Abstract:Angiotensin converting enzyme (ACE, EC 3.4.15.1) is a membrane-bound, zinc dependent dipeptidase that catalyzes the conversion of the decapeptide angiotensin I to the potent vasopressor ocatapeptide angiotensin II, by removing two C-terminal amino acids. ACE is well known as a key part of the renin angiotenisn system that regulates blood pressure, and its inhibitors have potential for the treatment of hypertension. This paper reviewed the characteristics of ACE in aspects of its structure-function relationship, gene polymorphism and inhibitor development. In particular, the catalytic mechanisms of the two active sites of somatic ACE in the cleavage of angiotensinⅠand bradykin are different. Therefore, it would likely provide a new way for exploiting novel ACE inhibitors with fewer side-effects by specifically-targeting the individual active sites of somatic ACE.

Abstract:Diabetes mellitus is a metabolic diseases, mainly including type 1 and type 2 diabetes. Treatment for type 1 and part of type 2 often involves regular insulin injection. However, this treatment neither precisely controls the blood sugar levels, nor prevents the diabetes complications. Transplantation of islets of Langerhans offers an attractive strategy for diabetes therapies, but its wide application has been limited by donor shortage and immunological rejection after transplantation. Stem cells with strong proliferation capacity and multipotential may be potential cell sources in diabetes therapies. For this, adult stem cells are interesting because of absence of teratoma formation and ethnical problems. Adult pancreatic stem cells (PSCs) really exist and could produce insulin-secreting cells both under the condition of pancreatic injury and in vitro culture, but lack of effective markers to enrich PSCs hampers the studies of exploring the expanding and differentiating conditions in vitro. Some other adult stem cells, such as hepatic stem cells, marrow stem cells or intestine stem cells, were also suggested to transdifferentiate into insulin-producing cells under special culture conditions in vitro or by genetic modifications. Moreover, transplanting these adult stem cells-derived insulin-secreting cells into the diabetic mouse could cure diabetes. Thus, adult stem cells would supply the abundant beta-cell sources for cell replacement therapy of diabetes

Abstract:Recombinant expression plasmid of pET-28a (+)-goIL-2 was constructed by inserting the goose IL-2 gene without the signal peptide sequence into the prokaryotic expression vector pET-28a (+), and transformed into the bacterial competent E. coli BL21 (DE3) cells for expression. After IPTG induction, an expected protein band with molecular weight of 15.0 kD was observed on SDS-PAGE gel, recognized by monoclonal antibody against goose IL-2 in western-blotting assay. In the pET-28a (+) expression system, much of the recombinant goose IL-2 (rgoIL-2) was found in inclusion bodies with a portion of soluble protein. The monomer and multimers of soluble goose interleukin 2 proteins were observed in native electrophoresis. The rgoIL-2 proteins were purified by Ni-NTA column under a native condition. The rgoIL-2 soluble protein monomer was isolated by a quick protein isolation and purification system of ?KTA FPLC and identified by native PAGE. Bioactivity analysis showed that the rgoIL-2 monomer stimulated the proliferation of goose lymphocytes in vitro. This will establish a basis for further study about the biological function and clinical application of goose IL-2.

Abstract:The cloned cDNA sequence of rice (Oryza sativa L．Cpslo17) chitinase gene Oschi was cloned, (which was registered in GenBank, the accession number: EU045451) ligated with the expression vector pGEX-4T-1, and transformed into E.coli BL21(DE3). The expression of Oschi was induced by IPTG, and the conditions were optimized. After purification the in vitro activity of Oschi chitinase was analyzed, and the results indicated that it could efficiently degrade chitin.

Abstract:Sef (similar expression to fgf genes) was identified as a feedback antagonist of FGF signaling in zerbrafish, mouse and human. To construct recombinant adenoviral vectors expressing hSef-L and hSef-S, the coding sequences of the two isoforms were amplified and ligated into pAdTrack-CMV, forming shuttle vectors pAdTrack-CMV/hSef-L-Myc and pAdTrack-CMV/hSef-S-Myc. After sequence confirmation, these two shuttle vector plasmids were linearized by Pme I and then co-transformed respectively with the adenoviral genome vector pAdEasy-1 into E. coli BJ5183. The successful recombinants were selected by Kanamycin and confirmed by Pac I digestion. The recombinant vectors Ad-hSef-L-Myc and Ad-hSef-S-Myc were finally digested with Pac I and transfected into HEK293 cells to pack into viral particles. The virus were amplified in 293 cells and used to infect MEF cells. Western blotting analysis was used to demonstrate the expression of hSef-L-Myc and hSef-S-Myc proteins. The inhibitory effects of the adenovirus mediated Sef expression on FGF signaling was further evaluated by Elk luciferase reporter assay. Our results indicated the constructed virus could produce effectively the proteins and then inhibit FGF signaling in MEF cells.

Abstract:With cDNA from Phellodendron amurense seedlings treated with drought stress as tester and cDNA from this plant in normal growth as driver, we construct cDNA subtracted library using suppression subtractive hybridization (SSH). In the library, the rate of recombination was 95%, the size of inserts was 300~800 bp. Two hundred and sixty-five new genes were obtained by DNA sequencing 816 positive clones picked randomly, and partitioned to 16 classes after nucleotide Blast and BlastX homological analysis against NT, NR, SWISSPROT, KEGG database. Forty-four drought stress associated genes, such as heat shock protein cognate 70, dehydration responsive protein 22, universal stress protein, metallothionein II, late embryogenesis abundant protein, were obtained, which made 16.6% of the overall genes. These genes included osmotic regulator, signal component regulatory protein and antioxidant enzyme. The research had established a basis for cloning stress resistance genes and further studying genes expression in P. amurense seedlings under drought stress.

Abstract:Oxalic acid (OA) is inhibitory to many fungal plant pathogens. To further characterize the molecular mechanism of OA involved in fungal pathogenesis, OA insensitive mutants were screened from a chemical inducible Arabidopsis mutant library (about 6000 lines) using MS medium (calcium free) containing 1.2 mmol/L OA and 10 μmol/L estradiol. Harvested putative mutants were collected separately. Individual lines of mutants were screened again on modified MS medium containing OA. Mutants D33, D74, D154, D282 and D630 with enhanced OA resistance were obtained. The T-DNA flanking sequences were amplified by TAIL-PCR. The sequences were blasted against TAIR database. The result indicated that the T-DNA of mutant D33 was inserted between At2g39720 (zinc finger) and At2g39730 (Rubisco activase), and the T-DNA junctions of the other four mutants were the same, all inserted in the same site of the first intron of At5g10450 (14-3-3 protein GF14 lambda).

Abstract:We constructed a recombinant plasmid encoding VP1 gene of O type foot-and-mouth disease virus fused to a molecular adjuvant, goat complement C3d gene. The goat C3d gene was cloned and three copies were tandem-linked with the linker (G4S)2 sequence. VP1 gene of O type foot-and-mouth disease virus was linked to three tandem repeats of C3d through the linker sequence and cloned into pUC19 to obtain the recombinant plasmid pUC19-VP1-C3d3. The VP1-C3d3 fusion gene was then subcloned into the eukaryotic vector pcDNA3.1(+) that had been modified to contain the tissue plasminogen activator (tPA) leader sequence to obtain pcDNA3.1-tPA-VP1-C3d3. HeLa cells were transfected with pcDNA3.1-tPA-VP1-C3d3 by LipofectamineTM 2000. Indirect immunofluorescent assay and Western blot assay showed that VP1-C3d3 fusion gene was successfully expressed in HeLa cells. The fusion protein with the expected size 133 kD could be secreted outside the cells. This study laid a good foundation to further research on the novel vaccine against foot-and-mouth disease virus by using goat C3d as a molecular adjuvant to enhance the immunogenicity of VP1.

Abstract:Porcine interleukin-18 mature protein gene was amplified from porcine spleen cells by RT-PCR. PCR product was cloned into the T vector pGEM-T for sequencing. The nucleotide sequence of this gene was 474 bp. Then, it was subcloned into the prokaryotic expressing plasmid vector pGEX6P-1 and transformed into host E. coli strain BL21 for expression. The expression of pIL-18 mature protein gene was identified by SDS-PAGE .The expression product was fusion protein with molecular weight of 45 kD and the percentage of expression protein in E. coil protein was 28%. The protein was purified by washing of inclusion bodies and the activity was measured by methyl thiazolyl tetrazolium (MTT).

Abstract:Recombinant expression vector pcDNA3-DAFMCP-DP containing human membrane complement regulatory proteins (hCRPs) decay accelerating factor (DAF) and membrane cofactor protein (MCP) cDNA was constructed by using two independent promoters. After transfected into NIH3T3 cells by calcium phosphate-DNA precipitate method, NIH3T3 pcDNA3-DAFMCP-DP transfectants were obtained by G418 selection. Extraneous genes integration was identified by PCR. The co-expression of human DAF and MCP at both mRNA and protein levels was confirmed by using RT-PCR and Western blot analysis. Human DAF and MCP cDNA were integrated into NIH3T3 pcDNA3-DAFMCP-DP genomic DNA after continuous 30 times passages, indicating that NIH3T3 pcDNA3-DAFMCP-DP were stable cell lines. Human C-mediated cytolysis assays showed that NIH3T3 cells transfected stably with pcDNA3-DAF, pcDNA3-MCP, and pcDNA3-DAFMCP-DP were protected from C-mediated damage and co-expressed human DAF and MCP provided more excellent protection against C-mediated attack, which was compared with either DAF or MCP alone. These results suggest that the dicistronic vector could improve the efficiency of multi-gene delivery and benefit the synergic effect of human membrane complement regulatory proteins DAF and MCP.

Abstract:Improving expression of antigen is critical to the immunogenicity of DNA vaccines. To achieve this goal, we modified the NDV F48E9 strain HN gene by optimizing the condon usage and inserting the secretary leader sequence [A/Goose/Guangdong/ 1/96 (H5N1) HA gene, Accession No. AF144305]. The HN gene modified and knocked the signal peptide off were named SoptiHN and optiHN. The three sequence: SoptiHN, optiHN and the NDV F48E9 strain HN gene were inserted into the vector pVAX1 and vector pVAX1-CpG including CpG-ODN sequence respectively. Then we got six recombinant plasmids: pV-SoptiHN, pVC-SoptiHN, pV-optiHN, pVC-optiHN, pV-HN and pVC-HN. By optimizing condon usage in transiently transfected 293T cells, expression levels of HN gene were higher from the codon-optimized gene than the counterpart. Moreover, both optimization of condon usage and addition of signal peptide could improve expression of HN gene in vitro.

Abstract:Metagenomic cosmid libraries containing 1.26×105 clones, covering about 4.8×106 kb metagenomic DNA of uncultured microorganisms from the contents of buffalo rumens were constructed, and 118 independent clones expressing b-glucosidase activity were isolated from the libraries. Screening of these clones showed that eight clones expressed relatively higher b-glucosidase activity at pH 5.0 and 37℃. One out of the eight clones was subcloned. Sequencing analysis showed that an open reading frame (ORF) of 2223 bp, termed umcel3G, potentially encodes a b-glucosidase. The encoded product shared highest homology with a b-glucosidase from Bacillus sp. at 60% identity and 73% similarity. The umcel3G was over-expressed in Escherichia coli and the size of the translated product Umcel3G on SDS-PAGE was in agreement with the predicted molecular mass. Zymogram analysis showed that Umcel3G exhibited b-glucosidase activity, confirming that this ORF encodes a b-glucosidase. The Umcel3G, purified with Ni-NTA column, exhibited optimal activity at pH 6.0~6.5 and 45oC. Certain ions such as Ca2+, Zn2+ had significant positive effect on the activity of Umcel3G. However, some ions such as Fe3+, Cu2+ gave significant inhibitory effect on the enzyme. The Ni-NTA purified recombinant b-glucosidase Umcel3G had a specific activity of 22.8 IU/mg at pH4.5, 35oC and at the presence of 5 mmol/L Ca2+, indicating that this enzyme has potential applications in the fermentative production of ethanol by simultaneous saccharification and cofermentation (SSCF) of lignocelluloses.

Abstract:A cDNA, named Dd-ace-2, encoding an acetylcholinesterase (AChE , EC3.1.1.7), was isolated from sweet-potato-stem nematode, Ditylenchus destructor. The nucleotide and amino acid sequences among different nematode species were compared and analyzed with DNAMAN5.0、MEGA3.0 softwares. The results showed that the complete nucleotide sequence of Dd-ace-2 gene of Ditylenchus destructor contains 2425 base pairs from which deduced 734 amino acids (GenBank accession No. EF583058). The homology rates of amino acid sequences of Dd-ace-2 gene between Ditylenchus destructor and Meloidogyne incognita, Caenorhabditis elegans, Dictyocaulus viviparous were 48.0%, 42.7%, 42.1% respectively. The mature acetylcholinesterase sequences of Ditylenchus destructor may encode by the first 701 residues of deduced 734 amino acids.The conserved motifs involved in the catalytic triad, the choline binding site and 10 aromatic residues lining the catalytic gorge were present in the Dd-ace-2 deduced protein. Phylogenetic analysis based on AChEs of other nematodes and species showed that the deduced AChE formed the same cluster with ACE-2s.

Abstract:GABARAP, a microtuble-associated protein, is identified to interact with GABAA receptor. Anchoring of the GABAA receptor to GABARAP helps to cluster the receptor at the synaptic termini and to mediate fast synaptic transmission. GABARAP may mediate interaction of gephyrin with the GABAA receptor to stabilize clusters by forming multimeric structures. Furthermore, GABARAP and gephyrin may play more of a role in receptor sorting and transport to the cell surface than in anchoring to the cytoplasm, because at inhibitory synapses GABARAP appears to associate with transport vesicles rather than the cell surface. The association of GABARAP with NSF (N-ethylmaleimide sensitive factor), a protein involved in intracellular vesicle transport, supports this hypothesis. We cloned cDNA encoding full-length human GABARAP by nested PCR and inserted it into eukaryon expression vector pcDNA6HA and GST fusion protein expression vector pGEX4T2. The recombinant plasmid pGEX4T2-hGABARAP was transformed into E. coli BL21, from which GST-hGABARAP fusion protein was purified after IPTG induction by affinity chromatography with glutathione Sepharose-4B column. The antiserum against GABARAP was generated by immunizing rabbits with the purified GST-hGABARAP and was purified with GST-hGABARAP coupled NHS-activated Sepherose 4 column. The purified polyclonal antibody was effective for Western blotting and immunostaining. The hGABARAP was located both in the cytoplasm and nucleus with an abundant distribution around the peripheral nucleus.

Abstract:We cloned human U6 promoter from pAVU6 + 27 vector into pXSN to transcripe small RNA. Meanwhile, a shRNA targeting GDF-8 was cloned down-stream of the hU6 promoter to construct recombinant vector. Then the packing cell GP-293 was co-transfected the recombinant with pVSV-G to gernarate virus particle. Resistant C2C12 cell pools were screened using G418. Levels of mRNA and protein of GDF-8 were tested by Real-Time PCR and western blotting. Cell proliferation and cell cycle were analyzed using MTT and FACS. The expression of GDF-8 was dramatically decreased by the retrovirus-based system in C2C12 cells. Cells proliferated effectively after integrating the recombinant. The cells in G0/G1 phase decreased by 13.7%, while cells in S phase increased by 14.9%. In conclusion, the retrovirus-based RNAi could be used to stably silence GDF-8. It can be a powerful tool in curing muscle atrophy.

Abstract:Lentiviral vectors were powerful gene delivery tools for gene therapy. We developed a new lentiviral vector pBobi-MIL that constitutively expressed O6-methylguanine-DNAmethyltransferase (MGMT) and Luciferase, linked by the internal ribosomal entry site (IRES), to realize drug tolerance and real time monitoring in vivo. All results from RT-PCR, drug treating clones forming, immunofluorometric assay and chemiluminescence detection showed that cells infected by recombinant lentivirus L-MIL simultaneously expressed these two genes. This lays the foundation for the further research in gene therapy and can also help identify lentivirus titer.

Abstract:In order to obtain salt-tolerant variant plants of Dandelion (Taraxacum officinale Weber), the leaf discs were excised from 20 to 30-day old seedlings to produce callus, then the induced calli were transferred to selection mediums containing 1.5% NaCl. After regenerating and rooting, these salt-tolerant calli finally developed into 12 variant plantlets. Compared with the wild-type, these regenerated plants produced more trichomes on their leaves, and had larger leaves and shorter petioles. Additionally, the dumpy roots and an approximately 2-cm bract in middle parts of the floricanes were clearly observed in these salt-tolerant plants. By RAPD( Random Amplified Polymorphic DNA) and SDS-PAGE analysis, these salt-tolerant plants showed differences from the control at DNA and protein levels. With 1.5% NaCl treatment, the antioxidant enzyme activity, proline content, and flavonoid concentration were higher in these salt-tolerant plants, whereas maloaldehyde concentration was significantly lower. Salt-tolerant lines of T. officinale showed stronger anti-oxidative activity and higher flavonoid contents.

Abstract:Collagen/bone morphogenetic protein composites were prepared with collagen type I sponge and bone morphogenetic protein-2 (BMP-2). The composites were implanted into Latissimus dorsi muscles pouches of rabbits. Samples were studied with ALP staining, Von Kossa staining, HE staining, toluidine blue staining and CD31 histochemical labeling of microvessel. Bony samples were then used to repair mandibular defect. The effects were evaluated by X-ray, compressive strength, economycin fluorescence labeling, HE staining, toluidine blue staining and bone quantity analysis. Bone formation induced by collagen/BMP composites was found as woven bone between 4 and 6 weeks; cartilaginous osteogenesis was the main type of bone formation; microvessels could be seen in the bony tissues; and the bone defects were healed completely 6 weeks after operation. Bone formation induced by collagen/BMP composites in the muscles can be used as a donor to repair the bone defect.

Abstract:Major histocompatibility complex (MHC) tetramer technology offers a powerful means to study specific T cell populations of interest. To investigate the immune response of H-2Db-restricted CD8+ T cells in immunotherapy, we prepared the H-2Db tetramer and verified its effectiveness in enumerating the CD8+ T cells specific for the lymphocytic choriomeningitis virus (LCMV). First, the cDNA encoding H-2Db heavy chain was cloned by RT-PCR from the spleen of a C57BL/6 mouse. The expression vector for H-2Db-BSP, i.e. the ectodomain of H-2Db fused to a BirA substrate peptide (BSP), was constructed and overexpressed in E. coli BL21(DE3). Then, the denatured H-2Db-BSP was refolded in the presence of human β2-microglobulin as well as the GP33-41 peptide (KAVYNFATC, KAV)of LCMV. The biotinylated H-2Db/KAV molecules were purified, then bound to streptavidin-PE and tetramerized. Finally, the prepared H-2Db KAV tetramer reagent was verified by detecting the CD8+ T cells specific for HCMV in KAV peptide vaccinated C57BL/6 mouse, with a mouse receiving subcutaneous injection of only adjuvant as negative control. The results showed that the tetramer positive rates were 0.27%, 0.11%, and 0.24% within the CD8+ T cell populations in the peripheral blood, draining lymph nodes, and spleen of vaccinated mouse, respectively. There was only very low background staining (≤0.01%) of those samples from the control mouse. Beside, the best results were achieved in the staining of the peripheral blood sample. In conclusion, the established procedure of preparing H-2Db tetramer will facilitate the study of the immune responses of antigen-specific CD8+ T cells in the experimental immunotherapy on the mice with H-2Db allele background.

Abstract:Three model silkworms, highly resistant strain, highly susceptible strain and their near isogenic line were established by hybridization and backcross. The resistance of silkworm (Bombyx mori L.) to BmNPV was studied at proteomic level using two-dimensional gel electrophoresis and MALDI TOF/TOF MS. Differential expression profiles of proteome in resistant strain, susceptible strain and near isogenic line were obtained, and 180, 190 and 187 of protein spots were shown, respectively. Among them, 80% were concentrated in pI 5~9. Twelve differential protein spots in total were obtained from 3 gels. Using MALDI TOF/TOF MS, five proteins, including aminoacylase, were identified from these spots. The exclusive expression of aminoacylase in highly resistant strain and near isogenic line and its absence in susceptible strain suggest that it might be a BmNPV-resistance related protein.

Abstract:DNA fragment containing human alpha-defensin 5 mature peptide (mHD-5) coding sequence with biased codons of E. coli was amplified by PCR, which was subsequently cloned into the plasmid pMAL-p2x in order to create pMAL-p2x-mHD-5 expression vector. The plasmid pMAL-p2x-mHD-5 was transferred into engineered strain BL21(DE3) to express heterogeneous fusion protein (MBP-mHD-5). The soluble MBP-mHD-5 targeted protein inducible expressed by IPTG was accounted for about 30% under optimized conditions. The recombinant mHD-5 (rmHD-5) peptide was successfully purified through a separation process including affinity chromatography, Factor Xa digestion and ion exchange chromatography. The bioactivity of rmHD-5 was examined by bacteria-inhibition tests in liquid culture. The growth of E. coli ATCC25922 was dramatically suppressed with an inhibition rate of 90%, with the presence of 62.5mg/mL rmHD-5 in the media. These results indicate that the strategy of soluble expression of fusion protein in E. coli can be a useful and practical way to produce bioactive defensins.

Abstract:Integrin aⅡbb3 of the platelet surfaces regulates the thrombosis formation. aⅡbb3 binds to the RGD sequence (Arg-Gly-Asp) of fibrinogen, promotes the platelet aggregation and finally leads to the thrombus. We obtained the three-dimensional molecular structure of aⅡbb3 using homology-modeling (modeller8v2 software), with integrin avb3 (pdb code 1JV2) as the template. Accordingly, a cyclic RGD(RGD-c) peptide was designed to bind aⅡbb3 as an antagonist and to block the formation of thrombus. We added two amino acids X, Y to both sides of RGD-c. X and Y could bind to each other by disulfide bond that finally made RGD-c a cyclic peptide. The optimum structure of RGD-c was obtained from the energetic optimization processes. All amino acids were placed at the X and Y to conduct Molecular Docking to the integrin aⅡbb3. We got the optimum structure of RGD-c by energetic optimization and the antagonistic combination analysis. The results might provide an insight into designing and screening integrin aⅡbb3 antagonists.

Abstract:We used amino acid composition distribution (AACD) to discriminate thermophilic and psychrophilic proteins. We used 10-fold cross-validation and independent testing with other dataset to evaluate the models. The results showed that when the segment was 1, the overall accuracy reached 92.9% and 90.2%, respectively. The AACD method improved the prediction accuracy when support vector machine was used as the classifier. When six new features were introduced, the overall accuracy of random forest improved to 93.2% and 92.2%, the areas under the receiver operation characteristic curve were 0.9771 and 0.9696, which was better than other ensemble classifiers and comparable with that of SVM.

Abstract:Ethanol tolerance of self-flocculating yeast SPSC01 was studied in a 3-L bioreactor under fed-batch culture. Yeast floc populations with the average sizes around 100, 200, 300, and 400 μm were obtained by adjusting the mechanical stirring rates of the fermentation system. When subjected to 20% (V/V) ethanol shock for 6 h at 30°C, the remained cell viability was 3.5%、26.7%、48.8% and 37.6% for the aforementioned four floc populations, respectively. The highest ethanol yield 85.5% was achieved for the 300 μm flocs, 7.2% higher than that of the 100 μm flocs. The amounts of trehalose and ergosterol (including free ergosterol and total ergosterol) were positively correlated with the average size distributions from 100 to 300 μm. However, in the 400 μm flocs, the content of trehalose and ergosterol decreased, which coincided with its reduced ethanol tolerance compared to that of the 300 μm flocs. Furthermore, when subjected to 15% (V/V) ethanol shock at 30°C, the equilibrium nucleotide concentration and plasma membrane permeability coefficient(P′) of the 300 μm flocs accounted for only 43% and 52% respectively of those of the 100 μm and 200 μm populations. The effect of floc size distribution on the ethanol tolerance of the self-flocculating yeast strain SPSC01 was closely related to plasma membrane permeability. An optimal floc size distribution with the highest ethanol tolerance and ethanol production level could be obtained by controlling mechanical stirring speed of the bioreactor, which provides basis for the process optimization of fuel ethanol production using this self-flocculating strain.

Abstract:Use of genetically engineered microorganisms (GEMs) for pollution abatement has been limited because of the risks associated with their uncontrolled release in environment. In this study, a pollutant-dependent bacterial containment system was constructed in E. coli JM109. The system consisted of two plasmids containing a killing element and a regulatory element respectively. The survival of strains can be regulated by the concentration of salicylate in environment. In the presence of salicylate, the expression of the suicide gene gef was inhibited with the synthesis of LacI protein, leading to the normal proliferation of the strain. While in the absence of salicylate, the expression of the regulatory element was cancelled, and the expression of the suicide gene gef led to a high rate of cell killing. This containment system can be used as a model during the construction of genetically engineered strains for bioremediation.

Abstract:A fusion gene called Ig-BDNF, in which brain-derived neurotrophic factor cDNA fused to the 3’ end of signal peptide of Ig coding sequence, was constructed by PCR, digested and subcloned into shuttle plasmid pSNAV to obtain a recombinant plasmid pSNAV-Ig-BDNF. Then the plasmid encoding fusion protein was transfected into 293 cell lines and the stably transfected clones were selected with neomycin. AAV1 containing Ig-BDNF fusion gene vectors were obtained by super-infection by Herpes virus. The resultant adeno-associated virus vectors AAV-Ig-BDNF were confirmed by PCR, Western blotting and a sandwich enzyme-linked immunosorbent assay (ELISA) after infection of 293 cell lines. The results indicated that AAV-Ig-BDNF contained the target gene, and infected cells and produced the fusion protein into the supernatant. The content of BDNF in medium per 5×104 cells over a 24 h incubation period reached 1000 pg/mL. With the help of non-replicative adenovirus during AAV-Ig-BDNF infection, the expression of BDNF increased 7~8 fold, and the enhancement of BDNF gene expression was observed in a concentration-dependent manner. These results suggested that a functional AAV-Ig-BDNF was successfully constructed and it offers basis for further study for gene therapy of neural degeneration diseases.

Abstract:We studied the influence of the first intron and 3′-regulatory region of ovalbumin gene (ov) on oviduct-specific transgene expression. The 3′-regulatory region in the oviduct-specific expression vector containing human tissue kallikrein (hK1) cDNA was replaced with bovine growth hormone (BGH) poly A, and the first intron was deleted by restriction enzyme digestion, resulting in five new vectors pOV2K, pOV3K, pOV4K, pOV5K and pOV6K. After mixing with polyethylenimine, we injected same copies of the five vectors via wing vein route into laying hens and compared their expression levels by quantitative assay for enzymatic activities in the egg whites. Among the five vectors tested, the pOV2K containing both the 5′- and 3′-regulatory regions expressed highest level of rhK1 activity, followed by pOV3K with the 3′-regulatory region replaced with BGH poly A, and then by the first intron-shortened vectors pOV4K, pOV5K and pOV6K. These data suggest that both the first intron and 3′-regulatory region of ov gene have enhancing effect on transgene expression in oviduct cells, which should be included in oviduct-specific expression vectors.