欢迎订阅2006年下列期刊

AIM: To construct prokaryotic expression vector of His-tagged human IP-10 for further study of its biological function in the inflammatory response. METHODS: The coding sequence of IP-10 lacking signal peptide was amplified from human lung cDNA library by polymerase chain reaction (PCR) and the fragment was cloned into pET-14b plasmid for the construction of His-tagged fusion protein expressing vector, pET-14b/IP-10. After being identified by enzyme digestion and sequencing, the recombinant vector was transformed into a strain of E. coli, BL21 (DE3). The expression of His-tagged fusion protein was induced with IPTG and purified with Ni+-NTA affinity chromatography. Then the chemotactic activity of IP-10 was determined by transwell migration assay on THP-1 cells. RESULTS: The construction of pET-14b/IP-10 recombinant vector was proved by enzyme digestion and sequencing. The fusion protein IP-10, which was purified by a routine Ni+ affinity method, had an activity on the induction of cell migration of THP-1. CONCLUSION: We successfully construct IP-10 fusion protein expressing vector and get the fusion protein with high bioactivity, which provides essential materials for the future studies on IP-10. V     

Prokaryotic expression and preparation of GST/BFRF3 fusion protein of Epstein-Barr virus for screening nasopharyngeal carcinomas

AIM: To construct a prokaryotic expression plasmid containing Epstein-Barr viral (EBV) capsid antigen BFRF3 gene and to observe the application of recombinant BFRF3 protein in the serological diagnosis of nasopharyngeal carcinoma (NPC).METHODS: DNA extracted from the B95-8 cells was used as the templates. Polymerase chain reaction (PCR) was used to generate a DNA fragment of BFRF3 gene, and a 531-bp DNA fragment was inserted into a PGEX-5X-1 vector. The recombinant plasmid was transformed into E.coli BL21 (DE3). The expression of GST/BFRF3 fusion protein was induced by IPTG, identified by both SDS-PAGE and Western blotting, and then purified by glutathione-sepharose beads. The purified recombinant protein was coated to microplate for ELISA detection of EBV-IgA antibody in NPC patients.RESULTS: The GST/BFRF3 fusion protein was successfully expressed in E. coli. The molecular weight of the product was approximately 44 kD. The recombinant fusion protein GST/BFRF3 showed good immunoreactivity. A novel ELISA was established using GST/BFRF3 protein. Serum samples collected from the NPC patients and healthy controls were tested by this ELISA. The sensitivity and specificity of GST/BFRF3 tests for NPC patients were 65％ and 87％, respectively.CONCLUSION: The recombinant protein GST/BFRF3 is expressed in E.coli, and it has diagnostic value for screening of NPC patients.     

Cloning of hCD154 gene from human activated peripheral blood mononuclear cell and expression of hCD154-GST fusion protein in prokaryote

AIM:To express recombinant hCD154-GST fusion protein, to prepare anti-hCD154 monoclonal antibody, and to investigate the effect of anti-hCD154 monoclonal antibody on graft rejection. METHODS AND RESULTS: Total RNA was prepared from human peripheral blood mononuclear cell (PBMC) activated with 10ng/mL PMA and 1 μg/mL PHA for 8h, the total RNA was reversetranscribed to cDNA. The entire coding region and a part of the 3'non-coding regions were amplified by PCR using a pair of primers designed and synthesized according to the sequence of human CD154 gene from gene bank. The amplified product, a 820bp DNA fragment was cloned into pGEX-4T-1 plasmid expressing glutathione S-transferase(GST). The cloned insert was identified by double digestion of the cloned pGEX-4T-1 plasmid with retriction enzymes BamHⅠand EcoRⅠ.The fusion protein expression plasmid of PGEX-4T-1/hCD154 was constructed, then transformed to E coli BL21. The human CD154-GST fusion protein expression was induced by IPTG in BL21. The expression of recombinant 26kD GST and 55kD human CD154-GST fusion protein were confirmed by SDS-PAGE. CONCLUSION: We have express the recombinant human CD154-GST fusion protein. The expressed hCD154-GST fusion protein will be used to prepare anti-hCD154 monoclonal antibody, to investigate the role of anti-CD154 monoclonal antibody on graft rejection.     

Preparation and characterization of anti-hBLyS monoclonal antibody by DNA immunization

AIM:To establish the monoclonal antibody against human B lymphocyte stimulator (hBLyS) by DNA immunization and analyse its characterization. METHODS:The 858 bp DNA fragment of hBLyS was cloned into pcDNA3 plasmids. The cloned insert was identified by both sequence analysis and double digestion of the recombinant plasmid with restriction enzymesXho Iand EcoR I. After the splenocytes from BALB/c mice immunized with the recombinant plasmid of pcDNA3/hBLyS were fused with myeloma cells SP2/0,the hybridoma which can produce monoclonal antibodies against hBLyS were obtained. The specificity of anti-BLyS monoclonal antibody from hybridoma was verified by ELISA, Western blot and flow cytometry. RESULTS:The recombinant mammalian cell expression vector of pcDNA3/hBLyS was constructed,the sequence of the insert gene was identified to be the sequence encoding hBLy S antigen. The culture supernatants of hybridoma 9c10 were tested to be the monoclonal antibody with specificity against hBLyS on human peripheral blood CD3⁺T cell activated by hIFN-γ by ELISA,Western blot and flow cytometry.CONCLUSION:The monoclonal antibodies against hBLyS with high activity and specificity have been established successfully, and will be an useful tool in the studies of relationship between hBLyS and human autoimmunity diseases.     

番木瓜环斑病毒外壳蛋白基因原核表达蛋白的抗血清制备及其检测应用

 以受番木瓜环斑病毒（Papaya ring spot virus,PRSV）侵染的番木瓜（Carica papaya）叶片为供试材料,采用RT-PCR 方法克隆其外壳蛋白基因cp,并将其连接到原核表达载体pET-28b（+）上,酶切鉴定及克隆测序确定开放阅读框的正确性,将获得的重组质粒转化大肠杆菌表达宿主菌。通过摸索转化的表达宿主菌种类、IPTG 浓度及诱导时间,获得高效表达PRSV cp 的条件。SDS-PAGE 分析结果表明,CP 融合蛋白分子量为36.8 kD。以Ni2+-NTA 亲和层析柱纯化的融合蛋白为抗原,免疫注射新西兰大白兔制备得到高效价抗体,间接ELISA 测定效价为1︰16 384。Western blot 检测结果表明,制备的抗血清可与诱导表达的融合蛋白发生特异性反应。通过ID-ELISA 检测田间样品证实了制备的抗血清与PRSV 侵染病叶发生了良好的特异性反应。本试验为PRSV 的快速检测以及PRSV 编码蛋白的功能研究奠定了基础。     

马铃薯卷叶病毒缺失突变CP基因的原核表达及抗血清的制备

 利用RT-PCR扩增马铃薯卷叶病毒（PLRV）外壳蛋白（CP）基因（PLRV-CP）,回收大小约630 bp的特异性扩增片段并进行T-A克隆,测序表明该基因长度为627 bp,与已报道的36个PLRV-CP基因的核苷酸序列的同源性大于96%。以pBAD/Thio-TOPO为起始载体,构建了PLRV-CP基因的原核表达载体pBAD-LRCP。以pBAD-LRCP为模板,用PCR法删除了该基因富含精氨酸稀有密码子的第52 ~ 177核苷酸,获得了PLRV缺失突变CP基因的原核表达载体pBAD-LRCP-126。用阿拉伯糖诱导工程菌TOP10（pBAD-LRCP-126）,获得了34 kD的诱导表达的融合蛋白（重组CP）。用镍离子亲和层析法从包涵体中纯化出了高纯度的重组CP,用纯化的重组CP作抗原免疫家兔获得了PLRV特异性的抗血清,间接ELISA检测显示效价为1︰12 800。本研究结果为利用重组CP作抗原大量制备PLRV抗血清奠定了基础。     

Construction of prokaryotic expression vector of human angiogenesis inhibitor arresten and its expression in E.coli

AIM:To construct prokaryotic expression vector of human angiogenesis inhibitor arresten gene and express recombinant arresten in Escherichia coli.METHODS:Human arresten gene was amplified from recombinant plasmid pGEM-Arr with polymerase chain reaction (PCR), and then cloned into prokaryotic expression vector pRSET by means of recombinant gene technology. The recombinant plasmid pRSET-Arr was transformed into E.coli BL21(DE3), and recombinant arresten was expressed in the bacteria under induction of IPTG. The expressed products were detected by SDS-PAGE analysis.RESULTS:Restriction analysis indicated that the arresten gene was successfully inserted into the expression vector, and DNA sequencing verified that the reading frame of the recombinant vector was correct. Recombinant arresten was successfully expressed in Escherichia coli; its molecular weight was about 26 kD and its amount was approximately 30% of total bacterial proteins.CONCLUSION:The successful construction of prokaryotic expression vector containing human arresten gene and the effective expression of recombinant arresten in Escherichia coli laid the foundation for further study on its biological functions.     

Cloning and expression of NK4 gene in Raji cells

AIM: To clone NK4 gene and to construct recombinant eukaryotic expression vector for observing its expression in transfected Raji cells. METHODS: Total RNA was extracted from human hepatic tissue. NK4 gene cDNA was amplified by RT-PCR, and then cloned into vector pVITRO2-mcs to construct the recombinant eukaryotic expression vector pVITRO2-mcs-NK4. Raji cells were transfected by recombinant vector pVITRO2-mcs-NK4 and screened by homomycin B. The stable strain of NK4 gene expression was screened by real-time fluorescent quantitative PCR, ELISA, immunocytohistochemistry and semisolid culture. RESULTS: The specific DNA fragment was detected by RT-PCR in Raji cells transfected with NK4 gene. The transfected Raji cells expressed NK4 mRNA and protein stably, which inhibited Raji cell proliferation, metastasis and invasion. CONCLUSION: NK4 gene is cloned and recombined to construct recombinant eukaryotic expression vector pVITRO2-mcs-NK4 successfully. NK4 gene in Raji cells expresses stably.     

苹果AFS基因的克隆与原核表达

 通过RT-PCR扩增到苹果α - 法尼烯合成酶(α-Farnesene Synthase, AFS) 基因的编码区全长,将其克隆到pET-30a ( + ) 上, 构建了该基因的原核表达载体pET-AFS, 转化大肠杆菌BL21。SDS2PAGE检测结果表明, 此基因表达了1个约66 kD的蛋白, 1 mmol/L异丙基-β - D - 硫代半乳糖苷( IPTG) 诱导该基因高效表达, 6 h表达量最高, 诱导产物以包涵体形式存在。     

Cloning of human sperm protein(SP17) and expression in escherichia coli DH5α

AIM: To obtain GST fusion protein of hSP17 gene and construct the recombinant plasmidfor expression in E.coli.METHODS:Total fragment of hS P17 cDNA gene were amplified by RT-PCR,then subcoloned into p GEX-3b to generate recombinant hS P17/pGEX.Right orientation of insert are identified by restricted enzyme digestion.Transform the correct recombinant plasmid into the E.coli DH5a.The expression of fusion proteins hS P17-GST were induced by adding isopropylthiogalactoside(IPTG).RESUL TS and CONCLUSION:The recombinant plasmid hS P17/pGEX-3b could express effectively in E.coli and a high level of fusion protein hsp17-GST with the predicted molecular weight was detected.     

Prokaryotic expression of Staphylococcus aureus Panton-Valentine leukocidin and its cytolytic activities to human polymorphonuclear neutrophils

AIM:Panton-Valentine leukocidin (PVL) is a pore-forming toxin secreted by Staphylococcus aureus epidemiologically associated with the often-lethal necrotizing pneumonia. Until now, the mechanisms of pathogenesis of PVL leading to the fatal pulmonia remains undefined and also acquired plenty of the toxins is difficult. In the present study, we obtain recombinant staphylococcal F and S components of the Panton-Valentine leukocidin by gene engineering and evaluate its biological activity in vitro, which provides an experimental basis for the further studies of its biological function and its toxicity in pneumonia. METHODS:The full-length of F and S components of PVL gene amplified from the strain of Staphylococcus aureus DNA by high-fidelity PCR was cloned into prokaryotic expression vector pET22b(+), and the vector was transformed into BL21 (DE3)plysS to construct a prokaryotic expression system. The integrity of the opening-reading frame of each construct was verified by DNA sequencing. The recombinant PVL (rPVL) was induced by1.0 mmol/L IPTG. The expressed products were identified by SDS-PAGE and the fusion proteins (6His-LukS-PV and 6His-LukF-PV) were purified from lysates of transfected E. coli cells by affinity chromatography on nitrilotriacetic acid columns. The cytolytic activity was tested by incubation of rPVL with human polymorphonuclear neutrophils (PMNs) in vitro. RESULTS:The nucleotide sequence of the cloned PVL gene was the same as that of reported in GenBank. E. coli BL21 (DE3)plysS containing recombinant vectors grow at 37℃ causes some proteins to accumulate as inclusion bodies, while incubation at 30 ℃ led to a significant amount of soluble active proteins which accounted for about 31.7% of the total bacterial protein.The relative molecular weight showed on SDS-PAGE profile was consistent with the expected value which the LukS-PV protein was about 34 kD, and the LukF-PV protein was about 35 kD. The purified rPVL was obtained and its cytolytic activity to PMNs was demonstrated. CONCLUSION:The genes of lukS-PV and lukF-PV are successfully cloned into plasmid pET22b(+) and expressed in E. coli respectively, which provide a basis for analyzing the toxicity related to the diseases and further studies about the pathogenesis of PVL.     

苹果MxIrt1基因的克隆与原核表达

根据植物IRT(Iron Regulated Transporter)家族的功能保守区设计引物,通过RACE法从缺铁胁迫处理的小金海棠根系cDNA文库中克隆得到了Fe²⁺转运蛋白基因cDNA全长,将其命名为MxIrt1(Malus xiaojinensis Iron regulated transporter 1)。将MxIrt1 cDNA片段与pET30a构建原核表达载体pEIrt,转化大肠杆菌BL21。SDS-PAGE电泳检测结果表明,以30℃、0.5mmol·L^-1 IPTG诱导该基因表达效果最好,诱导产物为一个40kD的蛋白。为进一步纯化和鉴定目的蛋白提供了试验基础。     

罗汉果葡萄糖基转移酶基因的克隆及原核表达

 从罗汉果（Siraitia grosvenorii）转录组中获得一条与罗汉果甜苷Ⅴ生物合成相关的葡萄糖基转移酶（UDPG）的unigene片段,以罗汉果授粉后70 d的果实RNA为模板,利用RACE和RT-PCR技术克隆UDPG全长基因,将克隆得到的SgUDPG1基因连接到原核表达载体pEASY-E1上,构建融合表达载体,转化到大肠杆菌BL21（DE3）,通过IPTG诱导表达,重组蛋白纯化,SDS-PAGE检测表达产物以及Western-blotting和质谱鉴定蛋白产物。结果表明,获得了1条SgUDPG1,全长为1 959 bp,开放阅读框ORF为1 365 bp,编码1条454 aa的肽链,理论分子量为51.2 kD,等电点为5.39,具有植物中次生代谢产物糖基转移酶特有的保守结构域PSPG-box motif。SgUDPG1在授粉后50 d和70 d的果实中表达逐渐升高,是对照授粉后3 d的5.16倍和13.12倍,与果实中甜苷Ⅴ含量呈相同趋势。此基因的ORF可以在大肠杆菌中表达,并且可以纯化出比理论分子量大5.3 kD的融合蛋白,通过Western-blotting和质谱鉴定,确定该蛋白属于罗汉果葡萄糖基转移酶。     

High efficient expression of human endostatin in E.coli and its antiangiogensis activity

AIM: To examine the expression of human endostatin in E.coli, produce its fusion protein antibody and observe its biological activity. METHODS: Endostatin gene was amplified by polymerase chain reaction,recombined with plasmid vector pGEX-2T and induced expression with IPTG.The protein activity was tested by endothelial cell proliferation inhibitory assay.Inclusion body crudely purified was used to generate polyclonal antibody to detect its expression at mouse's liver and kidney etc. RESULTS: The protein expressed was 20kD after digestion by thrombin,it appeared the anti-angiogenesis activity and Western blotting indicated the expression of endostatin in liver and kidney of mouse. CONCLUSION: The successful expression of human endostatin and the preparation of polycolonal antibody indicated its potential application in anti-angiogenesis therapy and diagnosis tumors.     

Construction of mouse pdx-1 gene eukaryotic expression vector and its expression in embryonic stem cells

AIM: To clone mouse pdx-1 gene and construct its eukaryotic expression vector for expression of pdx-1 in mouse embryonic stem cells.METHODS: Mouse pdx-1 cDNA fragment was amplified with polymerase chain reaction (PCR) from mouse pancreatic cDNA. The purified fragment was recombinated with a eukaryotic expression vector carrying enhanced green fluorescent protein, pEGFP-N1. The pdx-1 cDNA fragment was inserted into the multi-clone sites of the vector to construct a new plasmid, pEGFP/pdx-1. E.colli strain DH5α was transfected with the new recombinant plasmid to expand it. Plasmid DNA extracted from the expanded DH5α was identifed by cutting with Hind Ⅲ, BamHⅠ nuclease and by DNA sequencing. Identified plasmid DNA was transfected into mouse embryonic stem cell line MESPU13 by carrying with liposome. RESULTS: A 876 bp cDNA fragment was amplified from mouse pancreatic cDNA by PCR and it was inserted into the vector pEGFP-N1 correctly. The fragment was defined to be pdx-1 gene by nuclease digestion and DNA sequencing. Mouse embryonic stem cell line MESPU13 was transfected with the new recombinant plasmid DNA. The green fluorescent protein report gene and pdx-1 gene expressed in transfected mouse embryonic stem cells within 24 h. CONCLUSION: Mouse pdx-1 gene is cloned and its recombinant eukaryotic expression vector carrying green fluorescent protein is constructed successfully. It provides a useful tool for further research on the function of pdx-1.     

Construction of human anti-HBc ScFv eukaryotic expression vector and expression of anti-HBc ScFv in HepG2 cells

AIM: To construct an eukaryotic expression vector of human single-chain variable fragment against hepatitis B virus core protein (anti-HBc ScFv) and detect its expression in HepG2 cells. METHODS: Anti-HBc ScFv genes were amplified from the plasmids abstracted from positive clone and inserted into pEGFP-c1 vector that contained green fluorescent protein gene. The recombinant plasmids were transfected into HepG2 cells, and resistant clones were obtained by G418 selection. The expression of the gene of fusion protein was determined by fluorescent invert microscope and ELISA. RESULTS: Recombinant plasmids were successfully constructed. The plasmid transfected HepG2 cells were obtained by G418 selection. Specific fluorescence was observed in HepG2 cells 48 hours after transfection. ELISA analysis confirmed the expression of anti-HBc ScFv in the cells. CONCLUSION: The construction of human anti-HBc ScFv eukaryotic expression vector and its expression in HepG2 cells lay the foundation for advanced research of intracellular anti-HBc ScFv.     

High and stable expression of an analog of human basic fibroblast growth factor in Escherichia coli

AIM: To obtain a high and stable expression analog of human basic fibroblast growth factor by genetic engineering. METHODS: The cysteins 78 and 96 of natural hbFGF polypeptide was substituted with serines by means of site-directed mutagenesis. Using pET-3c as vector, the mutated polynucleotide was cloned and then transferred into BL21 (DE3) plysS. After induction by IPTG, the analog was obtained and analyzed by SDS-PAGE. RESULTS: After purification the form of soluble mutant increased remarkably but the forms of dimmer and higher multimer were reduced greatly to no more than 8% of the total recombinant protein. By MTT assay, the analog showed the same biological activity. This new analog represented a desirable complementation for native hbFGF to develop pharmaceutical drug in clinical use. CONCLUSION: Substitution of certain amino acids of polypeptide without altering native protein's bioactivity to get the analog is an effective means to increase stability of foreign protein and its solubility in E.coli.     

香蕉果实转录因子MaWRKY1基因的原核表达和多克隆抗体制备

MaWRKY1是从香蕉果实中克隆出的一个转录因子基因。为进一步研究该基因的功能,制备了MaWRKY1多克隆抗体。选取MaWRKY1基因全长中N端第168 ~ 400个氨基酸之间的包括两个WRKYGQK保守域的cDNA序列,构建了原核表达载体pET-MaWRKY1,并转化到大肠杆菌BL21中诱导表达菌体蛋白。SDS-PAGE电泳检测结果表明,His-MaWRKY1融合蛋白成功获得了高效表达,分子量在26 kD左右。His-MaWRKY1融合蛋白经过Ni-NTA琼脂糖凝胶树脂纯化,SDS-PAGE制备胶割胶富集,电洗脱法纯化后得到的纯化蛋白浓度达到0.5 mg • mL-1。经对新西兰兔进行5次免疫,获得了多克隆抗血清,采用免疫吸附方法对抗血清进行了纯化。将纯化后的抗体通过间接酶联免疫（ELISA）和蛋白质印迹（Western blot）分析,表明所制备的抗体具有很好的效价,效价比为1︰160 000,同时具有良好的灵敏度和特异性。进一步提取香蕉不同组织总蛋白,Western blot检测显示,在分子量26 kD左右处出现特异的蛋白质条带,证明所制备的抗体可以与香蕉WRKY蛋白特异性结合,并且低温可以诱导香蕉果实中MaWRKY1蛋白表达,暗示MaWRKY1蛋白表达可能与果实耐冷性有一定的关系。     

瓜类褪绿黄化病毒p22 基因在大肠杆菌中的表达及抗血清的制备

 以被瓜类褪绿黄化病毒（Cucurbit chlorotic yellows virus,CCYV）侵染的甜瓜叶片为供试材 料,采用RT-PCR 方法克隆其P22 蛋白基因,并将其连接到原核表达载体pGex-4T-3 上,PCR 验证及克隆 测序确定开放阅读框的正确性。将重组载体pGexp22 转化大肠杆菌BL21 菌株,诱导表达,SDS-PAGE 分 析表明,经IPTG 诱导,p22 基因在大肠杆菌BL21 中得到了高效表达。以表达的蛋白作为抗原,免疫家 兔,制备了CCYV P22 的特异性抗血清。ACP-ELISA 检测结果表明,血清效价高达1.28 × 10⁵。Western blot 检测甜瓜叶片,结果表明抗血清能够特异性地检测CCYV 侵染的甜瓜叶片中的CCYV P22 蛋白。     

小菜蛾类钙粘蛋白片段的原核融合表达载体 构建及其条件优化

构建了小菜蛾钙粘蛋白片段基因的重组载体,为提高其在大肠杆菌中的表达量,研究了时间、
温度、IPTG 浓度对融合蛋白表达量以及可溶性的影响。结果表明,使用LB 培养基37 ℃培养1.5 h 后,采
用终浓度为0.1 mmol·L-1 的IPTG,在25 ℃ 180 r·min-1 诱导培养36 h 融合蛋白的表达量最大,并且温
度的改变对融合蛋白的可溶性几乎没有影响,SDS-PAGE 电泳检测结果表明,融合蛋白的分子质量与预计
大小一致,约为16 kDa。