Preparation,identification and comparison of murine and rabbit polyclonal antibodies against matrix protein of rabies virus strain CVS-11 / 中国生物制品学杂志

@#Objective To prepare murine and rabbit polyclonal antibodies against rabies virus(RV) matrix(M) protein and compare their reactivity.Methods The prokaryotic expression vector pET-28a-M was constructed by using the cDNA of cells infected with RV CVS-11 strain as template,then transformed into E.coli BL21(DE3),and the induced by IPTG to express M protein.After nickel column affinity chromatography and dialysis renaturation,female BALB/c mice and New Zealand white rabbits were immunized with the M protein,and the whole blood was taken to separate the serum.The titers of the murine and rabbit polyclonal antibodies were detected by ELISA,and the reactivity was measured by Western blot,indirect immunofluorescence assay(IFA) and immunoprecipitation(IP).Results The plasmid pET-28a-M was constructed correctly as identified by sequencing.The titers of murine and rabbit polyclonal antibodies were 1:100 and 1:256 000respectively,and the polyclonal antibodies had reactivity with different RV strains.Conclusion The murine and rabbit polyclonal antibodies against M protein were successfully prepared,which provides important biological tools for exploring the interaction between M protein and host protein as well as studying the pathogenesis of RV.

Construction of a replicative expression vector based on the porcine circovirus 2 replicon / 生物工程学报

The antigen gene expression level of a DNA vaccine is the key factor influencing the efficacy of the DNA vaccine. Accordingly, one of the ways to improve the antigen gene expression level of a DNA vaccine is to utilize a plasmid vector that is replicable in eukaryotic cells. A replicative DNA vaccine vector pCMVori was constructed based on the non-replicative pcDNA3.1 and the replicon of porcine circovirus 2 (PCV2) in this study. An EGFP gene was cloned into pCMVori and the control plasmid pcDNA3.1. The two recombinant vectors were transfected into PK-15 cell, and the plasmid DNA and RNA were extracted from the transfected cells. Real-time PCR was used to determine the plasmid replication efficiency of the two plasmids using plasmid before and after Bcl Ⅰ digestion as templates, and the transcription level of the Rep gene in PCV2 replicon was detected by RT-PCR. The average fluorescence intensity of cells transfected with the two plasmids was analyzed with software Image J, and the transcription level of EGFP was determined by means of real-time RT-PCR. The results showed that the replication efficiency of pCMVori in PK-15 cells incubated for 48 h was 136%, and the transcriptions of Rep and Rep' were verified by RT-PCR. The average fluorescence intensity of the cells transfected with pCMVori-EGFP was 39.14% higher than that of pcDNA3.1-EGFP, and the transcription level of EGFP in the former was also 40% higher than that in the latter. In conclusion, the DNA vaccine vector pCMVori constructed in this study can independently replicate in eukaryotic cells. As a result, the expression level of cloned target gene was elevated, providing a basis for developing the pCMVori-based DNA vaccine.

Analysis of endogenous plasmids in Lacticaseibacillus paracasei ZY-1 and development of expression vectors / 生物工程学报

The construction of efficient and stable Lactobacillus expression vector is critical for strain improvement and development of customized strains. In this study, four endogenous plasmids were isolated from Lacticaseibacillus paracasei ZY-1 and subjected to functional analysis. The Escherichia coli-Lactobacillus shuttle vectors pLPZ3N and pLPZ4N were constructed by combining the replicon rep from pLPZ3 or pLPZ4, the chloramphenicol acetyltransferase gene cat from pNZ5319 and the replicon ori from pUC19. Moreover, the expression vectors pLPZ3E and pLPZ4E with the promoter Pldh3 of lactic acid dehydrogenase and the mCherry red fluorescent protein as a reporter gene were obtained. The size of pLPZ3 and pLPZ4 were 6 289 bp and 5 087 bp, respectively, and its GC content, 40.94% and 39.51%, were similar. Both shuttle vectors were successfully transformed into Lacticaseibacillus, and the transformation efficiency of pLPZ4N (5.23×102-8.93×102 CFU/μg) was slightly higher than that of pLPZ3N. Furthermore, the mCherry fluorescent protein was successfully expressed after transforming the expression plasmids pLPZ3E and pLPZ4E into L. paracasei S-NB. The β-galactosidase activity of the recombinant strain obtained from the plasmid pLPZ4E-lacG constructed with Pldh3 as promoter was higher than that of the wild-type strain. The construction of shuttle vectors and expression vectors provide novel molecular tools for the genetic engineering of Lacticaseibacillus strains.

DNA Damage-Inducible Transcript 4 (Ddit4) Overexpression Could Inhibit Proliferation and Promote Apoptosis of HT-22 Cells through the Wnt / β-catenin Signaling Pathway / 中国生物化学与分子生物学报

Neural tube defects (NTDs) are congenital defect diseases caused by cell proliferation and apoptosis disorders. Using RNA-Seq assays, we found the increased expression of DNA damage-inducible transcript 4 (Ddit4) in embryonic brain tissues from NTD fetuses. In this study, we intend to explore the effects of Ddit4 overexpression on the proliferation and apoptosis of HT-22 cells and related mechanisms to lay the foundation for the study of the role of Ddit4 in NTDs. According to the mouse Ddit4 sequence, we constructed the eukaryotic expression vector pEX-3-Ddit4. The results of restriction enzyme analysis and sequencing showed that the eukaryotic expression vector pEX-3-Ddit4 was successfully constructed. qRT-PCR and Western blotting results showed that the expression level of Ddit4 in HT-22 cells was significantly increased after transfection of PEX-3-Ddit4 (P < 0. 01) . CCK-8 and Western blotting results showed that Ddit4 overexpression decreased the proliferation of HT-22 cells (P < 0. 01) . Flow cytometry showed that Ddit4 overexpression increased the proportion of cells in the G

Construction of a broad host range expression plasmid vector by Golden Gate cloning

Aims@#Expression of recombinant proteins across a range of different host organisms has profound contribution to the advancement in biotechnology. In this study, we aimed to construct a highly versatile broad host range (BHR) expression vector, designated as pYL101C.@*Methodology and results@#The Golden Gate cloning approach was used to construct pYL101C. Key features of pYL101C include a strong integron promoter (PINTc), a BHR pBBR1 origin of replication (ori), gentamycin resistance gene (GmR) as a selectable marker and a multiple cloning site (MCS) downstream of the promoter for easy-cloning purpose. To verify the functionality of pYL101C, we cloned the superfolder green fluorescent protein (sfGFP) reporter gene into pYL101C and transferred the resultant recombinant plasmid pYL101C::sfGFP into various Gram-negative bacteria. Transformants obtained stably expressed strong green fluorescence under blue light excitation even without selection after four passages. @*Conclusion, significance and impact of study@#The constructed BHR expression vector, pYL101C and recombinant pYL101C::sfGFP are stable and can be used to monitor the presence of Gram-negative bacteria, such as endophytes and pathogens in their hosts and environment.

Prokaryotic expression, purification and characterization of tissue inhibitor of metalloproteinase-2 / 生物工程学报

Tissue inhibitor of metalloproteinases-2 (TIMP-2) inhibits tumor migration and invasion. Obtaining TIMP-2 protein is conducive to a comprehensive and in-depth study of its function and mechanism in tumorigenesis and development. We collected human TIMP-2 protein through prokaryotic expression in vitro. We expressed, purified and characterized human TIMP-2 protein. First, the human TIMP-2 gene was cloned from the cDNA obtained by reverse transcription of total RNA of human lung cancer A549 cells, and constructed to pET28a vector. The recombinant plasmid pET28a-TIMP-2 was transformed into Escherichia coli BL21(DE3) after restriction endonuclease digestion and sequencing analysis. The expression of TIMP-2 protein was induced by isopropyl-β-D-thiogalactoside (IPTG), and the expression conditions were optimized. After purification by nickel affinity column, the fusion protein His-TIMP-2 was identified by Western blotting method and its biological activity was detected by gelatin zymography. The fusion protein His-TIMP-2 existed in the form of inclusion body in E. coli. In a certain range, the concentration of IPTG had no significant effect on the expression amount of His-TIMP-2. But in this expression system, induction temperature and time were the key parameters, and the expression amount of His-TIMP-2 in E. coli increased with the increase of induction temperature. The purified and refolded fusion protein could effectively inhibit the activity of matrix metalloproteinases expressed by human lung cancer A549 cells. The acquisition of active fusion protein lays a foundation for further study of the function and mechanism of human TIMP-2, and is of great significance for tumor therapy.

Cloning of AhWRKY33 from Asarum heterotropoides and its genetic transformation in Arabidopsis / 中国中药杂志

The WRKY family genes, which play an important role in plant morphogenesis and stress response, were selected based on the data of the full-length transcriptome of Asarum heterotropoides. Using AtWRKY33, which regulates the synthesis of the camalexin in the model plant Arabidopsis to compare homologous genes in A. heterotropoides, primers were designed to amplify the open reading frame(ORF) fragment of AhWRKY33 gene by RT-PCR using total RNA of A. heterotropoides leaves as template. Real-time PCR results showed that there was a significant difference between the aerial part and the underground part of A. heterotropoides, the toxic aristolochic acid content is highly expressed in the leaves higher than the root. After verification, the WRKY33 gene of A. heterotropoides is ORF long 1 686 bp, encoding 561 amino acids.AhWRKY33 had two conserved WRKYGQK domains. According to the classical classification, it belongs to group Ⅰ WRKY transcription factor. A. heterotropoides WRKY33 had some homology with amino acids of other species. The study successfully constructed the plant eukaryotic expression vector PHG-AhWRKY33 and transformed Arabidopsis thaliana, the transgenic Arabidopsis was obtained by PCR detection and hygromycin resistant plate screening. It found that the germination of transgenic Arabidopsis seeds was accelerated and the stress resistance was increased. It laid a foundation for further analysis of WRKY transcription factor in the growth and development of A. heterotropoides and the synthesis of secondary metabolites.

Expression Enhancement Of Trastuzumab In Cho Cells Using Codon Optimization And Promoter Selection For Mammalian Expression Vector

Trastuzumab is recombinant humanized monoclonal IgG antibody used in the treatment of metastatic breast cancer. It blocks the overexpression of tyrosine kinase Her 2 family receptors and downregulation of pathways. Genetic optimizations like gene optimization and expression vector optimization are the key elements to enhance monoclonal antibody expression. Expression vector optimization includes major parameters like selection of right promoters, poly A tail selection of genome integrating elements. Codon optimization is gene designing approach without affecting the amino acid sequence of the protein. Current research work involves development of codon optimization algorithm for trastuzumab heavy and light chain gene and comparative analysis of expression in different vectors.

Cloning and expression analysis of CtbHLH transcription factor gene from Carthamus tinctorius and construction of plant expression vector / 中国中药杂志

To clone bHLH( basic helix-loop-helix) gene from Carthamus tinctorius,analyze the expression level in different plant tissues and construct the plant expression vector. The bHLH1 gene was cloned by RT-PCR techniques,and the protein characteristics were analyzed by bioinformatics,and phylogenetic tree was constructed. The expression of bHLH1 gene in different tissues and the roots after inoculated by Fusarium oxysporum were analyzed using real time-PCR,and the plant expression vector p BASTA-bHLH1 was constructed. The obtained ORF sequence of bHLH1 gene was 897 bp,encoded a protein of 298 amino acids. Sequence alignment and phylogenetic tree analyses showed that C. tinctorius bHLH1 had a certain homology with other species of amino acids,and was the most similar to the amino acid sequence of tobacco. Real-time PCR results showed significant differences,CtbHLH1 gene in red flower petals in different tissues and different flowering period had remarkable difference in expression level,its high amount expressed in petals,flowers third day after blossom expressed the highest quantity,at the end of the flowering the expression quantity is low. In addition,it is expressed in the root,and the expression in the stem and leaves is extremely low. The bHLH1 gene of C. tinctorius is successfully cloned,and the expression is analyzed. The plant expression vector p BASTA-bHLH is constructed.

Cloning of ERF1 transcription factor from Carthamus tinctorius and construction of plant expression vector / 中草药

Objective: To clone a coding region sequence of AP2/ERF transcription factor family from Carthamus tinctorius, and construct a plant expression vector. Methods: A gene (CtERF1) of AP2/ERF family transcription factor was cloned by RT-PCR based on the sequence of C. tinctorius transcription sequencing, the phylogenetic tree was constructed by ClustalW 1.83 software, Spe I and Xba I restriction sites were introduced to construct over-expression vector pBASTA-CtERF1 containing 35S promoter. Results: CtERF1 gene had a functional domain of a typical AP2/ERF gene encoding 297 amino acids, and contained an AP2 region speculated to be located in cytoplasm and nucleus, which was ERF subprotein. Systematic evolution analysis showed that CtERF1 gene had some homology with other plant species, among which the relationship with Populus deltoides and Panax japonicus were the closest. The pBASTA-CtERF1 plant expression vector was constructed successfully by molecular biology. Conclusion: A CtERF1 gene of C. tinctorius AP2/ERF transcription factor family was cloned and the plant expression vector pBASTA-CtERF1 was constructed successfully.

Construction and identification of recombinant lentiviral plasmid of receptor for advanced glycation end products / 国际生物医学工程杂志

Objective To construct a recombinant lentiviral plasmid of receptor for advanced glycation end products (RAGE) and establish RAGE stable expressing hepatocellular carcinoma cell models in order to explore the pathogenesis of RAGE in the occurrence and development of hepatocellular carcinoma. Methods RAGE gene fragments were amplified by PCR and cloned into the lentiviral expression vector pCDH-CMV-MCS-EF1-Puro. Then the recombinant lentiviral plasmid and packaging plasmid were used to package lentivirus in HEK293T cells by calcium phosphate transfection. Lentivirus supernatant was collected to infect hepatoma cells HepG2 and Huh7. After that cells were screened by puromycin. Finally, RAGE expression was detected by real-time PCR and Western blot. Results RAGE gene fragment was successfully amplified and inserted into lentiviral expression vector. After packaging the lentivirus-infected liver cancer cells, real-time quantitative PCR and Western blot results showed that the mRNA (P<0.05) and protein expression of RAGE cells stably expressing RAGE were significantly higher than that of the control cells. Conclusions The RAGE overexpressing hepatocarcinoma cell line was successfully constructed by using lentiviral expression vector, which laid a good foundation for further study on the pathogenesis of RAGE.

Cloning and heterologous expression of a hydrophobin gene Ltr. hyd from the tiger milk mushroom Lentinus tuber-regium in yeast-like cells of Tremella fuciformis

Background: Hydrophobins are small proteins secreted by filamentous fungi, which show a highly surface activity. Because of the signally self-assembling abilities and surface activities, hydrophobins were considered as candidates in many aspects, for example, stabilizing foams and emulsions in food products. Lentinus tuber-regium, known as tiger milk mushroom, is both an edible and medicinal sclerotium-producing mushroom. Up to now, the hydrophobins of L. tuber-regium have not been identified. Results: In this paper, a Class I hydrophobin gene, Ltr.hyd, was cloned from L. tuber-regium and expressed in the yeast-like cells of Tremella fuciformis mediated by Agrobacterium tumefaciens. The expression vector pGEH-GH was under the control of T. fuciformis glyceraldehyde-3-phosphate dehydrogenase gene (gpd) promoter. The integration of Ltr.hyd into the genome of T. fuciformis was confirmed by PCR, Southern blot, fluorescence observation and quantitative real-time PCR (qRT-PCR). Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that recombinant hydrophobin rLtr.HYD with an expected molecular mass of 13 kDa was extracted. The yield of rLtr.HYD was 0.66 mg/g dry weight. The emulsifying activity of rLtr.HYD was better than the typical food emulsifiers sodium caseinate and Tween 20. Conclusions: We evaluated the emulsifying property of hydrophobin Ltr.HYD, which can be potentially used as a food emulsifier.

Cloning, bioinformatics, and expression analysis of MpF2H gene in Microcos paniculata / 中草药

Objective To obtain the key enzyme gene involved in flavone C-glycosides biosynthesis pathway, a flavanone 2-hydroxylase (F2H) gene was cloned from Microcos paniculata, and its bioinformatics analysis and gene expression pattern were also performed. Methods The specific primers were designed according to Unigene in F2H annotated in the transcriptome data of M. paniculata. The open reading frame (ORF) of MpF2H gene was amplified by PCR. Then the PCR product was purified and ligated to pET30a, and finally a prokaryotic expression vector pET30a-MpF2H was constructed. The bioinformation of F2H gene cDNA sequences was analyzed by some online tools. Using RT-qPCR with suitable primers, the quantitative expression analysis of MpF2H gene in different tissues, namely, buds, leaves, twigs, flowers and fruits was carried out. Results The length of MpF2H gene ORF was 1 557 bp (GenBank accession number KY652921), which encoded a protein with 518 amino acid residues, relative molecular weight of 54 500, theory isoelectric point of 5.49. In which was no transmembrane domain. It was hypothesized that this protein located in chloroplast. MpF2H gene was expressed in different tissues, with the highest expression in leaves and the lowest expression in twigs and flowers. Conclusion The expression of MpF2H gene varied widely in different tissues. The MpF2H gene was cloned from M. paniculata based on pET30a-MpF2H expression vector. This study will provide the fundamental information for the further preparation and functional research of MpF2H protein in flavone C-glycosides biosynthesis pathway.

Cloning and expression pattern analysis of chalcone synthase gene in Microcos paniculata / 中草药

Objective To clone the full-length cDNA of MpCHS and analyze its expression pattern in different parts of Microcos paniculata and different growth periods of M. paniculata leaves. Methods Based on the transcriptome data of M. paniculata, we designed specific primers for MpCHS gene. The full-length cDNA of MpCHS was amplified by PCR and the positive clones were then sequenced, analyzed, and constructed prokaryotic expression vector. The bioinformatics analysis of MpCHS was also performed. Meanwhile, the mRNA expression of MpCHS was detected using real-time quantitative PCR. Results The relative molecular mass was 42 700, and its theoretical isoelectric point was 6.11, with three conserved functional active sites (165 C, 304 H, and 337 N) of the CHS family proteins and the tag sequence of RLMMYQQGCFAGGTVLR and GVLFGFGPGL. Phylogenetic tree analysis showed that MpCHS had close relationship with woody plants such as cocoa and upland cotton. We successfully cloned the full-length cDNA of MpCHS (GenBank: KY472608). It had an ORF of 1 176 bp which encoded a protein of 391 amino acid residues. RT-qPCR results showed that MpCHS was expressed in all parts of M. paniculata and its expression in leaves was gradually decreased along with its development. Conclusion MpCHS is cloned from M. paniculate for the first time, and the gene expression pattern of MpCHS in different parts of M. paniculata and different growth periods of M. paniculata leaves was analyzed. This study facilitates the further purification and functional validation of MpCHS protein and provides reference for further analysis of flavonoids biosynthesis pathway in M. paniculata.

Establishment of pancreatic mucinous cystadenocarcinoma cell line MCC1 with stable overexpression of miR-224 / 中国肿瘤生物治疗杂志

@#Objective: To construct a hsa-microRNA-224(miR-224) lentiviral expression vector and to establish pancreatic mucinous cystadenocarcinoma MCC1 cell line with stable miR-224 over-expression. Methods: Pri-miR-224 gene fragment was designed and amplified by quantitative real-time polymerase chain reaction (qRT-PCR), and then loaded into GV369 lentiviral vectors (GV369-miR224) by gene recombination technology. GV369-miR-224 lentivrial expression vectors were then identified by PCR and DNA sequencing. The GV369-miR-224 vector fluid was then used to infect pancreatic mucinous cystadenocarcinoma MCC1 cell line to establish the MCC1 cell line stably over-expressing miR-224. The transfection efficiency of GV369-NC and GV369-miR-224 was observed under fluorescence microscopy; and the expression levels of miR-224 in MCC1, GV369-miR-224-MCC1 and GV369-NC-MCC1 cell lines were detected by RT-PCR. Results: The GV369-miR-224 lentiviral vectors were successfully constructed. GV369-miR-224-MCC1 and GV369-NC-MCC1 cells all emit green fluorescence under the fluorescence microscope. The expression level of miR-224 in GV369miR-224-MCC1 cell group was significantly higher than that in negative control GV369-miR-224-MCC1 group and blank control MCC1 cell group (23.45±1.94， 1.46±0.1 and 2.11±0.38, P<0.01), however, there was no significant difference between the two control groups (P>0.05). Conclusion: A pancreatic mucinous cystadenocarcinoma MCC1 cell line with stable miR-224 over-expression was successfully established, and this will provide a new cell model for exploring the function and pathogenesis of miR-224 in pancreatic mucinous cystadenocarcinoma.

Construction and characterization of a eukaryotic expression vector of full-length and mature IL-37b / 中国比较医学杂志

Objective To construct a eukaryotic expression vector pEGFP N1/IL-37b of full-length and mature IL-37b,and to detect the expression of both full-length and mature IL-37b in RAW 264.7 cells, a mouse macrophage cell line. Methods To construct the eukaryotic vectors of full-length and mature IL-37b by using plasmid pUBC/IL-37b as a template containing the coding region of IL-37b full-length gene. To detect the expression of IL-37b by western blot and confocal microscopy after transfected the recombinant plasmid into RAW 264.7 cells, and to detect the inhibition of full-length and mature IL-37b on IL-6 production by real-time PCR. Results Eukaryotic vectors pEGFP N1/IL-37b expressed full-length and mature IL-37b after transfection in cells, which inhibited LPS-induced IL-6 production. Conclusions Eukaryotic vectors of full-length and mature IL-37b can be successfully constructed,and lays a foundation for further study of anti-inflammation functions and mechanisms of IL-37b.

Effects of FoxO1 on FoxO1-KLF2-S1P1 pathway in Jurkat cells / 中国免疫学杂志

To observe the contribution of FoxO1 on its downstream molecules expression and function in Jurkat cells,Jurkat cells were infected with FoxO1 expression lentivirus and interference lentivirus to establish FoxO1-KLF2-S1P1 signaling pathways mod-el.After infection of 120 h,FoxO1,KLF2,S1P1 and CD62L mRNA levels and the protein expression of FoxO1,FoxO1-p and KLF2 were increased (P<0.05) in FoxO1-overexpression group.Converse results(P<0.05) were observed in the interference group.The proportions of S1P1+cells were increased in both groups.It was notably that S1P1+cells were decreased(P<0.05) in interference group after infection of 72 h.The proportion of CD62L+cells was increased(P<0.05) in overexpression group,it was decreased(P<0.05) in the interference group.This vitro experiments showed S1P1 and CD62L could be regulated by FoxO1 lentivirus,and provided an experimental basis for research about intracellular FoxO1-KLF2-S1P1 signaling pathways and cellular functions.

Improving the expression of recombinant pullulanase by increasing mRNA stability in Escherichia coli

Background: Pullulanase production in both wild-type strains and recombinantly engineered strains remains low. The Shine-Dalgarno (SD) sequence and stem-loop structure in the 5' or 3' untranslated region (UTR) are well-known determinants of mRNA stability. This study investigated the effect of mRNA stability on pullulanase heterologous expression. Results: We constructed four DNA fragments, pulA, SD-pulA, pulA-3t, and SD-pulA-3t, which were cloned into the expression vector pHT43 to generate four pullulanase expression plasmids. The DNA fragment pulA was the coding sequence (CDS) of pulA in Klebsiella variicola Z-13. SD-pulA was constructed by the addition of the 5' SD sequence at the 5' UTR of pulA. pulA-3t was constructed by the addition of a 3' stem-loop structure at the 3' UTR of pulA. SD-pulA-3t was constructed by the addition of the 5' SD sequence at the 5' UTR and a 3' stem-loop structure at the 3' UTR of pulA. The four vectors were transformed into Escherichia coli BL21(DE3). The pulA mRNA transcription of the transformant harboring pHT43-SD-pulA-3t was 338.6%, 34.9%, and 79.9% higher than that of the other three transformants, whereas the fermentation enzyme activities in culture broth and intracellularly were 107.0 and 584.1 times, 1.2 and 2.0 times, and 62.0 and 531.5 times the amount of the other three transformants (pulA, SD-pulA, and pulA-3 t), respectively. Conclusion: The addition of the 5' SD sequence at the 5' UTR and a 3' stem-loop structure at the 3' UTR of the pulA gene is an effective approach to increase pulA gene expression and fermentation enzyme activity.

Construction of rat beta defensin-2 eukaryotic expression vector and expression in the transfected rat corneal epithelial cell / 国际眼科杂志(Guoji Yanke Zazhi)

@#AIM: To construct a recombinant eukaryotic expression vector of rat beta defensin-2(rBD-2), transfect it into the rat corneal epithelial cells with lipofection, determine the expression of target gene in the transfected cells, and discuss the potentiality of recombinant plasmid expressed in corneal epithelial cells, hoping to provide an experimental foundation for further study on the antimicrobial activity of rBD-2 <i>in vitro </i>and <i>in vivo</i> and to assess the probability of defensins as a new application for infectious corneal diseases in the future. <p>METHODS: The synthetic rBD-2 DNA fragment was inserted between the <i>Xho</i>I and <i>BamHI</i> restriction enzyme cutting sites of eukaryotic expression vector pIRES2-ZsGreen1 to construct the recombinant plasmid pIRES2-ZsGreen1-rBD-2, then transformed it into <i>E.coli DH5α</i>, positive clones were screened by kanamycin and identified with restriction endonucleases and sequencing analysis. Transfection into the rat corneal epithelial cells was performed by lipofection. Then the experiment was divided into three groups: rat corneal epithelial cell was transfected with the recombinant plasmid pIRES2- ZsGreen1-rBD-2, rat corneal epithelial cell was transfected with the empty plasmid pIRES2-ZsGreen1 and the non-transfected group. The inverted fluorescence microscope was used to observe the transfection process. At last, the level of rBD-2 mRNA expressed in the transfected cells and the control groups are compared by the real-time fluoresence relative quantitative PCR. <p>RESULTS: The recombinant eukaryotic expression vector of pIRES2-ZsGreen1-rBD-2 was successfully constructed. The level of rBD-2 mRNA in transfected cells was significantly higher than that in control groups through the real-time fluorescence relative quantitative PCR. <p>CONCLUSION: The recombinant eukaryotic expression vector pIRES2-ZsGreen1-rBD-2 could be transfected into rat corneal epithelial cells, and exogenous rBD-2 gene could be transcripted into mRNA in the transfected cells.

Cloning of full-length cDNA of gene encoding dihydrodipicolinate synthase from Carthamus tinctorius and construction of plant expression vector / 中草药

Objective: To clone the full-length cDNA sequence of DHDPS gene encoding the key enzyme DHDPS in lysing biosynthesis pathway of Carthamus tinctorius, and to construct the plant expression vector. Methods: The dihydrodipicolinate synthase (DHDPS) gene fragment was acquired according to the sequence of transcriptome in C. tinctorius, and the full-length cDNA sequence of CtDHDPS gene from C. tinctorius seeds was cloned by RT-PCR and RACE technologies. The pBasta-DHDPS plant expression vector was constructed using traditional molecular cloning and recombination technique. Results: Bioinformatics analysis showed that the full-length cDNA of CtDHDPS was 1309 bp, open reading frame was 954 bp, encoding a polypeptide of 317 amino acids, the theoretical isoelectric point of the coded protein was 5.93, and the molecular weight was about 34 750.79. The plant expression vector pBasta-DHDPS was successfully constructed by traditional molecular cloning and recombinant technique. Conclusion: The full-length sequence of CtDHDPS gene is obtained and the plant expression vector is successfully constructed, which lays a foundation for the further study on the mechanism of CtDHDPS in regulation of essential amino acid metabolism.