Cloning of a flower-specific expression promoter from Arabidopsis thaliana and its plant expression vector construction

Given the sequence of Chs gene promoter from Arabidopsis thaliana reported in GenBank （AF248988）, a pair of specific PCR primers was designed with the Primer Premier 5.0 software. PCR products of about 0.5 kb were successfully amplified with the genome DNA of A. thaliana as a DNA template and Taq polymerase as DNA polymerase. The purified PCR products were ligated to the pMD18-T vector. The sequencing result showed that the Chs promoter from A. thaliana was 531 bp long. Sequence alignment analysis based on the DNAMAN software revealed that the sequence similarity between the cloned promoter and target promoter （AF248988） was up to 100%. Online PLACE analysis indicated that the Chs promoter contained cis-elements such as TATA-box, CAAT-box, pollen-box, G-box, ACGT-containing element, R response element, Myb recognition element and TACPyAT-box. At the same time, a plant expression vectorpAtChs：：GUS which fused the Chs promoter and the marker gene GUS was successfully constructed.

Cloning of XET gene from Anthocephalus chinensis and its plant expression vector construction

A full-length cDNA sequence of xyloglucan endotransglycosylase gene （XET）, abundantly expressed in the cambium of Anthocephalus chinensis was cloned by conserved PCR, rapid-amplification of cDNA ends and by chromosome walking. Analytical results of the DNA sequence show that a 912 bp complete open reading frame （ORF） encoded a 303-amino acid protein was in the 1205 bp full cDNA sequence. The deduced amino acid sequence of AcXET, which contained the conserved specific EIDFE catalytic site sequence to XETs was homologous to the other known XET proteins. In order to study the gene function of AcXET and obtain transgenic plants, a plant expression vector pBIAcXET was constructed by recombinating the AcXET fragment from the cloning vector pMD19AcXET and the binary vector pBI121 between the XbaI and SmaI sites. The fragment ofAcXET gene was inserted between the CaMV 35S promotor and the coding region of the GUS gene in pBI121. The identification results show that the plant expression binary vector pBIAcXET was constructed successfully. These results lay the foundation for studying the molecular mechanism ofAcXET gene during wood formation.

Gene Cloning of Murine α-Fetoprotein Gene and Construction of Its Eukaryotic Expression Vector and Expression in CHO Cells

To clone the murine α fetoprotein (AFP) gene, construct the eukaryotic expression vector of AFP and express in CHO cells, total RNA were extracted from Hepa 1 6 cells, and then the murine α fetoprotein gene was amplified by RT PCR and cloned into the eukaryotic expression vector pcDNA3.1. The recombinant of vector was identified by restriction enzyme analysis and sequencing. After transient transfection of CHO cells with the vector, Western blotting was used to detect the expression of AFP. It is concluded that the 1.8kb murine α fetoprotein gene was successfully cloned and its eukaryotic expression vector was successfully constructed.

Expression Vector Construction and Genetic Transformation of <i>Rosa rugosa β</i>-l,3-Glucanase Gene (<i>RrGlu</i>)

In order to lay a foundation for researching the function of Rosa rugose (R. rugosa) RrGlu gene, the RrGlu gene was amplified from the styles of R. rugosa “Tanghong”, a gene expression vector named PBI121-RrGlu was constructed and the vector was introduced into tobacco with the agrobacterium-mediated method. PCR results showed that the RrGlu gene was integrated into the tobacco genome.

Construction of Expression Vector for Porcine Gastrin-releasing Peptide Fusion Protein

[Objectives]This study was conducted to obtain porcine gastrin-releasing peptide(GRP)fusion protein.[Methods]The constructed pET32a(+)-GRP plasmid was transformed into Escherichia coli BL21(DE3)competent cells to obtain the pET32a(+)-GRP-BL21(DE3)fusion protein expression strain,which was induced with 0.5 mM IPTG at 25℃and 150 r/min for 12 h,and the His-tagged GRP fusion protein was detected by SDS-Page gel electrophoresis and Western Blot.[Results]After optimizing the IPTG-induced expression conditions,it was confirmed that the porcine GRP fusion protein was obtained,and the porcine GRP fusion protein was soluble,stable and highly active.[Conclusions]This study lays a foundation for the subsequent preparation of anti-pig GRP antibodies.

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 recombinant plasmid and prokaryotic expression in E. Coli and biological activity analysis of human placenta arresten gene

BACKGROUND: The proliferation and metastasis of cancers depend on angiogenesis. This property provides the feasibility for the treatment of cancer by inhibition of angiogenesis, and many angiogenic inhibitors have been demonstrated to effectively inhibit angiogenesis and consequently the growth of solid cancer. As for the newly identified angiogenesis inhibitor, arresten, some studies have found its high activity on restrainting tumor vessel. This study was to assess the anti-angiogenic activity of arresten. METHODS: The arresten gene was obtained from a healthy puerpera's placenta tissue by the reverse transcriptase-polymerase chain reaction (RT-PCR) method, and molecular cloning to prokaryotic expression plasmid pBV220 by recombination strategy. The prokaryotic expression plasmid pBV220/arr was identified by restriction enzyme digestion and sequenced. The pBV220/arr was transformed into E. coli JM109, DH5α, BL21 and BL21 (DE3) by the CaCl_2 transformation method. The arresten expression level was detected by SDS-PAGE. The expressed product was purlfled, re-naturalized and detected for its biological activity of inhibiting the angiogenesis of chorioallantoic membrane (CAM). RESULTS: The arresten gene was cloned and pBV220/arr was constructed. The arresten expression level of protein was highly increased after pBV220/arr was transformed into E. coli BL21 (DE3). SDS-PAGE showed that the expressed arresten proteins were mainly inclusion bodies and had a molecular weight of 26 kDa. The expressed arresten protein showed evident biological activities. CONCLUSIONS: The successful construction of recombinant plasmid pBV220/arr and the effective expression in E. coil have laid a foundation for further study of its anti-angiogenic function and may pave the way for future antitumor application.

A versatile cloning vector facilitates target geneexpression in prokaryotic and eukaryotic cells

Objective: To facilitate manipulation of gene expression in different host cells, we used pEGFP-N1 as backbone to construct a versatile vector that can drive foreign gene expression in prokaryotic and eukaryotic cells. Methods: A cloning and expression vector, pEGFP-N1-lac, was constructed by inserting the prokaryotic lac promoter of pUC19 into the eukaryotic expression vector, pEGFP-N1, between the eukaryotic PCMV promoter and enhanced green fluorescent protein (EGFP) open reading frames. To assess the function of pEGFP-N1-lac, the nucleotide sequence encoding the hepatitis C virus (HCV) core protein was cloned into the multiple cloning sites. Western blotting analysis was used to detect the expression of the HCV core protein in Escherichia coli DH5α and HepG2 cells. Results: Restriction enzymedigestion and sequence analysis indicated that pEGFP-N1-lac was successfully constructed and the HCV core gene was cloned into this vector. The Western blotting results showed that pEGFP-N1-lac promoted expression of HCV core gene in prokaryotic E. coli DH5α and eukaryotic HepG2 cells. Conclusion: The pEGFP-N1-lac vector has been successfully constructed and functions in both prokaryotic and eukaryotic cells. The EGFP reporter can be used as an insert-inactivation marker for clone selection or as an expression tag. This vector can be used for cloning and expression of genes in both prokaryotic and eukaryotic cells, making gene cloning, expression and functional studies convenient as well as time- and labor-efficient.

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.

A Plasmid vector encoding functional human keratinocyte growth factor gene in vitro—Functional human KGF gene expression in vitro

In this study, we cloned human KGF (hKGF) genes using RT-PCR techniques and developed a eukaryotic expression plasmid vector capable of directing the expression of functional hKGF. Monolayer culture of human embryo lung fibro-blast (HLF) was used for isolation of total RNA. Then the total RNA was purified and reverse- transcribed into cDNA using an oligo (dT) primer. A full PCR fragment for hKGF was generated and cloned. Restriction digestion and nucleo-tide sequence analysis validated the complete hKGF transcription. The hKGF cDNA fragment was inserted into pEGFP-C2 vector by means of recombinant DNA technology and verified by restriction analysis and sequencing. We have constructed pEGFP-C2-hKGF encoding the green fluorescent protein (GFP). Furthermore, hKGF had the effect on AEC II proliferation. These results suggest that the potential appli-cation of a hKGF plasmid of gene expression should be useful for sustained AEC proliferation, and its in vivo efficacy needs to be validated. Keywords:

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-Fc (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 prokaryotic expression system. The infusion protein could promote neurite outgrowth of DRG neurons cultured with MAG.

Cloning, construction of prokaryotic expression vector and expression of Escherichia coli cytosine deaminase gene

Cytosine deaminase gene of Escherichia coli strain H30 was cloned, and its initiation codon of ’GTG’ was mutated to ’ATG’ by PCR. Prokaryotic recombinant expression vector pBV220CD was constructed. Clone with high enzyme activity were selected by detecting their specific activity of cytosine deaminase. 5FC（5FC, 5fluorocytosine） could induce the lethal toxicity to cells containing active CD gene. DNA sequence analysis indicated that there were 16 altered bases and 5 of them resulted in the alteration of amino acids in predicted peptide by comparing DNA sequence of the clone H30CD11 with high enzyme activity with CD gene reported in Gene Bank.

植酸酶基因在嗜酸乳杆菌中的表达

植酸酶和嗜酸乳杆菌是重要的饲料添加剂,为获得产植酸酶的嗜酸乳杆菌菌株,克隆了大肠杆菌植酸酶基因,构建表达载体并转化嗜酸乳杆菌,对重组嗜酸乳杆菌进行发酵产酶并测定所产酶液的酶学性质,进一步研究重组嗜酸乳杆菌的耐酸性及植酸酶液的抗蛋白酶活性。结果表明:重组嗜酸乳杆菌发酵24 h植酸酶活性为984 U/mL,植酸酶的最适催化pH为4.5,最适催化温度为60℃。重组嗜酸乳杆菌在pH 2.0~4.5有一定的耐酸性,在pH 2.0条件下2 h的存活率为76.4%。植酸酶液用胃蛋白酶处理160 min后植酸酶液剩余85%的相对酶活,用胰蛋白酶处理160 min后剩余29%的相对酶活。上述研究结果为重组嗜酸乳杆菌后续应用研究提供了重要依据。

绵羊GSTA2基因克隆、生物信息学分析及真核表达载体构建

为阐明绵羊谷胱甘肽S转移酶α2(Glutathione S-transferase alpha 2,GSTA2)基因功能,利用牛GSTA2基因序列设计引物,提取绵羊皮肤组织总RNA,应用RT-PCR、基因克隆、生物信息学对GSTA2基因进行研究,构建真核表达载体,转染绵羊皮肤成纤维细胞,应用qPCR技术检测GSTA2基因的表达。结果表明,克隆到绵羊GSTA2基因672 bp编码区序列(GenBank登录号:OR440604.1),编码223个氨基酸,分子量为25.39 ku。氨基酸比对和系统进化树分析表明,绵羊与牛的GSTA2相似度最高,达87.39%。GSTA2的二级结构以α-螺旋和无规则卷曲为主。构建的真核表达载体pcDNA3.1-GSTA2转染绵羊皮肤成纤维细胞后,GSTA2基因表达量极显著上调(P <0.001)。说明成功克隆了绵羊新基因GSTA2的CDS序列,并成功构建了其真核表达载体。

苦瓜McPDS基因克隆及CRISPR/Cas9基因编辑载体构建

以苦瓜八氢番茄红素脱氢酶(phytoene dehydrogenase,PDS)基因为靶标,构建其特异gRNA的CRISPR/Cas9基因编辑载体,以期为建立苦瓜CRISPR/Cas9基因编辑技术体系奠定基础。以苦瓜自交系B07叶片cDNA为模板,同源克隆苦瓜McPDS基因CDS序列。结果表明,McPDS基因CDS序列全长1731 bp,编码576个氨基酸,蛋白质相对分子质量为64.44 kD,理论等电点(PI)为7.09。跨膜结构分析结果表明,该蛋白为亲水性非跨膜蛋白。系统进化树分析结果表明,McPDS与黄瓜、甜瓜等葫芦科植物中的PDS蛋白同源性较高。此外,以McPDS为靶标基因,在5’端筛选2个高特异性靶点,经设计引物,成功构建1个双靶点CRISPR/Cas9基因编辑载体,为苦瓜基因编辑体系的建立奠定了技术基础。