EgMADS3 directly regulates EgLPAAT to mediate medium-chain fatty acids (MCFA) anabolism in the mesocarp of oil palm.

KEY MESSAGE: EgMADS3, a pivotal transcription factor, positively regulates MCFA accumulation via binding to the EgLPAAT promoter, advancing lipid content in mesocarp of oil palm. Lipids function as the structural components of cell membranes, which serve as permeable barriers to the external environment of cells. The medium-chain fatty acid in the stored lipids of plants is an important renewable energy. Most research on MCFA production in plant lipid synthesis is based on biochemical methods, and the importance of transcriptional regulation in MCFA synthesis and its incorporation into TAGs needs further research. Oil palm is the most productive oil crop in the world and has the highest productivity among the main oil crops. In this study, the MADS transcription factor (EgMADS3) in the mesocarp of oil palm was characterized. Through the VIGS-virus induced gene silencing, it was determined that the potential target gene of EgMADS3 was related to the biosynthesis of medium-chain fatty acid (MCFA). Transient transformation in protoplasts and qRT-PCR analysis showed that EgMADS3 positively regulated the expression of EgLPAAT. The results of the yeast one-hybrid assays and EMSA indicated the interaction between EgMADS3 and EgLPAAT promoter. Through genetic transformation and fatty acid analysis, it is concluded that EgMADS3 directly regulates the mid-chain fatty acid synthesis pathway of the potential target gene EgLPAAT, thus promotes the accumulation of MCFA and improves the total lipid content. This study is innovative in the functional analysis of the MADS family transcription factor in the metabolism of medium-chain fatty acids (MCFA) of oil palm, provides a certain research basis for improving the metabolic pathway of chain fatty acids in oil palm, and improves the synthesis of MCFA in plants. Our results will provide a reference direction for further research on improving the oil quality through biotechnology of oil palm.

Adjuvant DNA vaccine pNMM promotes enhanced specific immunity and anti-tumor effects.

DNA vaccines containing only antigenic components have limited efficacy and may fail to induce effective immune responses. Consequently, adjuvant molecules are often added to enhance immunogenicity. In this study, we generated a tumor vaccine using a plasmid encoding NMM (NY-ESO-1/MAGE-A3/MUC1) target antigens and immune-associated molecules. The products of the vaccine were analyzed in 293 T cells by western blotting, flow cytometry, and meso-scale discovery electrochemiluminescence. To assess the immunogenicity obtained, C57BL/6 mice were immunized using the DNA vaccine. The results revealed that following immunization, this DNA vaccine induced cellular immune responses in C57BL/6 mice, as evaluated by the release of IFN-γ, and we also detected increases in the percentages of nonspecific lymphocytes, as well as those of antigen-specific T cells. Furthermore, immunization with the pNMM vaccine was found to significantly inhibit tumor growth and prolonged the survival of mice with B16-NMM+-tumors. Our data revealed that pNMM DNA vaccines not only confer enhanced immunity against tumors but also provide a potentially novel approach for vaccine design. Moreover, our findings provide a basis for further studies on vaccine pharmacodynamics and pharmacology, and lay a solid foundation for clinical application.

Association of H3K9me3 with breast cancer prognosis by estrogen receptor status.

BACKGROUND: Cellular experiments revealed that a decreased histone H3 lysine 9 trimethylation (H3K9me3) level was associated with the upregulation of oncogenes in breast cancer cells. Moreover, the role of H3K9me3 in breast cancer was closely associated with estrogen receptor (ER) status. Therefore, we aimed to examine the prognostic value of H3K9me3 on breast cancer by ER status. The level of H3K9me3 in tumors were evaluated with tissue microarrays by immunohistochemistry for 917 women diagnosed with primary invasive breast cancer. Hazard ratios (HRs) and their 95% confidence intervals (CIs) for overall survival (OS) and progression-free survival (PFS) were estimated using Cox regression models. Interaction between H3K9me3 and ER on the prognosis was assessed on multiplicative scale. RESULTS: The level of H3K9me3 in tumor tissues was lower than that in adjacent tissues. The high level of H3K9me3 was associated with a better OS (HR = 0.43, 95% CI: 0.21-0.86) and PFS (HR = 0.49, 95% CI: 0.29-0.81) among only ER-positive but not ER-negative tumors. Moreover, the interaction between the level of H3K9me3 and ER status (negative and positive) on the prognosis was significant (Pinteraction = 0.011 for OS; Pinteraction = 0.022 for PFS). Furthermore, the ER-positive tumors were stratified by ER-low and ER-high positive tumors, and the prognostic role of H3K9me3 was significant among only ER-high positive patients (HR = 0.34, 95% CI: 0.13-0.85 for OS; HR = 0.47, 95% CI: 0.26-0.86 for PFS). CONCLUSIONS: Our study showed that the prognostic value of H3K9me3 on breast cancer was related to ER status and expression level, and the high level of H3K9me3 was associated with a better prognosis among ER-positive tumors, particularly ER-high positive tumors.

MiR-501-5p alleviates cardiac dysfunction in septic patients through targeting NR4A3 to prevent its binding with Bcl-2.

Sepsis-induced myocardial dysfunction is a common complication in septic patients. To date, a limited number of biomarkers that could predict cardiomyocyte apoptosis have been explored. In this study, we successfully established a cecal ligation and puncture (CLP)-induced septic model, and it was found that miR-501-5p expression was down-regulated in peripheral blood samples of septic patients with cardiac dysfunction, lipopolysaccharide (LPS)-induced cardiomyocytes, and the myocardium and peripheral blood in the septic model. Moreover, it was revealed that miR-501-5p overexpression could increase left ventricular diastolic pressure (LVDP), fractional shortening (FS), ejection fraction (EF), and maximum rate of the rise of left ventricular pressure (+dp/dt) in vivo, while it decreased the levels of myocardial injury-related indicators. In addition, LPS induction accelerated apoptosis and elevated the inflammation in HL-1 and HCM cells, which could be reversed by miR-501-5p overexpression. Mechanistically, we considered nuclear receptor subfamily 4 group A member 3 (NR4A3) as the target of miR-501-5p, and it was found that miR-501-5p prevented the binding between NR4A3 and Bcl-2. It was found that miR-501-5p exerted an inhibitory effect on cardiomyocyte apoptosis and inflammation in a NR4A3-dependent manner. Overall, our results may provide evidence for consideration of miR-501-5p in the therapy of sepsis.

Minocycline promotes cardiomyocyte mitochondrial autophagy and cardiomyocyte autophagy to prevent sepsis-induced cardiac dysfunction by Akt/mTOR signaling.

Myocardial damage is responsible for the high mortality of sepsis. However, the underlying mechanism is not well understood. Cardiomyocyte autophagy alleviates the cardiac injury caused by myocardial infarction. Enhanced cardiomyocyte autophagy also has protective effects against cardiomyocyte mitochondrial injury. Minocycline enhances autophagy in many types of cells under different types of pathological stress and can be easily taken up by cardiomyocytes. The present study investigated whether minocycline prevented myocardial injury caused by sepsis and whether cardiomyocyte autophagy participated in this process. The results indicated that minocycline enhanced cardiomyocyte mitochondrial autophagy and cardiomyocyte autophagy and improved myocardial mitochondrial and cardiac function. Minocycline upregulated protein kinase B (Akt) phosphorylation, inhibited mTORC1 expression and enhanced mTORC2 expression. In conclusion, minocycline enhanced cardiomyocyte mitochondrial autophagy and cardiomyocyte autophagy and improved cardiac function. The underlying mechanisms were associated with mTORC1 inhibition and mTORC2 activation. Thus, our findings suggest that minocycline may represent a potential approach for treating myocardial injury and provide novel insights into the underlying mechanisms of myocardial injury and dysfunction after sepsis.

[Expression and activity identification of a fusion protein for promoting adenovirus infection efficiency of dendritic cells].

OBJECTIVE: To construct a prokaryotic expression plasmid for CT40L, express the target protein in E. coli, purity the CT40L fusion protein and verify its antigenicity. METHODS: Gene sequences of Coxsackie and adenovirus receptor (CAR), bacteriophage T4 fibritin and mouse CD40L were found out in GenBank. Then functional domains of three molecules were linked to form a fusion sequence which was then optimized for prokaryotic expression. The optimized sequence was cloned into prokaryotic expression vector pET42a(+) to construct the recombinant expression vector pET42a-CT40L. The recombinant vector was transformed into BL21 (DE3) and the fusion protein CT40L/GST was induced by IPTG. The fusion protein was then subjected to purification using GST affinity chromatography and to identification of the immune activity using Western blotting and ELISA. RESULTS: The recombinant expression vector was verified correct by double digestion with Nco I and EcoR I. After IPTG induction, SDS-PAGE showed that the relative molecular mass of the fusion protein was about 78 kDa and that the purity of the purified protein reached 90%. Western blotting and ELISA demonstrated that the purified fusion protein had a valid antigenicity. CONCLUSION: The prokaryotic expression plasmid pET42a-Ct40L was successfully constructed and expressed in E. coli, and the purified fusion protein was proved to have a good antigenicity.

Enhancement of antitumor immunity using a DNA-based replicon vaccine derived from Semliki Forest virus.

A DNA-based replicon vaccine derived from Semliki Forest virus, PSVK-shFcG-GM/B7.1 (Fig. 1a) was designed for tumor immunotherapy as previously constructed. The expression of the fusion tumor antigen (survivin and hCGß-CTP37) and adjuvant molecular protein (Granulocyte-Macrophage Colony-Stimulating Factor/ GM-CSF/B7.1) genes was confirmed by Immunofluorescence assay in vitro, and immunohistochemistry assay in vivo. In this paper, the immunological effect of this vaccine was determined using immunological assays as well as animal models. The results showed that this DNA vaccine induced both humoral and cellular immune responses in C57BL/6 mice after immunization, as evaluated by the ratio of CD4+/CD8+ cells and the release of IFN-γ. Furthermore, the vaccination of C57BL/6 mice with PSVK-shFcG-GM/B7.1 significantly delayed the in vivo growth of tumors in animal models (survivin+ and hCGß+ murine melanoma, B16) when compared to vaccination with the empty vector or the other control constructs (Fig. 1b). These data indicate that this type of replicative DNA vaccine could be developed as a promising approach for tumor immunotherapy. Meanwhile, these results provide a basis for further study in vaccine pharmacodynamics and pharmacology, and lay a solid foundation for clinical application.

[Influence of electroporation on immunogenicity of the DNA vaccine pVAX-tG250FcGB].

OBJECTIVE: To investigate the influence of electroporation on the immunogenicity of the DNA vaccine pVAX- tG250FcGB. METHODS: The DNA vaccine pVAX-tG250FcGB was constructed by inserting the coding gene of tG250 fusion genes into the expression vector pVAX. The DNA vaccine was delivered in BALB/c mouse by electroporation or intramuscular injection, and the induced antigen specific immune responses were compared. RESULTS: The vaccine delivered by electroporation and intramuscular injection both induced immune responses in BALB/c mouse, but electroporation produced an obviously stronger effect than intramuscular injection. CONCLUSION: Electroporation-mediated DNA vaccine delivery can produce strong immune response in mice and is an effective means for studying the immunogenic effect of DNA vaccine pVAX-tG250FcGB.

[Cloning, prokaryotic expression, and antigenicity identification of extracellular domain of mouse CD40].

OBJECTIVE: To construct a prokaryotic expression plasmid for extracellular domain of mouse CD40 (mCD40), express the mCD40/GST recombinant protein in E.coli, purify the mCD40/GST recombinant protein and characterize its antigenicity. METHODS: Extracellular domain of mouse CD40 was amplified by PCR from cell line DC2.4 and then was cloned into prokaryotic expression vector pGEX-6P-1 to construct the recombinant expression vector pGEX-6P-1-mCD40. The expression vector was transformed into E.coli BL21 (DE3) and the fusion protein mCD40/GST was induced by IPTG. The fusion protein was purified through sepharose 4B. Then antigenicity of the purified mCD40/GST protein was verified by Western blotting and ELISA. RESULTS: The PCR product was verified by DNA sequencing to be consistent with the sequence of mouse CD40 on GenBank. The recombinant plasmid was identified by double digestion successfully. SDS-PAGE analysis showed the relative molecular mass of the fusion protein induced by IPTG was 45 000. Western blotting and ELISA demonstrated that the purified mCD40/GST protein had a good antigenicity. CONCLUSION: The prokaryotic expression plasmid pGEX-6P-1-mCD40 was constructed successfully. In E.coli BL21 (DE3) transformed with the plasmid, the mCD40/GST fusion protein was expressed by IPTG induction. The purified mCD40/GST fusion protein had a high antigenicity, which provides a strong support for the future study of CD40.

[Construction and identification of a recombinant replication-defective adenovirus vector encoding p53AIP1 and its expression in human HeLa cells].

OBJECTIVE: To construct a recombinant replication-defective adenovirus vector carrying p53AIP1 (p53-regulated apoptosis-inducing protein 1) gene and observe its expression in human HeLa cells. METHODS: Specific primers were designed according to p53AIP1 gene sequence and inserted specific enzyme cutting sites. P53AIP1 gene was amplified by PCR and cloned into the adenovirus shuttle plasmid pDC316 to construct the recombinant vector pDC316-p53AIP1, which was co-transfected with helper plasmid pBHGloxδE1, 3Cre into HEK293 cells by Lipofectamine(TM); 2000. The recombinant replication-defective adenovirus (Ad-p53AIP1) was generated by means of homologous recombination of the two plasmids in HEK293 cells with the Cre-loxP recombinase system and harvested after 12 days. Ad-p53AIP1 and Ad-null were respectively transfected into HeLa cells at MOI=100. Then the expression of p53AIP1 gene was detected by Western blotting. RESULTS: pDC316-p53AIP1 was constructed successfully. The new constructed vector was confirmed by PCR analysis, double enzyme digestion and DNA sequencing. The results were in conformity with the expected. Western blotting demonstrated that the target p53AIP1 proteins were effectively expressed in the transfected HeLa cells. CONCLUSION: The recombinant adenovirus vector of Ad-p53AIP1 was successfully established, and it was proved to have a strong ability of infectivity.

[Prokaryotic expression, purification and antigenicity identification of human renal cell carcinoma-associated antigen G250].

OBJECTIVE: To amplify human renal cell carcinoma (RCC)-associated antigen G250 gene and construct a recombinant plasmid pET-42a-hG250, express and purify human G250 protein and identify its antigenicity. METHODS: The gene of human G250 was amplified from pGEM-T-G250 by PCR. After sequencing, the PCR product (112-1242 bp) was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-hG250. The plasmid was transformed into BL21 (DE3) and human G250 protein was expressed under the induction of IPTG. The fusion protein was purified and identified by SDS-PAGE, Western blotting and ELISA sequentially. RESULTS: The human G250 prokaryotic expression vector pET-42a-hG250 was successfully constructed as confirmed by enzyme digestion and DNA sequencing. After transformation into BL21 (DE3), the target protein was successfully induced to express and purified as expected. Western blotting and ELISA demonstrated that the purified human G250 protein had a desirable immunogenicity. CONCLUSION: The recombinant prokaryotic expression vector pET-42a-hG250 has been constructed successfully. The purified human G250 protein has a good antigenicity.

[The expression, purification and characterization of ß-hCG protein in E.coli].

OBJECTIVE: To obtain ß-chain human chorionic gonadotropin (ß-hCG) fusion protein (ß-hCG/GST) and identify its antigenicity. METHODS: The full-length gene of ß-hCG was amplified by PCR. The PCR product was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-ß-hCG, and then it was transformed into BL21 (DE3) for ß-hCG/GST fusion protein expression under IPTG induction. After SDS-PAGE assay, the fusion protein was purified by affinity chromatography and identified by Western blotting. The antigenicity of the purified fusion protein was characterized by ELISA. RESULTS: The ß-hCG gene we obtained had an identical sequence to that retrieved in GenBank. The prokaryotic expression vector pET-42a-ß-hCG was successfully constructed as confirmed by enzyme digestion and DNA sequencing. Both Western blotting and ELISA demonstrated that the purified ß-hCG fusion protein had satisfactory antigenicity. CONCLUSION: The purified ß-hCG/GST fusion protein with satisfactory antigenicity has been obtained, which will facilitate further study on active anti-tumor immunotherapy targeting ß-hCG.

Design, expression and characterization of a novel coexpression system of two antiarthritic molecules.

The complexity of rheumatoid arthritis (RA) pathogenesis makes combined blockade of multiple targets an attractive therapeutic strategy. The combination therapy with anti-TNF plus anti-T-cell has been mostly reported to provide greater efficacy than anti-TNF alone. TNFR (p75)-Fc fusion protein, which has been proven effective in clinics, is chosen as the TNF antagonist in this study. CTLA4-FasL fusion molecule, which has been well characterized in our previous studies for its suppressive effect in rat arthritis model, is chosen as the T-cell antagonist. In this study, furin cleavage site and 2A self-processing sequence were introduced to link upstream TNFR-Fc and downstream CTLA4-FasL and mediate separate coexpression of the two fusion proteins in a single recombinant adeno-associated virus (rAAV) vector. Using this expression system, we generated two fusion proteins with same size as their individual counterparts in vitro and in vivo, and the proteins desirably retained their parent biological activities. In vivo results demonstrated that furin-2A technology is able to regulate separate coexpression of these proteins under arthritic inflammatory conditions. This study describes a single rAAV vector for production of two antiarthritic molecules antagonizing both TNF and T cells, which may serve as an attractive expression system for RA gene therapy.

[Establishment of a pulmonary metastasis model of melanoma with stably expressed hTERT/Luc].

OBJECTIVE: To construct the eukaryotic expression vectors of human telomerase reverse transcriptase (hTERT) and luciferase (Luc) gene, and stably transfect B16 cell line with them, and inoculate mice via caudal vein to construct pulmonary metastasis models. METHODS: The hTERT and Luc cDNA fragments were inserted into eukaryotic expression vectors to obtain the recombinant plasmids pIRES-neo-hTERT and pIRES-hyg3-Luc. The plasmids were then transfected into B16 cells by Lipofectamine(TM); 2000. Afte the stably transfected cell line was screened by G418 and hygromycin B, the transcription and expression of the hTERT and Luc genes were identified by Western blotting and immunofluorescence staining. The stably transfected cells were inoculated via caudal vein into male C56BL/6 mice to construct pulmonary metastasis models. An in vivo imaging system was used to monitor the growth and metastasis of the tumors. RESULTS: A stably transfected cell line was established and the express rates of hTERT and Luc gene in the stable cell line were 84% and 98%, respectively. Pulmonary metastasis models were successfully established and the conditions of the lung metastasis could be detected easily using in vivo imaging system. CONCLUSION: The pulmonary metastasis models with stably expressed hTERT for in vivo imaging system in mice has been successfully established.

[Prokaryotic expression, purification and antigenicity identification of mouse VEGFR2 extracellular 1-4 IgG-like domains].

OBJECTIVE: To obtain 1-4 IgG-like domains of mouse vascular endothelial growth factor receptor 2 (VEGFR2) fusion protein (mVEGFR2D1-4/GST) and identify its antiginicity and biological activity. METHODS: The gene of mVEGFR2D1-4 was amplified by RT-PCR from 14-days embryos of Balb/c mice. The PCR product was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-mVEGFR2D1-4, which was transformed into E. coli BL21 (DE3) strain for mVEGFR2D1-4/GST expression. The fusion protein was identified by SDS-PAGE and Western blotting, and the antigenicity of the protein purified by affinity chromatography was characterized by ELISA. The VEGF blocking effect of the purified protein in human umbilical vein endothelial cells (HUVECs) were evaluated in in vitro cell cultures. RESULTS: The mVEGFR2D1-4 gene was obtained, which had an identical sequence to that retrieved in GenBank. The prokaryotic expression vector for mVEGFR2D1-4 was successfully constructed as confirmed by enzyme digestion and DNA sequencing. Both Western blotting and ELISA demonstrated the antigenicity of the purified mVEGFR2D1-4 fusion protein, which obviously blocked the effect of VEGF in promoting HUVEC proliferation in vitro. CONCLUSION: The mVEGFR2D1-4/GST fusion protein obtained shows a strong antigenicity and biological activity to facilitate further study of active anti-tumor immunotherapy targeting VEGFR2.

[Construction of an anti-tumor immunogene vaccine pVAX-IL-12-GB and its expression in vivo and in vitro].

OBJECTIVE: To construct a novel immunogene therapeutic plasmid that expresses human interleukin-12 (IL-12), granulocyte-macrophage colony stimulating factor (GM-CSF) and B7.1 and observe its expression in vivo and in vitro. METHODS: Human IL-12 gene fragment was cloned into the upper stream of IRES gene in the previously constructed plasmid pVAX-IRES-GM-CSF-B7.1, and the positive recombinant plasmid pVAX-IL-12-GB was transfected into 293T cells via Lipofectamine 2000. The expressions of IL-12 and GM-CSF-B7.1 mRNA and proteins in the transfected cells were assayed by RT-PCR and ELISA, and B7.1 expression was tested by fluorescence-activated cell sorting and immunofluorescence assay. The plasmid pVAX-IL-12-GB was delivered into mouse muscle by electroporation, and the expression of IL-12 in the muscle tissue was identified by immunohistochemistry. RESULTS: Enzyme digestion, PCR and sequence analysis all confirmed successful construction of the recombinant plasmid pVAX-IL-12-GB. IL-12, GM-CSF and B7.1 expressions were all detected in transfected 293T cells, and the expression of IL-12 was also detected in the transfected mouse muscular tissues. CONCLUSION: A novel anti-tumor immunogene vaccine constructed can be expressed both in vivo and in vitro, which facilitates further studies of tumor immunogene therapy.

[Prokaryotic expression, purification and antigenicity identification of mouse prostate stem cell antigen].

OBJECTIVE: To amplify mouse prostate stem cell antigen (mPSCA) gene and construct a recombinant plasmid to obtain mPSCA protein and identify its antigenicity. METHODS: The gene of mPSCA was amplified by RT-PCR from mouse prostate cancer cell line RM-1 with the signal peptide sequence removed. The PCR product was cloned into pET-42a prokaryotic expression vector to construct the recombinant plasmid pET-42a-mPSCA, which was transformed into BL21 (DE3) for mPSCA expression. The fusion protein was purified and identified by SDS-PAGE and Western blotting. The antigenicity of the purified protein was characterized by ELISA. RESULTS: The mPSCA gene was obtained with an identical sequence to that retrieved in GenBank. The prokaryotic expression vector for mPSCA was successfully constructed as confirmed by enzyme digestion and DNA sequencing. Both Western blotting and ELISA demonstrated the antigenicity of the purified mPSCA protein. CONCLUSION: The purified mPSCA obtained possesses good antigenicity, which will facilitate further study of immunotherapy for prostate cancer targeting PSCA.

S-Nitrosylation of mitogen activated protein kinase phosphatase-1 suppresses radiation-induced apoptosis.

Radiotherapy is a key modality for head and neck cancer (HNC) treatment. Mitogen activated protein kinase phosphatase-1 (MKP-1) protein levels are elevated in various tumors and are negatively correlated with efficacy of chemo- or radio-therapy. However, the mechanisms underlying the moderate radiosensitivity of HNC and the increased MKP-1 protein levels are still dismal. Here we show that S-nitrosylation of MKP-1 on Cysteine 258 enhances MKP-1 protein stability, phosphatase activity, and MKP-1-mediated anti-apoptotic effect on HNC radiotherapy. Co-culturing MKP-1 transfected HNC cell lines with activated macrophages for mimicking the microenvironment of the irradiated cancer cells further confirms that S-nitrosylation-mediated increase of MKP-1 activity correlates with decrease of HNC radiosensitivity. Therefore, S-nitrosylation of MKP-1 presents a novel mechanism underlying the enhanced MKP-1 expression levels and MKP-1-mediated radio-resistance in head and neck cancer.

[Construction of a replicative anti-tumor DNA vaccine PSCK-2PFcGB and its expression in vivo and in vitro].

OBJECTIVE: To construct a replicative anti-tumor DNA vaccine PSCK-2PFcGB based on Semliki Forest Virus (SFV) replicon vector and observe its expression in vivo and in vitro. METHODS: The plasmid pVAX1-2PFcGB was digested with Nhe I, and the digestion product was blunted prior to further digestion with BssH II to obtain the fragment 2PFcGB, a fusion gene containing the multitarget complex antigen 2PAG encoding both the most cytotoxic T lymphocyte epitopes of human survivin and chorionic gonadotropin ß chain-CTP37 of human and monkey. The 2PFcGB fragment was inserted into the PSCK vector digested by Sma I. The products with the expected size were extracted and ligated, and the positive clones were screened by kanamycin and amplified. The recombinant PSCK-2PFcGB, following identification by colony PCR and restriction endonuclease Nde I, was transfected into 293T cells via lipofectamine 2000 and its expression was detected. The recombinant plasmid was also transfected into mouse quadriceps femoris muscle to observe its expression in vivo by immunohistochemistry. RESULTS: Nde I digestion resulted in a fragment of the expected size. Transfection with the recombinant plasmid PSCK-2PFcGB resulted in successful expression of the antigen and adjuvant molecular protein in 293T cells, with the positivity rates of 5.70% and 19.75%, respectively. The fusion tumor antigen survivin and hCGß-CTP37 were also detected in the muscular tissues of the mice. CONCLUSION: A novel replicative anti-tumor DNA vaccine PSCK-2PFcGB has been successfully constructed and can be expressed in 293T cells and in the muscular tissues of immunized mice, which provide a basis for further studies of the antitumor activity and immunological mechanism of the DNA vaccine.

[Construction of eukaryotic expression vector of human hCGbeta and establishment of stably transfected B16 cell line].

AIM: To construct the eukaryotic expression vector of human hCGbeta and stably transfect B16 cell line with it. METHODS: The full length of hCGbeta cDNA fragment was amplified by PCR and inserted into eukaryotic expression vector pIRES-neo, added the restriction enzyme position and 6xHis tag. After identification of restriction digestion and PCR, The recombinant plasmid pIRES-neo-hCGbeta-(His)6; was obtained. Then transfected it into B16 cells by lipofectamine 2000. After screening culture by G418, a stably transfected cell line was established, the transcription and expression of the hCGbeta gene was identified by RT-PCR, Western blot and immunofluorescence assay. RESULTS: The eukaryotic expression vector pIRES-neo-hCGbeta-(His)6; was successfully constructed. A stably transfected cell line was established and the expression rate of hCGbeta gene was higher than 90%. CONCLUSION: The established cell line can highly express hCGbeta stably, the expression of the target gene provide a solid experimental foundation for further studies on the function of the hCGbeta, and which will contribute to the research of hCGbeta gene in the tumor immunotherapy.