As an effective vehicle for bio-research and for gene therapy, Lentiviral Vector (LV) has been drawn large attention in recent years. However, transcriptional read-through limits its application. In order to understand the extend of LV read-through in chromosome, a reliable method to assess transcriptional read-through rate is needed. Here, we report the method as follows: 293T cells were transfected with the lentiviral transfer vectors which borne with two LTRs at its two ends in order to mimic the state of "proviral vectors" in chromosome. Using the primers specific for 3'U5 and 3'U3, read-through and total transcripts were reverse transcribed, respectively. These two cDNAs were quantified by realtime PCR using the primers and probe specific for 5'end of 3'U3. Read-through rate was then calculated by the division of the two. Meanwhile, read-through product of green fluorescence protein was also analyzed by Fluorescence Activated Cell Sorter. They both reciprocally proved the principal and confirmed that self-inactivated LV appeared higher read-through rate than the wild type one. The method described in this article, therefore, provides a useful technique to study how to reduce read-through rate, and improve the bio-safety of LV.
Flow Cytometry ; Genetic Therapy ; Genetic Vectors ; Green Fluorescent Proteins ; biosynthesis ; HEK293 Cells ; Humans ; Lentivirus ; Transfection

OBJECTIVETo investigate the influence of fluorescent protein expression on the proliferation of murine NIH3T3 cells, so as to provide a theoretical basis for cell tracing technology.

METHODSNIH3T3 cells were cultured in vitro, and were randomly divided into control, pLEGFP-N1 (with transfection of pLEGFP-N1 retroviral vector), pEGFP-N1 (with transfection of pEGFP-N1 vector) and pDsRed2-C1 (with transfection of pDsRed2-C1 vector) groups. Then the cells were screened by G418 for 3 weeks. The changes in cell adhesive rate were observed and the population doubling times was determined by growth curve.

RESULTSThere was obvious fluorescent protein expression in the transfected NIH3T3 cells after G418 selection, and the highest percentage of labeled NIH3T3 cells was found in pLEGFP-N1 group. The population doubling time in pDsRed2-C1 (40.3+/-0.7 h) , PEGFP-N1 (39.6 +/- 0.6 h) and pLEGFP-N1 (36.5 +/- 0.7 h) groups was evidently longer than that in control (27.9 +/- 0.6 h, P < 0.01), with high adhesive rate in each group.

CONCLUSIONThe expression of fluorescent protein exhibited some inhibitory effect on the proliferation of NIH3T3 cells in vitro. Since the inhibitory effect by retroviral vector was weaker compared with eukaryotic vector, it should be the first choice for fluorescent protein labeling during cell transplantation.

Animals ; Cell Culture Techniques ; Cell Proliferation ; Green Fluorescent Proteins ; biosynthesis ; Mice ; NIH 3T3 Cells ; Transfection

Laser scanning confocal microscope (LSCM) is currently the only equipment to observe fluorescence. However, this technique has disadvantages such as high cost and long test process. In this study, we developed a new system of laser-induced fluorescence (LIF) for microfluidic chip applied to detecting the expression of green fluorescent protein (GFP) in Bacillus subtilis. This novel system was comprised of laser device, optics unit, microfluidic chip, photomultiplier and computer treatment unit. The tests indicated that microfluidic chip could detect the expression of GFP as sensitively as LSCM in Bacillus subtilis. Moreover, this LIF detection system could instead of PCR to identify the positive clone in this special case. Nevertheless, the LIF system only was suitable to detect the fluorescent strength of GFP, and could not meet the request of some cases for example protein location. Therefore, this system will be applied in environmental detection with microbe, drug discovery and other cases.
Bacillus subtilis ; isolation & purification ; metabolism ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Microfluidic Analytical Techniques ; methods

Based on site-specific transposition of an expression cassette into a baculovirus shuttle vector (Bacmid) which propagated in Escherichia coli, the Bac-to-Bac System provides a rapid and efficient method to generate recombinant baculoviruses and is widely used for high level expression of heterologous proteins. And the efficiency of recombinant baculovirus infecting cells plays an important role on the protein expression. In this study, we introduced an EGFP expression cassette driven by polyhedrin promoter into the p74 locus of Bacmid by homologous recombination. The target Bacmid-egfp was then transformed into E. coli DH10B containing the transposition helper plasmid to gain a new transposition receipt strain E. coli DH10Bac-egfp. Because of the intact attTn7 sites and lacZ', target gene cloned in a pFastBac vector can be transposed into the Bacmid-egfp shutter vector to construct recombinant baculovirus, which would allow the tracing of the target protein expression and the recombinant Bacmid transfection or recombinant baculoviral infection under fluorescence microscopes. Recombinant virus Bac-egfp-DsRed was constructed by transposing DsRed into the Bacmid-egfp in E. coliDHl0Bac-egfp, and the Sf9 cells infected with the recombinant virus expressed DsRed and EGFP efficiently. Another protein IL-6 fused with 6 x his tag was expressed and purified sucessfully from Sf9 cells infected with recombinant virus Bac-egfp-6 x his-IL6 constructed by the improved Bac-to-Bac system.
Animals ; Baculoviridae ; genetics ; Green Fluorescent Proteins ; genetics ; Interleukin-6 ; biosynthesis ; genetics ; Plasmids ; Polymerase Chain Reaction ; Recombinant Proteins ; biosynthesis ; Spodoptera

For studying the effects of Mycobacterium tuberculosis secretory protein ESAT-6 on the related functions of macrophages, RAW264.7 cells were transfected with pEGFP-C1-ESAT-6 and pEGFP-C1 by liposome respectively. After screening with a high level of G418, the macrophage cell lines that stably expressed EGFP-ESAT-6 fusion protein or EGFP were established. The gene and protein expression levels were further analyzed by RT-PCR, fluorescence microscopy and Western blotting. The results indicated that the EGFP-ESAT6 fusion gene was integrated into the chromosome and the protein could be stably expressed in the selected macrophage cell line. These results gave us a tool for the future study in the mechanisms of ESAT-6 protein in modulating the macrophage cells.
Animals ; Antigens, Bacterial ; biosynthesis ; genetics ; Bacterial Proteins ; biosynthesis ; genetics ; Cell Line ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Macrophages ; cytology ; metabolism ; Mice ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Transfection

OBJECTIVE: To analyze the expression and location of coding protein of UBAP1 gene and to understand the relationship between the expression pattern of the protein and cell carcinogenesis. METHODS: Bioinformatics was used to analyze the protein character to provide an available clue of subsequent research. The codon frame cDNA was amplified by PCR, and subcloned into enhance green fluorescence protein (EGFP) of pEGFP-C2. The recombinant plasmid was transfected into HNE1 cells. The expression of coding protein was observed by fluorescence microscopy. RESULTS: The expressed GFP-fusion protein generated striking green fluorescence in the cytoplasm in HNE1 cells. EGFP/UBAP1 was expressed and existed mainly in the nuclear, especially accumulated on the nuclear envelope. CONCLUSION The expression difference in HNE1 might be related to the carcinogenesis of NPC.
Base Sequence ; Carrier Proteins ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Humans ; Molecular Sequence Data ; Nasopharyngeal Neoplasms ; metabolism ; Neoplasm Proteins ; biosynthesis ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection

Spore coat proteins, such as CotB, CotC, CotG et al, are able to efficiently display exogenous protein on spore surface for preparing oral vaccines or enzymes. CotX is another structural protein of spore coats of Bacillus subtilis. To investigate whether CotX could carry target protein onto the spore surface, we constructed a recombinant integrative plasmid, designated as pJS749, which carries a recombinant cotX-gfp gene under the control of the cotX promoter. We transformed pJS749 into Bacillus subtilis 168(trp-), an alpha-amylase inactivated mutant DRJS749 was selected and confirmed to be a double crossover integrant, where cotX-gfp fragment was integrated into the chromosome. After induction of spore formation, significant green fluorescence was observed on spore surface of strain DRJS749 under fluorescent microcopy. This suggests that CotX is associated with the outer part of the coat. CotX can therefore be used as a molecular vehicle for spore surface display of exogenous proteins.
Bacillus subtilis ; genetics ; metabolism ; physiology ; Bacterial Proteins ; biosynthesis ; genetics ; Gene Expression Regulation, Bacterial ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; Spores, Bacterial ; genetics ; metabolism

We constructed the recombinant adenovirus expressing the glycoprotein G2 of Hantaan virus. Firstly we obtained coding gene fragment of G2 by PCR, and subsequently inserted the gene of interest into the Adenoviral pShuttle vector pAd5-CMV. Then we co-transfected the recombinant pShuttle vector and adenovirus skeleton plasmid into HEK293 cells by Calcium phosphate precipitation method. After the recombinant adenovirus were packaged and amplified in HEK293 cells, we observed the expression of reporter gene eGFP by fluorescent microscopy, and we obtained the recombinant adenovirus containing Hantaan virus glycoprotein G2. The recombinant adenoviruses were used to infect Hela cells and the expressed protein was detected by Indirect Immuno-fluorescence and Western blotting. The construct was confirmed at several levels: first restriction enzyme analysis demonstrated that the recombinant adenovirus vector was constructed correctly, second RT-PCR showed that the G2 gene could transcribe correctly in Hela cells. Then Fluorescent microscopy proved the expression of eGFP in the infected Hela cells. Finally, Indirect Immune-fluorescence and Western-blot confirmed the expression of interested protein identified by anti-G2 monoclonal antibody. In conclusions, this study successfully constructed the recombinant adenovirus containing Hantaan virus envelope glycoprotein G2, meanwhile obtained the G2 protein, it may lay solid foundation for the structure study of G2 protein and the new vaccine of Hantaan virus.
Adenoviridae ; genetics ; metabolism ; Genetic Vectors ; Green Fluorescent Proteins ; biosynthesis ; genetics ; HEK293 Cells ; HeLa Cells ; Humans ; Kidney ; cytology ; Recombinant Proteins ; biosynthesis ; genetics ; Transfection ; Viral Envelope Proteins ; biosynthesis ; genetics

We cloned genes of four sentrin-specific protease (SENP), three small ubiquitin-like modifiers (SUMO), enhanced cyan fluorescent protein (ECFP) and yellow fluorescent protein (EYFP) by two-step PCR. Then we constructed expression vector B28 for SENP and B13 for ECFP-SUMO-EYFP. The recombinant plasmids were transformed into Escherichia coli BL21 and expression was induced by isopropyl beta-D-thiogalactoside, then recombinant proteins were purified by Ni-NTA agarose column ion-exchange chromatography. The proteins were analyzed with SDS-PAGE and identified with Western blotting. Except that SENP3 catalytic domain (SENP3C) truncated in the C termini and SENP5C expressed in inclusion body, others were expressed as soluble proteins. SDS-PAGE analysis showed that the relative molecular mass of these fusion proteins were consistent with theoretical ones, and the specificity of the fusion proteins were confirmed with Western blotting. The fusion proteins of SENP and ECFP-SUMO-EYFP can be successfully expressed in prokaryotic expression system. It lays the foundation for the fluorescence resonance energy transfer analysis.
Bacterial Proteins ; biosynthesis ; genetics ; Catalytic Domain ; Cysteine Endopeptidases ; biosynthesis ; genetics ; Endopeptidases ; biosynthesis ; genetics ; Escherichia coli ; genetics ; metabolism ; Genetic Vectors ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Humans ; Luminescent Proteins ; biosynthesis ; genetics ; Recombinant Fusion Proteins ; biosynthesis ; genetics ; SUMO-1 Protein ; biosynthesis ; genetics

ObjectiveTo construct a GFP-fused mouse Parkin co-regulated gene (PACRG) baculovirus recombinant PACRG/GFP-pFastBac1 vector and express the fusion protein in Sf9 insect cells.

METHODSFull-length mouse PACRG cDNA was amplified by PCR and cloned in frame to the vector pFastBac1 with eGFP (rpFBac-PACRG-GFP recombinant vector). The plasmid was transformed into DH10Bac cells to obtain the recombinant bacmid plasmid, the bacmid was transfected into Sf9 insect cells, and the expressed PACRG/GFP fusion protein was analyzed by Western blot and fluorescence microscopy.

RESULTSThe construction of the PACRG/GFP-pFastBac1 baculovirus plasmid was confirmed by sequencing and restriction enzyme digestion. Western blot showed the expression of the fusion protein carrying a green fluorescence in the Sf9 insect cells.

CONCLUSIONSConclusion: A PACRG/GFP-pFastBac1 recombinant baculovirus vector was successfully constructed and the fusion protein was highly expressed in the Sf9 insect cells. Our findings have provided a basis for further studies on the structure of the PACRG protein and regulation of spermatogenesis.

Animals ; Baculoviridae ; Blotting, Western ; DNA, Complementary ; Genetic Vectors ; Green Fluorescent Proteins ; biosynthesis ; Mice ; Plasmids ; Polymerase Chain Reaction ; Proteins ; genetics ; metabolism ; Recombinant Fusion Proteins ; biosynthesis ; Sf9 Cells ; Transfection