83 results about "Multiple cloning site" patented technology

The invention discloses a double-fluorescence-labeled engineering bacterium for in-situ tracing of horizontal transfer of plasmids in pseudomonas among bacteria as well as a construction method and application of the double-fluorescence-labeled engineering bacterium, pseudomonas is taken as an original strain, a green fluorescence strong expression component is integrated into a pseudomonas chromosome genome, and green fluorescence-labeled pseudomonas is obtained; a red fluorescence strong expression element is inserted into a multiple cloning site of a broad-host zygote, and is converted into the green fluorescence labeled pseudomonas to form a double-fluorescence labeled engineering bacterium. The double-fluorescence-labeled strain disclosed by the invention can generate corresponding green fluorescence or red fluorescence after being excited by a green or red fluorescence excitation wavelength; when the plasmids enter other bacteria under the action of conjugation or transformation, the recipient bacteria can only present red fluorescence under the excitation of the red fluorescence excitation wavelength, and the horizontal transfer condition of the plasmids in the pseudomonas bacteria among the bacteria under the in-situ condition can be accurately tracked through the intuitive method.

The invention provides an hpRNA interference vector for laver and application of the hpRNA interference vector, and belongs to the technical field of genetic engineering and algae biology. According to the hpRNA interference vector, a binary vector pBI121 is used as a skeleton vector, a laver endogenous Actin promoter and a multiple cloning site segment are inserted, the multiple cloning sites allow target gene segments to be cloned in a forward and reverse repetition mode, the target gene segments are spaced by introns, and therefore an efficient hpRNA structure is formed after transcription, and the efficient hpRNA interference vector is obtained. The gene can be directly used for silencing important genes related to growth and development, metabolic regulation, stress response and the like in the laver. The invention further provides a construction method of the hpRNA interference vector and application of the hpRNA interference vector in silencing laver genes and provides a method for silencing laver gene expression, the gene silencing effect is remarkable, experimental results can be repeated, and a powerful tool is provided for molecular breeding and genetic improvement of laver.

The invention belongs to the field of genetic engineering and biological catalysis, and discloses carboxylase, engineering bacteria and application of the carboxylase in production of aromatic carboxylic acid. The invention discloses a strain of escherichia coli expressing a carboxylase coding gene from marinicaulia flavus, and a construction method of the escherichia coli comprises the following steps: inserting a target protein carboxylase coding gene into a multiple cloning site of a vector pET-28a (+), so as to obtain a recombinant plasmid pET28a-CW354; and introducing the recombinant plasmid into escherichia coli BL21 (DE3) to obtain the engineering bacterium. The invention also protects a method for producing aromatic carboxylic acid, the carboxylase can be used for carboxylating aromatic phenols obtained by depolymerizing lignin, has a wide substrate spectrum, does not need high temperature and high pressure in the whole process, and has the advantages of mild conditions, simplicity in operation, environmental friendliness and the like.

The invention discloses a method for constructing an engineered bacterium of Clostridium aeruginosa, comprising the following steps: preparing a desired gene in a biosynthetic pathway of a target product, namely a pathway gene, to form a pathway gene cluster; embedding the pathway gene cluster into a transposase recognition site of a mariner transposon to form a pathway gene expression cassette; selecting a constitutive strong promoter commonly used in Clostridium jundal for driving transposase expression, loading the pathway gene expression cassette into a multiple cloning site of a plasmid, and inserting an inducible repressor element upstream of the replicon to obtain a transposition plasmid; transforming the transposition plasmid into Clostridium aeruginosa to obtain an engineered bacterium of Clostridium aeruginosa. The yield of 3-hydroxybutyric acid expressed by the engineered bacterium constructed by the above method is as high as 3g / L.

The invention discloses an escherichia coli-bacillus subtilis shuttle plasmid and application, and belongs to the field of gene engineering. The shuttle plasmid comprises the following elements: a promoter sequence, a coding sequence of bacillus subtilis signal peptide, a replication initiation sequence of bacillus subtilis, a replication initiation sequence of escherichia coli and an antibiotic resistance gene. According to the plasmid design, a modular structure is adopted, and quick replacement of key elements such as a promoter, a signal peptide and RBS is supported through optimized enzyme cutting site layout; a 6 * His tag introduced at the tail end of a multiple cloning site (MCS) can be adapted to nickel column affinity chromatography, and the purification process of the recombinant protein is simplified. The plasmid has the characteristics of small molecular weight and convenience in operation, can be efficiently cloned and constructed in escherichia coli and then directly converted into bacillus subtilis for protein expression, is particularly suitable for development of a gram-positive bacterium secretory expression system, and provides an efficient tool for large-scale production of industrial enzyme preparations.

An uropathogenic escherichia coli recombinant protein composition LS, a construction, expression and purification method therefor, and a use thereof, relating to the technical field of genetic engineering. The method comprises: carrying out PCR amplification on LpcA and SurA genes, and respectively inserting the LpcA and SurA genes into multiple cloning sites of a cloning vector to construct a recombinant vector; then converting the recombinant vector into an escherichia coli expression protein; and finally, carrying out purification to obtain a composition LS of an LpcA protein and an SurA protein, wherein the composition LS can be used in a urinary tract infection vaccine. The present invention has the following advantages: a protein vaccine can induce relatively strong cell and humoral immune response of animals; and animal challenge experiments show that the protein vaccine has the protection effect of reducing the bacterial loads of the bladder and the kidney.

The present invention discloses a method for constructing acid-resistant engineered algae, belonging to the fields of biology and molecular biology. The specific method is as follows: Using Phatr3_J33543 with the sequence structure shown in SEQ ID No.1, Phatr3_J50516 with the sequence structure shown in SEQ ID No.2, or Phatr3_Jdraft1806 with the sequence structure shown in SEQ ID No.3 as the target gene, removing the stop codon of the target gene, and connecting the fluorescent protein gene without the start codon through the DNA sequence encoding glycine to obtain a recombinant gene; inserting the recombinant gene into the multiple cloning site of the pPhaNR plasmid to obtain a vector plasmid; introducing the vector plasmid into diatom cells by electroporation and then inoculating them onto the ESAW solid selection medium containing bleomycin, and growing brown colonies; selecting the colonies with fluorescent protein signals in the colonies, which are the acid-resistant engineered algae. Compared with the wild algal species, the acid-resistant ability of the engineered algae obtained by the present invention is significantly improved. The present invention has important reference significance for the cultivation of acid-resistant diatoms.

The present application relates to the field of genetic engineering, and in particular to a vector for analyzing plant promoter expression specificity, a preparation method and application thereof. The T-DNA region of the vector comprises, from 5' end to 3' end, a callus-specific promoter-driven selection marker gene expression cassette and a reporter gene expression cassette with a multiple cloning site; the callus-specific promoter-driven selection marker gene expression cassette comprises a callus-specific promoter, a selection marker gene coding sequence and a terminator. The vector of the present application utilizes a rice callus-specific promoter to drive the expression of a selection marker gene, can greatly reduce the non-specific interaction with the promoter of a target gene, improve the specificity of the expression of the target gene, and effectively reduce the biological safety risk caused by the selection marker gene in a transgenic plant, and has important application value in basic theoretical research and molecular breeding.

The application provides a construction of a fluorescent protein labeled microtubulin and a microtubule binding protein universal bivalent carrier, and the process is as follows: a first stage is to construct a GFP-alpha tubulin carrier, and a second stage is to construct a GFP-alpha tubulin-mCherry universal bivalent co-expression carrier; in the second stage, 35S, mCherry and NOS sequences are inserted into a KpnI enzyme cutting site of a multiple cloning site of the GFP-alpha tubulin carrier constructed in the first stage, and a single nucleic acid enzyme cutting site is inserted into the 5' end and the 3' end of the mCherry sequence, respectively, and the single nucleic acid enzyme cutting site is XbaI, KpnI / Acc65I and AscI sequences, respectively, so as to obtain the universal bivalent carrier. The universal bivalent carrier provided by the application can express two target genes simultaneously, has the fluorescent signals of GFP and mCherry, can quickly and accurately identify a transgenic plant, is convenient for positive seedling screening, can be used for a tobacco transient expression experiment, can shorten an experimental period, and saves time and effort.

The invention discloses a method for expressing a specific domain of a Mouse SPO11 protein. The method comprises the following steps: using a sequence of the Mouse SPO11 protein as a template, designing primers for PCR amplification, and obtaining a Mouse SPO11 gene fragment after PCR amplification; in an Alp_PET_StHis_SUMO empty vector, sequentially designing a Strep tag II affinity tag, an 8x his affinity tag, and a SUMO solubilizing tag at the N-terminus of a multiple cloning site; subjecting the Mouse SPO11 gene fragment after PCR amplification to gel electrophoresis, followed by gel excision recovery, and then simultaneously subjecting the Mouse SPO11 gene fragment to BamHI and EcoRI double enzyme digestion with the expression vector Alp_PET_StHis_SUMO, and then subjecting the Mouse SPO11 gene fragment to gel excision recovery, connection, transformation, colony PCR, colony culture, and plasmid extraction to obtain a successfully constructed plasmid; inducing expression of the plasmid to obtain an expressed bacterial solution; and purifying the expressed bacterial solution to obtain the Mouse SPO11 protein specific domain. The invention can express the specific structural domain of Mouse SPO11 protein and obtain high-purity Mouse SPO11 protein.

The invention discloses a preparation method and application of a biological herbicide based on an RNA (Ribonucleic Acid) interference technology, which specifically comprises the following steps: designing a specific siRNA (Small Interference Ribonucleic Acid) sequence through a targeted glutamine synthetase gene (GS2), cloning a reverse repeat structure of the specific siRNA sequence to multiple cloning sites of an L4440 vector, and transforming the reverse repeat structure to RNase III defective escherichia coli HT115 for induced fermentation. By optimizing IPTG concentration and induction time, the thalli efficiently express target dsRNA, and a dsRNA aqueous solution is prepared after splitting decomposition and purification. Foliage spraying is adopted during spraying treatment, dsRNA can permeate into plant cells through pores, GS2 mRNA is specifically degraded, ammonium ions in the cells are accumulated, a photosynthetic system collapses, and leaves wither, wither and yellow and finally die within 72 hours. Compared with a traditional chemical herbicide, the herbicide has the advantages of being accurate in targeting, safe, environmentally friendly, free of residues and the like, and an efficient and sustainable biological solution is provided for agricultural weeding.

The invention discloses a high-efficiency expression and purification method of 5 '-3' exonuclease, which comprises the following steps: based on a Bac-to-Bac system, adding a tag and a TEV restriction enzyme cutting site to optimized 5 '-3' exonuclease Xrn1, then connecting the 5 '-3' exonuclease Xrn1 to a multiple cloning site behind a Polyhedrin promoter of a pFastBac expression vector to prepare expression baculovirus plasmids, and carrying out purification on the expression baculovirus plasmids to obtain the 5 '-3' exonuclease. Then transfecting the recombinant baculovirus particles into insect cells to generate recombinant baculovirus particles; finally, the 5 '-3' exonuclease Xrn1 is obtained through nickel column affinity chromatography, Heparin affinity chromatography and gel filtration chromatography purification, the invention provides a more economical and practical technical route for synthesizing the 5 '-3' exonuclease Xrn1, and a technical foundation is laid for large-scale production of the 5 '-3' exonuclease.

This invention relates to genetic engineering technology and aims to provide a method for preparing and applying bacteriophage capsid protein MS2-armored PRRSV antigen mRNA particles. The method includes: inserting the MS2 bacteriophage capsid protein gene and an mRNA expression cassette into a double multiple cloning site expression vector; transforming the recombinant expression plasmid into host bacteria; inducing expression to allow the MS2 capsid protein to express and self-assemble into virus-like particles; utilizing the specific recognition of the MS2 capsid protein on the packaging stem-loop structure, packaging the transcribed mRNA inside the virus-like particles to form MS2-armored PRRSV antigen mRNA particles; lysing the host bacteria, separating the supernatant, and enriching and purifying the particles. This invention significantly enhances the resistance of mRNA to nuclease degradation and improves formulation stability; it can increase the efficiency of mRNA entering antigen-presenting cells and enhance immunogenicity; it can be mass-produced with controllable processes and relatively low cost.

The invention discloses a multi-reporter gene expression cassette for plant promoter expression pattern and activity analysis, the expression cassette sequentially comprises a multiple cloning site MCS and a terminator from 5'end to 3 'end, at least two reporter genes are arranged between the MCS and the terminator, and the adjacent reporter genes are spaced by a 2A sequence, the reporter genes are different types of reporter genes, the types of the reporter genes include but are not limited to fluorescent protein reporter genes and enzyme reporter genes, the 2A sequence is a 2A self-cleavage peptide sequence, and the terminator has the capability of terminating transcription started by the Pol II type promoter. The MCS in the expression cassette facilitates cloning of various promoters and other functional elements, and the expression cassette contains fluorescent protein reporter genes and enzyme reporter genes at the same time, has the advantages of the fluorescent protein reporter genes and the enzyme reporter genes, and has the advantages of being wide in application range and diverse in detectable means.

The invention discloses an alkali-resistant application of a soybean GmNPF7.13 gene. The nucleotide sequence of the soybean GmNPF7.13 gene is as shown in SEQ ID NO. 1. The plant GmNPF7.13 gene silencing vector comprises a recombinant GmNPF7.13 gene silencing vector, the gene GmNPF7.13 segment is inserted into multiple cloning sites of a no-load VIGS-EV of the silencing vector, and GmNPF7.13 gene silencing is realized in a plant. According to the invention, two independent verification systems, including two mutants and a virus-induced GmNPF7.13 gene silencing material, both show enhanced alkali resistance and are strong in verification consistency. The GmNPF7.13 gene disclosed by the invention not only facilitates analysis of a response mechanism of soybeans to alkali stress, but also can be used as a target gene for creating alkali-resistant plants and expanding planting of the soybeans in soda saline-alkali soil, and has important theoretical significance and breeding application prospects.

The invention provides a method for prokaryotically expressing cat allergen Fel d 1 recombinant protein, which comprises the following steps of: cloning a cat allergen Fel d 1 gene to multiple cloning sites of an expression vector pGEX-4T-1 to obtain a recombinant expression vector pGEX-4T-1-Fel d 1, transforming the recombinant expression vector into escherichia coli Rosetta (DE3) competent cells to construct recombinant engineering bacteria pGEX-4T-1-Fel d 1 / Rosetta (DE3), and carrying out prokaryotic expression on the recombinant engineering bacteria pGEX-4T-1-Fel d 1 / Rosetta (DE3) to obtain the cat allergen Fel d 1 recombinant protein. IPTG (isopropyl-beta-d-thiogalactoside) is used for inducing protein expression, and a GST affinity chromatography medium is used for capturing high-purity soluble GST-Fel d 1 fusion protein. According to the invention, a pGEX-4T-1-GST label system is combined with Escherichia coli Rosetta (DE3), so that the problem of soluble expression of the cat allergen Fel d 1 protein is fundamentally solved.

The invention relates to the technical field of biomedicine, and particularly discloses a dynamic monitoring method for ATP (adenosine triphosphate) level in cardiac muscle cells, recombinant cardiac muscle cells and application. The preparation method comprises the following steps: cloning an iATPSnFRs gene as shown in SEQ ID NO.3 into multiple cloning sites of a pLVX-AcGFP1-N1 plasmid, so as to construct an iATPSnFR1 recombinant plasmid; then transfecting myocardial cells with the iATPSnFR1 recombinant plasmid to obtain recombinant myocardial cells; and monitoring the ATP level change in the iATPSnFR1 recombinant myocardial cells in real time by using a high content imaging system. The recombinant myocardial cell containing the iATPSnFR1 is obtained through construction, so that the iATPSnFR1 can be specifically combined with ATP in the cell and generate a fluorescence signal, real-time and dynamic monitoring of the ATP level can be realized, and the recombinant myocardial cell has the advantages of non-invasiveness, high spatial resolution and the like.

The present invention belongs to the field of genetic engineering and molecular biology, and specifically relates to a simple, fast and efficient method for constructing an RNA interference vector and its application. The method specifically includes designing specific primers with homology arms and restriction sites, amplifying exogenous DNA fragments using the specific primers, and using restriction endonucleases to Bam HI and Kpn Ⅰ Enzyme cut the RNA interference empty vector, and use the homologous recombination method to connect the exogenous DNA fragment to the RNA interference empty vector to form the RNA interference final vector. This method introduces a lethal gene on the RNA interference backbone vector. Combined with the homologous recombination method, only one homologous recombination is needed to simultaneously connect two exogenous DNA fragments into the two multiple cloning sites of the RNA interference vector, which greatly shortens the RNA interference vector construction cycle, and the vector construction positive rate reaches 100%. In addition, the selection of exogenous fragments is no longer limited by the restriction site, and can be freely selected, which broadens the range of targets.

The invention discloses an acid-resistant microalgae construction method based on bicarbonate ion transporter protein, and belongs to the field of biology and molecular biology. The method specifically comprises the following steps: taking Phatr3J33543 with a sequence structure as shown in SEQ ID No.1, Phatr3J50516 with a sequence structure as shown in SEQ ID No.2 or Phatr3Jdraft1806 with a sequence structure as shown in SEQ ID No.3 as a target gene, removing a termination codon of the target gene, and connecting a fluorescent protein gene with an initiation codon removed through a DNA (Deoxyribose Nucleic Acid) sequence for coding glycine to obtain a recombinant gene; inserting the recombinant gene into multiple cloning sites of a pPhaNR plasmid to obtain a vector plasmid; introducing the carrier plasmids into diatom cells through electroporation, and inoculating the diatom cells to an ESAW solid selective culture medium containing bleomycin to grow brown algal colonies; selecting the algal colonies with fluorescent protein signals from the algal colonies, namely the acid-resistant engineering algae. Compared with wild algae, the acid resistance of the engineering algae obtained by the invention is obviously improved. The method has important reference significance on acid-resistant diatom cultivation.

The invention discloses a CAR (chimeric antigen receptor) recombinant lentiviral expression vector suitable for CIK (cytokine-induced killer) cells and NK (natural killer) cells to express EpCAM antibodies, IL-21 and CCL19, and belongs to the technical field of genetic engineering and biology. According to the expression vector, a CAR (chimeric antigen receptor) gene structure, an IL-21 (interleukin-21) gene expression structure and a CCL19 (chimeric antigen receptor 19) gene expression structure are connected between multiple cloning sites Nhe1 and Not1 of a vector pCHD-CMV-MCS-EF1-copGFP-T2A-puro, so that a recombinant plasmid pCDH-21 * 19 EpCAM-CAR is obtained. And transforming the recombinant plasmid into escherichia coli DH5alpha to obtain the recombinant microbial cell. The pCDH-21 * 19 EpCAM-CAR recombinant lentiviral expression vector is packaged, lentiviral particles are concentrated, CIK cells and NK cells are infected, and eukaryote transgenic cells are obtained. The CAR vector aiming at the solid tumor colorectal cancer is constructed, the design of the vector aims at improving the activating and killing capacity of CIK cells and NK cells and solving the problems of tumor microenvironment immunosuppression and the like, and a foundation is further laid for the research of treating solid tumors by applying a CAR technology.

The application discloses a pSY1A plasmid vector for a wheat germ cell-free expression system, which is constructed by introducing an ampicillin resistance gene, an Ori replicon, a T7 promoter, a translation enhancer, a MCS (multiple cloning site), a 3'-UTR sequence and a T7 terminator sequence on the basis of part of a sequence of an E. coli plasmid pUC19. The pSY1A plasmid vector has a MCS into which an exogenous gene can be inserted, and the MCS and a transcription assembly constitute a transcription module, so that the transcription module can be preserved by preserving the plasmid, and in-vitro transcription of the wheat germ cell-free expression system becomes more convenient and faster.

The invention discloses a carrier for localizing a target protein on the surface of a cell membrane, the carrier comprises a Claudin18.2 1-27aa sequence, a PDGFR membrane localization sequence, multiple cloning sites and a gene for coding the target protein, the multiple cloning sites are located between the Claudin18.2 1-27aa sequence and the PDGFR membrane localization sequence, the gene for coding the target protein is inserted into the multiple cloning sites, and the nucleotide sequence of the Claudin18.2 1-27aa sequence is shown as SEQ ID No.6. The invention further discloses a preparation method of the carrier for localizing the target protein on the surface of the cell membrane. The molecular design of the vector fragment can efficiently and quickly locate the protein / polypeptide on the cell membrane surface, does not need to synthesize the full length of the protein, reduces the gene synthesis cost, and can be applied to production of liquid cell quality control products.

The invention discloses an EpCAM gene high expression vector based on a lentiviral vector and a cell strain thereof, and belongs to the technical field of gene engineering and biology. According to the vector, an EpCAM gene expression structure is connected between multiple cloning sites Xba1 and Nhe1 of a vector pCHD-CMV-MCS-EF1-RFP-T2A-puro, high-level expression is carried out under the driving of a CMV (cytomegalovirus) promoter, and a recombinant plasmid pCDH-OE-EpCAM is obtained. And transforming the recombinant plasmid into escherichia coli DH5alpha to obtain the recombinant microbial cell. The recombinant plasmid is respectively transfected with colorectal cancer cell strains HT-29 and HT-115 through a Lipo2000 transfection reagent, and then monoclonal cells are screened, so that transgenic cells are obtained. The vector for overexpression of the human EpCAM gene and the colorectal cancer cell strain for overexpression of the EpCAM gene are constructed, and a very important foundation is laid for molecular mechanism research of generation and development of the EpCAM gene and colorectal cancer.

The invention discloses a pSY1A plasmid vector for a wheat germ cell-free expression system, which is characterized in that on the basis of partial sequence of escherichia coli plasmid pUC19, an ampicillin resistance gene, an Ori replicon, a T7 promoter, a translation enhancer, MCS multiple cloning sites, a 3 '-UTR sequence and a T7 terminator sequence are introduced to construct the plasmid vector pSY1A. According to the pSY1A plasmid vector provided by the invention, the vector has multiple cloning sites into which exogenous genes can be inserted, and the multiple cloning sites and a transcription component form a transcription module, so that the transcription module can be stored by storing plasmids, and the in-vitro transcription of a wheat germ cell-free expression system becomes more convenient and quicker.

A uropathogenic Escherichia coli recombinant protein composition LS, its construction, expression, purification method and application, belong to the field of genetic engineering technology. The present invention performs PCR amplification on LpcA and SurA genes and inserts them into the multiple cloning sites of cloning vectors respectively to construct a recombinant vector; then the recombinant vector is transformed into Escherichia coli to express the protein; finally, purification is performed to obtain a composition LS of LpcA protein and SurA protein, and the composition LS can be used in urinary tract infection vaccines. The advantages of the present invention are that the protein vaccine can induce stronger cellular and humoral immune responses in animals; animal challenge experiments show that it has a protective effect of reducing the bacterial load of bladder and kidney.

The invention belongs to the field of plasmid vector construction, and provides a plasmid vector as well as a construction method and application thereof. The plasmid vector is constructed by modifying pAN7-1, a trichoderma viride promoter gene and a resistance gene are inserted into multiple cloning sites of the pAN7-1 of the plasmid vector, and the resistance gene is located at the downstream of the trichoderma viride promoter gene. According to the invention, the selected trichoderma viride promoter gene segment can efficiently start the gene connected behind, so that the transformation efficiency of the plasmid vector is greatly improved. The invention establishes a method for efficiently transforming trichoderma viride by using an agrobacterium tumefaciens-mediated exogenous gene, and can provide help in the aspects of genetic modification of trichoderma viride, development of useful genes, separation of drug target genes and the like.

The application discloses a gene expression vector pJXNU for actinomycetes, a construction method and application thereof. The sequence of the vector is shown as SEQ ID NO. 2. The vector is based on a pSET152 plasmid, and loaded with kanamycin and thiostrepton antibiotic resistance genes, and a 533bp DNA fragment containing three gene expression element sequences and two sets of multiple cloning sites (MCS) shown as SEQ ID NO. 1. The vector has two autonomously expressed strong gene expression elements and one thiostrepton-induced expression element, can realize autonomous high-efficiency expression of two or two groups of genes and / or induced expression of one or one group of genes on one vector, and can realize multi-type functional gene research and application in an actinomycete host.

The invention discloses a dsRNA fragment capable of improving wheat amylopectin content and a synthesis method and application thereof, and relates to the field of wheat starch content regulation, pET28a is used as an initial skeleton, a sequence containing a reverse T7 promoter, multiple cloning sites and ISA1 or ISA2 gene fragment is inserted, a recombinant vector is constructed through restriction enzyme digestion connection of restriction enzymes SalI and EcoRI, and the recombinant vector is used as a recombinant vector for improving wheat amylopectin content. And transforming the recombinant expression vector into an escherichia coli HT115 competent cell, and synthesizing the dsRNA fragment after induced expression. According to the invention, a non-transgenic transient silencing technology is adopted, and target gene expression is inhibited in a targeted manner, so that the problems of long period, low efficiency, dependence on complex gene cloning and vector construction processes and potential off-target effect and ecological risk existing in the traditional gene technology are avoided.

A method for preparing interaction plasmid library and a method for testing interactions between cDNA libraries are provided. The cDNA libraries could be inserted into the first multiple cloning site and the second multiple cloning site of the dual expression vector for testing the interactions between the different cDNA libraries.

The invention discloses a nucleic acid delivery carrier, a delivery system and application thereof. According to the invention, a CpG sequence is inserted into multiple cloning sites of an eukaryotic expression vector, so that a delivery vector capable of efficiently delivering nucleic acid is constructed, and meanwhile, a nucleic acid delivery system consisting of the delivery vector and probiotics is constructed. On the basis of the delivery vector, nucleic acid to be delivered is inserted into the delivery vector and then transformed into probiotics to construct a recombinant bacterium preparation, namely the nucleic acid to be delivered can be delivered into a body in a manner of orally taking or injecting the recombinant bacterium preparation, so that the defects that only a recombinant expression vector is used for transforming recombinant bacteria, and the efficiency is high are overcome; and nucleic acid is difficult to efficiently deliver into a body. The nucleic acid delivery carrier or delivery system can be used for delivering the nucleic acid with the effect of treating or enhancing the body immunity into the body, that is, the nucleic acid delivery carrier or delivery system can be used for preparing drugs or immune preparations for treating diseases by delivering the nucleic acid, and is wide in application.