Contruction of the Genetic Engineering Strain Expressed Nontoxic ST_1-LT_B Fusion Protein Against Enterotoxigenic Eschenichia coli

Thermostable enterotoxinⅠ(ST1) mutant genes and thermolabile enterotoxin B subunit (LTB)genes were amplified by PCR from plasmids of Eschenichia coli C83902. The recombinantexpression plasmid pZST3LTB containing ST1-LTB fusion gene was constructed by recombinantDNA technique and then transformed into Escherichia coli BL21(DE3). The ST1-LTB fusionprotein was highly expressed in recombinant strain BL21(DE3)(pZST3LTB) and the fusionprotein was about 38.53% of total cellular protein by SDS-PAGE and thin-layer gelscanning analysis. More important, mice immunized with crude preparation containing thefusion protein inclusion bodies or inactivated recombinant strain produced antibodiesthat were able to recognize ST1 in vitro. These sera antibodies were able to neutralizethe biological activity of native ST1 in the suckling mouse assay. Hence the ST1-LTBfusion protein was nontoxic and immunogenic, the constructed recombinant strain BL21(DE3)(pZST3LTB) could be used as a candidate of vaccine strain.

Cloned s-Lap Gene Coding Area, Expression and Localization of s-Lap/GFP Fusion Protein in Mammal Cells

s-Lap is a new gene sequence from pig retinal pigment epithelial(RPE) cells, which was found and cloned in the early period of apoptosis of RPE cells damaged with visible light. We cloned the coding area sequence of the novel gene of s-Lap and constructed its recombinant eukaryotic plasmid pcDNA3.1-GFP/s-lap with the recombinant DNA technique. The expression and localization of s-lap/GFP fusion protein in CHO and B_~16 cell lines were studied with the instantaneously transfected pcDNA3.1-GFP/s-lap recombinant plasmid. ~s-Lap/GFP fusion protein can be expressed in CHO and B_~16 cells with a high rate expression in the nuclei.

GST Fusion Protein Based Specific Polyclonal Antibody Preparation of Mouse Aquaporin 1

Aquaporins（AQPs） are specific membrane channels for water and other small nonionic molecules.In order to overcome the difficulties to generate the effictive antibody of membrane protein,we selected the cytoplasmic C-terminus of Aquaporin 1（AQP1） as an unique antigen.The long C-terminus of mouse AQP1 was overexpressed in the Glutathione S-tansferase Gene Fusion System.On the basis of the resonable amounts of soluable membrane protein peptides,we prepared the specific antibody.To pursure this object,we constructed pGEX-4T-1/mAQP1（DNA sequence from 700 to 801 bp） recombinant plasmid and transformed it into Escherichia coli BL21 cells.The GST-AQP1 C-terminal hydrophilic peptide fusion protein was induced by IPTG and further purified by Glutathione Sepharose 4B to obtain the right size fusion protein.Then we immunized the New Zealand rabbits to prepare the antiserum.The purified AQP1 antibody showed high sensitivity by ELISA assay and high specificity by Western blot with AQP1 null mice served as negative control.Finally,we also checked the AQP1 localization in the mouse renal tissues in wild type of mice and AQP1 null mice served as negative control.We demonstrated that AQP1 was highly expressed at the descending limb of Henle tube using our purified AQP1 antibody,which was consistent with previous report.The successful design and preparation of AQP1 antibody through GST technique is an example as making antibodies against a specific membrane protein.

Fusion of EGFP and porcine α 1,3GT genes decrease GFP expression

Objective:To investigate the effect of fusion proteins expressed by the fused gene of porcineα1,3 galactosyltransierase(α1,3 GT) and enhanced green fluorescent protein(EGFP) on the green fluorescence intensity of EGFP.Methods:The fragment containingα1.3GT was firstly recovered after the pcDNA3.1-α1.3GT recombinant vector were digested with BamHl and EcoRI,and then,the resultant fragment was ligated to the pEGFP-N1 vector which was also digested with the same enzymes.The new recombinant eukaryotic expression pEGFP/a 1,3GT vector was obtained and sequenced.The pEGFP/α1,3GT was used to transfect human lung carcinoma cells A549 and HEKC 293FT,and the expression of EGFP was quantitatively analyzed by fluorescent microscope and flow cytometry.Results:The positive percentage of A549 was 80.5%,and that of 293 FT was 86.5%48 hours after the two cell lines both were transfected by pEGFP-N1.The positive percentage of A549 was 75.8%,and that of 293 FT was 81.2%48 hours after the two cell lines were transfected by pEGFP/α1.3GT.The mean fluorescence intensities of A549 transfected with pEGFP-N1 and pEGFP/α1.3GT were 1.21 and 0.956,respectively when compared with that of A549 without transfection.Meanwhile,the those of the 293FT that were transfected with pEGFP-N1 and pEGFP/αl,3GT were 7.66 and 1.00.respectively when compared with that of 293FT cells without transfection.Conclusions:These results suggested that the expression of EGFP gene fused with porcineα1,3GT gene was partly inhibited.

Expression of GST-IL-1 fusion gene

Two GST-IL-1 fusion genes were constructed by inserting different cDNA fragments of human interleukin1 (IL-1) into the 3'-terminus of GST gene in the fusion protein expression vector pGEX-4T. After IPTG induction ,SDS-PAGE was employed to detect the gene expression. No corresponding protein encoded by GST gene fused with the whole-length 816 bp IL-1 cDNA was observed, nor was free GST protein. However, the fusion protein of GST and IL-1 cDNA without the 189 bp at the 5'- terminus was detected, amounting to 30% of the total bacterial protein expressed. This might suggest that the sequence of 1-189 bp of IL-1 cDNA affected the expression of the fusion gene. That is to say, the downstream sequence distant from the translation start codon AUG in the target gene could significantly affect the expression of the fusion gene.

Expression of a Carrot Antifreeze Protein Gene in Escherichia coli

The recombinant expression vector pET43.1b-AFP, which contains full encoding region of a carrot 36 kD antifreeze protein (AFP) gene was constructed. The recombinant was transformed into expression host carrying T7 RNA polymerase gene (DE3 lysogen) and induced by 1 mmol稬-1 IPTG (isopropyl--D-thiogalactoside) to express 110 kD polypeptide of AFP fusion protein. The analysis of product solubility revealed that pET43.1b-AFP was predominately soluble, and the expressed amount reached the maximum after the IPTG treatment for 3 h.

Construction of the recombinant expression vector for CD80-IgG fusion gene and its expression in Chinese hamster ovary cells

To construct the recombinant expression functionally in Chinese hamster ovary cells in order vector for CD80-IgG fusion gene and to express it to be used as an effective method to eliminate the immune escape of leukemic cells, the cDNA encoding the signal and extracellular domains of murine CD80 was generated by PCR amplification from plasmid pcDNMB7 containing the full length cDNA of murine CD80 and those of murine IgG1, in which the Fc fragment was obtained through RT-PCR amplification from murine spleen cells. These two cDNAs were then cloned in tandem into eukaryotic expression vector pcDNA3.0 and the resultant recombinant plasmid pcDNA/CD80-IgG was then transfected to Chinese hamster ovary cells with liposome transfection reagent. The cell clones constitutively expressing CD80-IgG fusion protein were obtained by G418 screening. Western blotting and dot ELISA assay were used to detect the expression of the fusion protein in the supernatants of these cells. Meanwhile, the fusion protein expressed was then purified with affinity chromatography, and its biological activity was demonstrated by flow cytometry, MTr colorimetry and ELISA assay. The experimental resuits showed that these two inserts were successfully cloned into plasmid pcDNA3.0, and the highly purified fusion protein was obtained. This fusion protein was proved to be able to upregulate the density of CD80 on leukemic cells, deliberately promote the proliferative reactions of mouse allogenic lymphocytes and increase the killing activity against WEHI-3 cells from 49.7 % up to 84.6 %. In addition, this fusion protein could also enhance the IL-2 secretion from allogenic lymphocytes activated by tumorspecific antigens. It is concluded that the recombinant vector constructed can be functionally expressed in the mammalian cells, thus providing a solid foundation for the further investigation on the mechanism to eliminate the immune escape of leukemic cells in vivo.

Application of GFP Gene in the Study of Insect-Resistant Transgenic Plants

用合成的cry1Ac基因与绿色荧光蛋白基因 (GFP)构成融合蛋白基因 ,然后和改造的GNA基因构建双价抗虫基因植物表达载体pBGbfg ,经根癌农杆菌介导转化了烟草。在紫外灯照射下 ,观察到转基因植株叶片中有较强的绿色荧光 ;经抗虫试验、PCR、Southernblot和Westernblot等检测 ,表明该重组植物表达载体能够在转基因植物中有效表达外源基因 ,转基因植株绿色荧光的表型与其抗虫性密切相关。从而成功地建立了以绿色荧光蛋白基因与抗虫基因组成的融合基因转化系统 ,简化了抗虫转基因植物筛选程序 ,有助于快速获得双价抗虫转基因植株。

蛋白激酶全抑制分析揭示KG-1细胞增殖的分子机制

目的:通过分析KG-1细胞对各种蛋白激酶抑制剂的反应,探讨其增殖的分子机制。方法:采用CCK-8法、实时荧光定量PCR(qRT-PCR)和Western-blot检测各种蛋白激酶抑制剂对KG-1细胞增殖、相关基因mRNA表达水平以及FGFR1下游信号通路蛋白磷酸化水平的影响。结果:NVP-BGJ398和PD173074有效抑制KG-1细胞的增殖,表明FGFR及其下游信号通路在KG-1细胞增殖过程中具有关键作用。使用FGFR抑制剂处理后,p-FGFR1和p-STAT5水平显著下降(P<0.001),p-Akt水平稍有下降(P<0.05),并未影响p-ERK水平(P>0.05)。结论:FGFR1OP2-FGFR1主要作用于下游STAT5信号通路,以促进细胞增殖。蛋白激酶全抑制分析是一种可靠而直接的方法,可用于确定癌细胞增殖的分子机制。

IN VITRO CO-STIMULATORY ACTIVITY OF HUMAN B7.2(IgV+C) PROTEIN PRODUCED BY ENGINEERED BACTERIA

Objective To express human B7. 2 extracellular domain with prokaryote expression system and to evaluate its biological activity in vitro. Methods PCR was used to amplify the extracellular region of human B7. 2 which contained both the IgV and IgC domains. The recombinant PGEX-4T-3/hB7. 2 (IgV+C) was obtained by cloning the PCR product into a prokaryote expression plasmid PGEX-4T-3 and was transformed into the host strain of DH5-a. Tke fusion protein consisted of GST and hB7. 2(IgV+C) was identified by SDS-PAGE and Western blotting. T cell activation was observed by exposing purified T lymphocytes to the fusion protein and [3H]-TdR incorporation with the presence of the first signal imitated hy anti-CD3 antibody. Results The fusion protein GST-hB7. 2 (IgV+ C) was produced and detected in inclusive body form from engineered bacterial cells. With the first signal existed,T lymphocytes proliferated when it was co-stimulated by the fusion protein. Conclusion These results indicated that the functional human B7. 2(IgV+C) fusion protein can be produced in bacterial cells and the fusion protein displays the co-stimulatory activity in T lymphocytes activation.

Construction of Prokaryotic Expression Vector of Mouse Nanog Gene and Its Expression

The aim of this study is to construct a prokaryotic expression vector of mouse Nanog gene and to express it in E. coli. A pair of primers was designed according to digestion sites in plasmid pGEX-KG and the Nanog gene sequence published by GenBank. The DNA fragment of 918 bp was amplified by polymerase chain reaction （PCR） from the pNA992 recombinant plasmid with Nanog gene, then cloned into pGEX-KG and transformed into the host E. coli strain TG Ⅰ. The sequence of the fragment was matched with the original sequence of pNA992. It indicated that fusion expression vector, pGEX-KG- Nanog, was constructed successfully. The pGEX-KG-Nanog plasmid was extracted from E. coli strain TG Ⅰ and was transformed into BL21（DE3） for expression. After induction by isopropyl-β-D-thiogalactoside （IPTG） at 37℃, the expression product of Nanog gene was identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis （SDS-PAGE）, and the expression condition was optimized. Nanog fusion protein was successfully expressed in the form of inclusion bodies. The molecular weight of the inclusion body was 63 kDa. Meanwhile, the optimum condition for the expression of Nanog fusion protein was induced with 0.8 mmol L^-1 IPTG for 5 h. The mouse Nanog gene was successfully expressed in E. coli, which laid a foundation for the purification of Nanog protein and for the preparation of polyclonal antibody.

Construction of the Eukaryotic Expression Vector with EGFP and hVE GF121 Gene and its Expression in Rat Mesenchymal Stem Cells

Objectives To construct a recombinant plasmid carrying enhanced green fluore- scent protein (EGFP) and human vascular endothelial growth factor (VEGF) 121 gene and detect its expre- ssion in rat mesenchymal stem cells (MSCs). Methods Human VEGF121 cDNA was amplified with polymerase chain reaction (PCR) from pCD/hVEGF121 and was inserted into the eukaryotic expression vector pEGFP- C1. After being identified with PCR, double enzyme digestion and DNA sequencing. The recombinant plasmid pEGFP/hVEGF121 was transferred into rat MSCs with lipofectamine. The expression of EGFP/VEGF121 fusion protein were detected with fluorescence microscope and immunocytochemical staining respectively. Results The recombinant plasmid was confirmed with PCR, double enzyme digestion and DNA sequencing. The fluoresce- nce microscope and immunocytochemical staining results showed that the EGFP and VEGF121 protein were expressed in MSCs 48 h after transfection. Conclusions The recombinant plasmid carrying EGFP and human VEGF was successfully constructed and expressed positively in rat MSCs. It offers a promise tool for further research on differentiation of MSCs and VEGF gene therapy for ischemial cardiovascular disease.

Roles of low?density lipoproteinreceptor?related protein 1 in tumors

Low-density lipoprotein receptor-related protein 1(LRP1,also known as CD91),a multifunctional endocytic and cell signaling receptor,is widely expressed on the surface of multiple cell types such as hepatocytes,fibroblasts,neurons,astrocytes,macrophages,smooth muscle cells,and malignant cells.Emerging in vitro and in vivo evidence demonstrates that LRP1 is critically involved in many processes that drive tumorigenesis and tumor progression.For example,LRP1 not only promotes tumor cell migration and invasion by regulating matrix metalloproteinase(MMP)-2and MMP-9 expression and functions but also inhibits cell apoptosis by regulating the insulin receptor,the serine/threonine protein kinase signaling pathway,and the expression of Caspase-3.LRPI-mediated phosphorylation of the extracellular signal-regulated kinase pathway and c-jun N-terminal kinase are also involved in tumor cell proliferation and invasion.In addition,LRP1 has been shown to be down-regulated by microRNA-205 and methylation of LRP1CpG islands.Furthermore,a novel fusion gene,LRP1-SNRNP25,promotes osteosarcoma cell invasion and migration.Only by understanding the mechanisms of these effects can we develop novel diagnostic and therapeutic strategies for cancers mediated by LRP1.

Construction and Expression of Prokaryotic Expression Vector of MPT-64 Gene

[Objective]Protective antigen gene MPT-64 was cloned from genomic DNA of Mycobacterium tuberculosis and transferred into prokaryotic competent cells for expression to obtain MPT-64 fusion protein.[Method]Based on the GenBank,primers were designed for amplification of MPT-64 gene,and the recombinant plasmid pET-32a-MPT-64 was constructed.The recombinant plasmid was expressed in prokaryotic expression vector to obtain fusion protein.[Result]Protective antigen gene MPT-64 was successfully cloned.The recombinant plasmid pET-32a-MPT-64 was obtained.MPT-64 fusion protein was successfully expressed.[Conclusion]This study laid solid foundation for the prevention,diagnosis,treatment of tuberculosis and the development of tuberculosis vaccines.

急性早幼粒细胞白血病完全缓解后分子生物学复发1例并文献复习

目的探讨复发性急性早幼粒细胞白血病(acute promyelocytic leukemia,APL)的分子生物学改变,为复发性APL的临床诊断和治疗提供指导。方法回顾性分析1例停药8个月后分子生物学复发的APL患儿的临床资料,并复习相关文献资料。结果患儿,男,1岁,以发热、皮肤出现出血点起病,查体示贫血貌,全身皮肤、黏膜散布出血点、瘀斑,左侧颈部可扪及数个肿大淋巴结,有融合,肝肋下2 cm,血常规示血红蛋白及血小板计数低,骨髓涂片示早幼粒细胞比例占75%,POX(+),骨髓PML/RARα融合基因聚合酶链式反应及荧光原位杂交检测均阳性,NRAS基因突变,初始符合APL的诊断标准。经规范治疗后,患儿骨髓涂片及微小残留完全缓解,PML/RARα融合基因转阴。停药8个月后复查患儿PML/RARαL型4.51%,考虑分子生物学复发,给予复发方案化疗,患儿PML/RARα转阴,继续规律化疗,同时行自体干细胞采集,定期复查。结论对于复发APL,一旦明确分子生物学复发后应尽快选择复发方案治疗,同时应注意定期检测PML/RARα融合基因,无法达到第二次分子生物学缓解时应考虑造血干细胞移植治疗。

敲低额外11-19白血病融合基因蛋白通过激活线粒体通路诱导非小细胞肺癌A549细胞凋亡

目的 探讨额外11-19白血病融合基因蛋白(extra eleven-nineteen leukemia fusion gene protein, EEN)对非小细胞肺癌(non-small cell lung cancer, NSCLC)的影响及其作用机制。方法 用免疫组织化学染色检测EEN在NSCLC组织和癌旁组织的表达水平,Western blot检测EEN在正常肺上皮细胞BEAS-2B细胞和NSCLC细胞A549细胞中的水平。在A549细胞中转染sh-EEN后,使用MTT测定细胞活性,Annexin V-FITC/PI流式细胞术和TUNEL染色分析细胞凋亡,使用荧光探针DCFH-DA测量细胞内ROS生成水平,使用JC-1染色测定线粒体膜电位的变化,通过Western blot分析凋亡相关蛋白水平。结果 与癌旁组织相比,EEN在NSCLC组织中表达上调;与BEAS-2B细胞相比,EEN在A549细胞中水平明显升高。沉默A549细胞EEN后,A549细胞生长受到抑制,细胞凋亡显著增加,ROS水平升高,线粒体膜电位丢失,Cyt C释放入细胞质,同时伴随着Bcl-2降低、Bax升高和Caspase-3活化。结论 EEN在NSCLC中表达增加。敲低EEN可诱导NSCLC细胞凋亡,且这一过程至少涉及到ROS/线粒体凋亡信号通路的激活。

我国部分地区不同动物来源新城疫病毒的分子流行病学研究

对从我国部分地区 1985～ 2 0 0 1年间分离的 2 6株新城疫病毒毒株进行研究 ,克隆其融合蛋白 (F)基因 ,分析相应的核苷酸 (nt)序列。根据绘制的系统进化发生树和F基因上三种限制性内切酶 (RE)位点分布 ,确定了这些毒株的基因型分类地位。除 2个毒株属于已知的VIb亚型外 ,其余 2 4个毒株分别属于新发现的基因Ⅸ型、Ⅵf亚型、Ⅵg亚型和VⅡc亚型。基因Ⅸ型毒株的F基因 5 4 0nt存在RsaⅠ位点 ,同时缺乏 1198ntHinfⅠ位点、14 78ntBstOⅠ位点和 16 2 5ntRsaⅠ位点 ;Ⅵf和Ⅵg亚型毒株不具有国外其它Ⅵ型毒株的 872ntRsaⅠ位点 ;Ⅶc亚型的RE位点分布和Ⅶa亚型、Ⅶb亚型、Ⅷ型毒株不同 ,鹅源毒株均出现 973ntRsaⅠ位点 ,7个鹅源毒株还出现了特有的 12 4 9ntRsaⅠ位点。在F基因编码的氨基酸中 ,基因Ⅸ型毒株出现Ile9→Val9和Val10 6→Ala10 6的替换 。

犬瘟热病毒野毒株融合蛋白主要功能区基因的变异研究

根据犬瘟热病毒（ＣＤＶ）融合蛋白（Ｆ）基因的核苷酸序列，设计合成了１０条引物。用１对引物从延吉犬病料中扩增出了含Ｆ２区基因的３１４ｂｐ的片段，除两端引物序列外为２６５ｂｐ，编码８８个氨基酸。它与日本弱毒株（ＣＤＶ－Ｊ）、Ｏｎｄｅｒｓｔｅｐｏｏｒｔ弱毒株（ＣＤＶ－ＯＮ）、海豹瘟热病毒２型（ＰＤＶ２）、１型（ＰＤＶ１）在核苷酸和氨基酸水平上的同源性，分别为９８．１％和９５．５％、９６．２％和９３．２％、９４．３％和９３．２％、７７．４％和８７．５％。对５份来自不同地区的ＣＤＶ病料的融合区基因片段进行了扩增、克隆和序列分析，其中北京１号犬（ＣＤＶ－Ｂ１）、２号犬（ＣＤＶ－Ｂ２）、沈阳犬（ＣＤＶ－Ｓ）和长春犬（ＣＤＶ－Ｚ）的２８３ｂｐ片段完全相同，而与哈尔滨犬（ＣＤＶ－Ｈ）的该片段有３个核苷酸和２个氨基酸不同。在核苷酸和氨基酸水平，北京犬野毒株等与ＣＤＶ－Ｈ、ＣＤＶ－Ｊ、ＣＤＶ－ＯＮ、ＰＤＶ２、ＰＤＶ１的同源性分别为９８．９％和９７．９％、９７．９％和９５．８％、９６．５％和９７．９％、９３．３％和９８．９％、７７．０％和８４．２％。本研究揭示了ＣＤＶ的流行毒株和相关毒株在融合蛋白上的亲缘关系，进一步证实了ＰＤＶ２?

新城疫病毒F_(48)E_8株融合蛋白基因序列分析

本研究报道了新城疫病毒（ＮＤＶ）中国标准强毒株Ｆ４８Ｅ８融合蛋白（Ｆ）基因的序列。该基因核苷酸序列长度为１７００ｂｐ，编码由５５３个氨基酸组成的Ｆ０多肽。Ｆ０酶切激活部位序列为ＲＲＱＲＲ↓Ｆ，具有ＮＤＶ强毒的特征。Ｆ０中有３个主要由疏水性氨基酸组成的区域和６个可糖基化位点。经比较，ＮＤＶＦ４８Ｅ８株和Ｍｉｙａｄｅｒａ株、ＴｅｘａｓＧＢ株的氨基酸同源性分别为９３６４％和９２４１％。

犬瘟热病毒小熊猫株核蛋白和融合蛋白基因克隆及序列分析

根据GenBank中报道的CDV核苷酸序列,设计合成了2对特异性引物,对犬瘟热病毒小熊猫株(CDVLP)核蛋白(N)和融合蛋白(F)两种主要结构蛋白基因进行了克隆、测序及序列分析。结果表明,CDVLP株N蛋白基因全长1571bp,预测编码523个氨基酸;F蛋白基因全长1989bp,预测编码662个氨基酸,F蛋白氨基酸序列中含有5个潜在的N-联糖基化位点。聚类分析提示,CDVLP株是一株与CDV强毒株亲源关系很近的毒株。用DNAstar软件对CDVLP株和Onderstepoort弱毒株N蛋白和F蛋白进行了疏水性及抗原表位预测分析。抗原表位差异提示CDVLP毒株N和F蛋白的免疫原性可能要优于Onderstepoort弱毒株。在分子水平上阐明了CDVLP株的N和F蛋白基因更适合作为构建基因疫苗和重组活载体疫苗的目的基因。