to investigate further its potential immune functions in the appropriate cell lines, the expression of gp-340 in four conventional immune cell lines (U937, HL60, Jurkat, Raji), and two innate immune-related epithelial cell lines (A549 derived from lung and AGS from stomach), was examined by RT-PCR and immunohistochemistry. The resting immune cell lines showed weak or no gp-340 mRNA expression; while the two epithelial cell lines expressed gp-340 at much higher level, which was differentially regulated by phorbol myristate acetate (PMA) treatment. In the A549 cells, gp-340 was up-regulated along with the PMA-induced proinflammatory expression of both IL-6 and IL-8. In AGS cells, PMA down-regulation of gp-340 was seen in parallel with an up-regulation of the two mature gastric epithelial specific proteins TFF1 (trefoil factor 1) and TFF2, which are implicated as markers of terminal differentiation. Analysis of the distribution of gp-340, together with the TFFs and SP-D in normal lung and gastric mucosa, supported further our in vitro data. We conclude that the differential regulation of gp-340 in the two epithelial cell lines by PMA indicates that gp-340 s involvement in mucosal defence and growth of epithelial cells may vary at different body locations and during different stages of epithelial differentiation.     

人重组IL-17/His蛋白的原核表达、纯化及其生物学活性

目的:研究人IL-17的体外生物学活性。方法:采用RT-PCR的方法克隆得到了hIL-17基因序列。将测序正确的人IL-17基因装入PQE3.0原核表达载体构建重组载体hIL-17/PQE3.0。该重组载体导入宿主菌M15,经异丙基β-D硫代半乳糖苷(IPTG)诱导产生IL-17/His融合蛋白,并经West-ernblot实验确认。结果:原核表达的hIL-17/His重组蛋白经变性、复性后,利用HiTrapTM亲和层析得到纯品蛋白。体外活性实验表明,该融合蛋白具有刺激人宫颈癌细胞株HeLa分泌IL-6和GM-CSF的作用。结论:制备了具有生物学活性的IL-17/His重组蛋白,为进一步研究该分子在自身免疫疾病等方面的作用奠定了基础。     

Dual expression of the HA protein of H5N2 avian influenza virus in a baculovirus system

Baculovirus/insect cell system is used widely for recombinant protein production. The hemagglutinin (HA) gene of H5N2 avian influenza virus (AIV) 1209 strain and the enhanced green fluorescent protein (EGFP) gene were cloned into pFastBac DUAL vector that has two promoters and cloning sites, allowing simultaneous expression of these two genes. The HA protein of AIV was fused with a hexahistidine (His6) tag for purification. The coexpression of EGFP allowed identification of the recombinant baculoviruses in Sf-9 insect cells, eliminating cumbersome and time-consuming assays. A recombinant baculovirus, Bac-HA, was generated by transfecting pBac-HA to bacmid inside DH10B(AC)Escherichia coli by site-specific transposition, followed by transfection into the Sf-9 cells. Fluorescence in the insect cells was observed from 3 days post-infection. The expressed HA protein was confirmed by Western blot using an anti-HA monoclonal antibody. Also, different detergents and incubation times on ice were tested. The two-stage extraction with Triton X-100 or Tween 20 and incubation on ice for 2h exhibited high efficiency. Since purification of HA with ConA resin resulted in low protein recovery, lentil lectin affinity column was used and was useful for HA purification.     

重组人抑癌相关蛋白核苷二磷酸激酶A的原核表达

目的:为提高表达量,简化纯化工艺,获得可用于临床研究的重组人NDPK-A蛋白,构建带有6×His纯化标签的原核表达载体,优化表达条件获得产物高表达并鉴定产物活性。方法:将抑癌基因nm23-H1 从质粒pBVNMH1中亚克隆于带有纯化标签的表达载体pQE40中;梯度变化表达条件获得产物高表达;镍离子螯合层析柱纯化目的蛋白;Western blot鉴定产物的免疫原性;HPLC测定产物的激酶活性;鸡胚尿囊膜试验鉴定产物抑制血管新生的生物活性。结果:pQE-40中亚克隆的nm23-H1 序列无误;目的蛋白最高表达量可达49.6%;纯化的表达产物能与天然NDPK－A的多克隆抗体特异结合;酶比活为472U/mg;具有抑制鸡胚尿囊膜血管新生的活性。结论:表达质粒pQE-nm23H 1 能高效表达重组人NDPK-A,纯化工艺简便,产物活性与天然NDPK-A无异。     

pNTAP-PRAK真核表达载体的构建及其在HEK293细胞中的表达

目的: 构建pNTAP-PRAK真核表达质粒,并建立其稳定表达的HEK293细胞系。方法: 将人的PRAK亚克隆至串联亲和纯化(tandem affinity purification, TAP)载体pNTAP质粒上,构建成重组质粒pNTAP-PRAK,转化该重组质粒至感受态大肠杆菌DH5α,阳性克隆进行PCR、酶切及DNA测序验证正确后,利用PolyFect脂质体介导将其转染至HEK293细胞中,再通过G418筛选建立稳定表达TAP tag-PRAK融合蛋白的HEK293细胞系;利用Western blotting和细胞免疫荧光标记法检测融合蛋白TAP tag-PRAK的表达及细胞内定位情况。结果: 重组真核表达载体构建正确,该重组质粒能在HEK293细胞中稳定表达,表达产物TAP tag-PRAK主要分布在核内。结论: 成功构建pNTAP-PRAK真核表达载体并建立了其稳定表达的HEK293细胞系,TAP标签未对PRAK定位产生明显影响。