Recombinant human zona pellucida proteins ZP1, ZP2 and ZP3 co-expressed in a human cell line

Aim: To produce biologically active recombinant human (rh) ZP proteins in a human cell for use in sperm function tests. Methods: The human embryonic kidney cell line 293T was employed to produce rhZP1, rhZP2 and rhZP3 proteins individually and together by co-expression. Presence of these proteins in the culture medium and cell lysate was assessed by Western blotting analysis. The effect of the recombinant proteins on the human AR was assessed. Results: RhZP2 and rhZP3 were secreted into the culture medium, whereas rhZPl was found only in the cell lysate. Interestingly, when all zona pellucida proteins were co-expressed in the same cells, rhZPl was also secreted into the culture medium. However, despite the presence of all three ZP proteins in sufficient concentration and evidence of heavy glycosylation on gel electrophoresis, biological activity to induce the AR was not observed. Conclusion: RhZP1, rhZP2 and rhZP3 were successfully expressed in the human embryonic kidney cell line 293T. It appears that an interaction amongst these proteins may be required for release of rhZPl from the cell. Although this approach is not satisfactory for producing active human ZP proteins, it makes a significant contribution to the understanding of the structural and functional characteristics of the ZP proteins.

Rat recombinant β-defensin 22 is a heparin-binding protein with antimicrobial activity

Approximately 40-50 β-defensins are predominantly expressed in the male reproductive system of mammals. This selective expression raises the question as to the roles of these molecules in innate immunity and fertility in the male reproductive tract. Rat β-defensin 22 is an epididymis-specific β-defensin expressed in segments 12-14 of the epididymis. This protein contains both β-defensin and lectin signature sequences, yet its antimicrobial activity and carbohydrate-binding ability have not been shown. We herein demonstrated the antimicrobial activity of recombinant rat β-defensin 22 against Escherichia coliand Candida albicans. Its lectinJike activity was also investigated by demonstrating its binding ability with heparin beads. This heparin-binding activity implies some potential roles for this defensin in determining the fertilisation capabilities of sperm.

Expression of fluorescent tagged recombinant erythroferrone protein

Objective: To produce fluorescent tagged recombinant erythroferrone protein(ERFE_eGFP) for laboratory investigations. Methods: Erythroferrone(ERFE) gene was fused to green fluorescent protein(eGFP) gene and cloned in a pSecTag2Hygro plasmid. The constructed plasmid was amplified in Escherichia coli DH5α and the eGFP-fused ERFE(ERFE_eGFP) protein was expressed in human embryonic kidney(HEK293T) cell line. Results: The plasmid constructed from colony C6 contained ERFE_eGFP with the correct restriction sizes of 4.2 kb and expressed secretory ERFE_eGFP fusion protein(approximately size of 75 kDa) in HEK293T cell line. Conclusions: ERFE_eGFP recombinant protein is successfully expressed as a secretory functional protein and could be sensitively detected using fluorometry. This fusion protein might benefit future applications for localization of cellular ERFE receptors and competitive immunoassay of ERFE concentration.

Induction of Chondrogenesis of Adipose-derived Stem Cells by Novel Recombinant TGF-β3 Fusion Protein

Summary： A new type of TGF-β3 fusion protein with targeted therapy function was constructed, and its feasibility and target specificity of inducing chondrogenesis were investigated by transfecting LAP-MMP-mTGF-β3 gene into adipose-derived stem cells （ADSCs）. The recombinant pIRES- EGFP-MMP was constructed by inserting the sense and antisense DNA of encoding the amino acid of the synthetic MMP enzyme cutting site into the eukaryotic expression vector pIRES-EGFE LAP and mTGF-β3 fragments were obtained by using RT-PCR and inserted into the upstream and downstream of MMP from pIRES-EGFP-MMP respectively, and the recombinant plasmid of pIRES-EGFP- LAP-MMP-mTGF-β3 was constructed, which was transferred to ADSCs. The ADSCs were cultured and divided in three groups： experimental group （MMP group）, negative control group （no MMP） and non-transfection group. The morphological changes were observed microscopically, and the expression of proteoglycan and type II collagen （Col II） was detected by using Alcian blue staining and immuno- histochemistry staining at 7th, 14th and 21st day after culture. The recombinant plasmid of pIRES-EGFP-LAP-MMP-mTGF-β3 was correctly constructed by methods of enzyme cutting and se- quencing analysis. The mTGF-β3 fusion protein was successfully expressed after transfection, and in the presence of the MMP, active protein mTGF-β3 was generated, which significantly promoted differ- entiation of ADSCs into chondrocytes and the expression of cartilage matrix. The novel fusion protein LAP-MMP-mTGF-β3 can targetedly induce differentiation of ADSCs into chondrocytes, which would open up prospects for target therapy of cartilage damage repair in future.

Recombinant human bone morphogenetic protein-7 expressed from CHO cells possessing the activity of bone-induced in vitro

Objective To express the recombinant human bone morphogenetic protein-7 (rhBMP-7) in Chinese hamster ovary (CHO) cells and to establish the in vitro biological activity assay of rhBMP-7. Methods Human BMP-7 cDNA was subcloned into pcDNA3.1 mammalian expression vector and transfected to CHO cells by using the lipofectin transfection method. BMP-7 expression cell culture supernatants were harvested and purified for target protein. To analyze the bioactivity of the secreted rhBMP-7, a novel in vitro assay was established by measuring its alkaline phosphatase (ALP) stimulating of osteoblast cell line, W-20-17. Results BMP-7 stably expressing cell clone was selected, which secreted mature disulfide-linked homodimer form of hBMP-7 and had an apparent molecular weight of 36kDa. rhBMP-7 with >95% purity was obtained using 3 step chromatography method. Bioactivity assay showed that the purified protein specifically stimulated W-20-17 cell producing ALP, with a 4-fold increase of ALP activity at 100ng/ml or more, and the EC50 of 15.6ng/ml. Conclusion Purified rhBMP-7 from this CHO expression system has significant biological activity in induction of osteoblast phenotype, which demonstrates potential bone regeneration activity.

Evaluation of Six Recombinant Proteins for Serological Diagnosis of Lyme Borreliosis in China

Objective In this study, we evaluated the diagnostic efficiency of six recombinant proteins for the serodiagnosis of Lyme borreliosis （LB） and screened out the appropriate antigens to support the production of a Chinese clinical ELISA （enzyme-linked immunosorbent assay） kit for LB. Methods Six recombinant antigens, Fla B.g, OspC B.a, OspC B.g, P39 B.g, P83 B.g, and VlsE B.a, were used for ELISA to detect serum antibodies in LB, syphilis, and healthy controls. The ELISA results were used to generate receiver operating characteristic （ROC） curves, and the sensitivity and specificity of each protein was evaluated. All recombinant proteins were evaluated and screened by using logistic regression models. Results Two IgG （VISE and OspC B.g） and two IgM （OspC B.g and OspC B.a） antigens were left by the logistic regression model screened. VIsE had the highest specificity for syphilis samples in the IgG test （87.7%, P〈0.05）. OspC B.g had the highest diagnostic value in the IgM test （AUC=0.871）. Interactive effects between OspC B.a and Fla B.g could reduce the specificity of the ELISA. Conclusion Three recombinant antigens, OspC B.g, OspC B.a, and VisE B.a, were useful for ELISAs of LB. Additionally, the interaction between OspC B.a and Fla B.g should be examined in future research.

Safety of Human Recombinant Proteins

Recombinant human proteins play an important role in therapy, especially in stimulating the hematopoiesis after chemotherapy, e. g., erythropoietin and colony stimulating factors,while several promising candidates such as IL-6, IL-12, thrombopoietin and others are in clinical development. Since the recombinant proteins are copies of endogenous proteins, it was assumed that they would be well tolerated. While this assumption is correct for some, other proteins proved to be less well tolerated. Therefore, preclinical safety assessment of these pro teins is necessary. Based on the experience with several proteins, some guidance for the safety assessment can be given. Furthermore, data are presented demonstrating that preclinical toxi city studies may have a predictive value for man. Limitations of the classical approach of safety tests and new concepts are discussed

Detection of Antibodies against Toxoplasma gondii by ELISA with Recombinant Microneme Protein 3

[Objective] To develop a new method for serodiagnosis of swine toxoplasmosis. [Method] With the purified recombinant microneme protein 3 （rMIC3） as coating antigens, an indirect ELISA was developed for detection of antibodies against Toxoplasma gondii. [ Result] The optimal working concentration of rMIC3 was 3. 40 ug/ml, and the optimal degree of dilution of sera was 1：160. Cross-reaction was not observed between the Toxoplasma gondii-positive sera and the positive sera against classical swine fever virus or some other pathogens. The developed ELISA had 92.56% coincidence rate with latex agglutination test. [ Conclusion] The developed ELISA is sensitive, rapid, specific and reproducible, and thus it can be applied in serodiagnosis and seroprevalence investigation of swine toxoplasmosis.

Active Peptides and Motifs within Collagen and Other ECM Proteins

Collagens are the most abundant proteins in mammals and form an extracellular matrix (ECM) with other components as the structural support of muscle, skin, corneas and blood vessels etc. Other than providing structural support, the ECM exhibits active communication with cells and influences many cellular processes including migration, wound healing, differentiation and cancer metastasis. Though collagen proteins contain highly repetitive primary sequences and defined tertiary structures, more and more studies have shown that many short peptides/motifs within collagen proteins play key roles in various biological processes. These short sequences are effective within triple helical structures or independently as stand-alone molecules resulting from proteolytic degradation. Besides endogenous ECM-derived peptides, many more functional peptides have been produced by tissue processing, chemical synthesis, and recombinant protein production. In this review, we summarize different peptides/motifs identified in collagen and other ECM proteins and discuss their potential for medical, personal care, and cosmetics applications.

Cloning and expression of human arresten gene and effect of its recombinant protein on endothelial cell proliferation

To clone human arresten gene and investigate biological activity of the recombinant protein.Methods Human arresten gene was obtained from the plasmid pGEMArr and subcloned into the BamHⅠ and Pst Ⅰ restriction sites of prokaryotic expression vector pRSET containing T7 promoter.The recombinant plasmid pRSETAN was subsequently transformed into the strain E.coli BL21(DE3),and the target gene was expressed under induction of IPTG.The expressed protein was extracted,purified by Ni 2+ chelation affinity chromatography and refoled.The effect of the recombinant protein on proliferation of human umbilical vein endothelial cells (HUVECs) was also analyzed with the MTT assay.Results Endonuclease digesting and DNA sequencing confirmed that the arresten gene was correctly inserted into the expression vector.The recombinant protein was hightly expressed in the form of inclusion body in the host bacteria after induction.SDS-PAGE analysis revealed that the recombinant protein with a molecular weight of 26×103 amounted to 27% of the total bacterial proteins.The purity of the expected protein could reach over 96% through affinity chromatography.After renaturation,the recombinant protein could reach over 96% through affinity chromatography.After renaturation,the recombinant protein could significantly suppress proliferation of human umbilical vein endothelia cells(HUVECs) induced by vascular endothelial growth factor(VEGF).Conclusion Human arresten gene was successfully cloned into the expression vector pRSET and expressed at high level in Escherichia coli.Purified and refolded arresten protein could effectively inhibit proliferation of vascular endothelia cells.2 refs.

Development of a recombinant pB602L-based indirect ELISA assay for detecting antibodies against African swine fever virus in pigs

African swine fever(ASF),caused by the African swine fever virus(ASFV),is a devastating disease of domestic and wild pigs.There is no effective vaccine,and the control of the disease relies mainly on surveillance and early detection of infected pigs.Previously,serological assays,such as ELISA,have been developed mainly based on recombinant structural viral proteins of ASFV,including p72,p54,and p30.However,the antibodies against these proteins do not provide efficient protection against ASFV infection in pigs.Therefore,new serological assays that can be applied for clinical diagnosis and evaluating serological immune response in vaccinated pigs are still required.In this study,we expressed and purified a recombinant p B602 L protein.The purified p B602 L protein was then used as an antigen to develop an indirect ELISA assay.This assay has no cross-reaction with the anti-sera against the 15 most common pig pathogens in China,such as classical swine fever virus,pseudorabies virus,and porcine parvovirus.This assay and a commercial ELISA kit were then used to detect 60 field pig serum samples,including an unknown number of antiASFV sera.The coincidence of the two assays was 95%.Furthermore,the p B602 L-based ELISA was employed to test the antibody responses to the seven-gene-deleted ASFV strain HLJ/18-7 GD in pigs.The results showed that the antibody levels in all vaccinated pigs,starting from the 10 th day post-inoculation,have increased continuously during the observation period of 45 days.Our results indicate that this p B602 L-based indirect ELISA assay can be employed potentially in the field of ASFV diagnosis.

Secretory Expression of Recombinant Diphtheria ToxinMutants in B. Subtilis

Three diphtheria toxin (DT) mutants CRM-197, DT-del (148) and DT-El48S-K516A-F530A were cloned in B- Subtilis plasmid PSM604 under the subtilisin signal sequence. The expression was effective in both SMS300 and SMS118, but higher yield of 7. 1 mg/L was observed in SMS300 compared with 2. 1 mg/L in SMS118. Western blot showed that the recombinant protein could be effectively secreted into the culture medium as a 58 ku peptide, and could be de-graded into two peptides of 37ku and 21ku.

Preparation and immunogenicity of tag-free recombinant human eppin

Human epididymal protease inhibitor （eppin） may be effective as a male contraceptive vaccine. In a number of studies, eppin with an engineered His6-tag has been produced using prokaryotic expression systems. For production of pharmaceutical-grade proteins for human use, however, the His6-tag must be removed. This study describes a method for producing recombinant human eppin without a His6-tag. We constructed plasmid pET28a （＋）-His6-tobacco etch virus （TEV）-eppin for expression in Escherichia coli. After purification and refolding, the fusion protein His6-TEV-eppin was digested with TEV protease to remove the His6-tag and was further purified by NTA-Ni2＋ affinity chromatography. Using this procedure, 2 mg of eppin without a His6-tag was isolated from 1 I of culture with a purity of 〉95%. The immunogenicity of the eppin was characterized using male Balb/c mice.

Purification of Recombinant Porcine Interferon-Alpha

[ Objective] To study the purification of recombinant porcine interferon-alpha （rPolFN-alpha） and lay a foundation for researches on the structure of the rPolFN-alpha and the preparation of standard proteins. [ Method] The rPolFN-alpha were induced and extracted from the recombi- nant E. coil BL21, and they were purified by two strategies. The first strategy was that the rPolFN-alpha were purified by GST （ glutathione S transferase） affinity chromatography, DEAE （diethylaminoethyl） anion exchange chromatography and gel filtration in turn defined as three-step chromatography method; the second strategy was that the rPolFN-alpha were purified by GST affinity chromatography and gel filtration in tum defined as two-step chromatography method. Then the purified products were detected by the SDS-PAGE （sodium dodecyl sulfate polyacrylamide gel electrophoresis） and were identified by western-blotting. [Result] The purity quotient of pudfied products of the two-step chromatography method was 96.0% and that of the three-step chromatography method was 98.8%. The purified products were detected by the SDS-PAGE and the western- blotting, respectively. The results showed that the target band was 45.0 kDa and the specific band was found. [ Conclusion] The purity quotient of proteins of the two-step chromatography method is close to that of the three-step chromatography method, thus the two-step chromatography meth- od is more convenient and more suitable for pilot production than the three-step chromatography method.

Enhancing the treatment effects of tumor cell purified autogenous heat shock protein 70-peptide complexes on HER-3-overexpressing breast cancer

Objective The aim of this study was to enhance the treatment effect of tumor purified autogenous heat shock protein 70-peptide complexes(HSP70-PCs)on HER-3-overexpressing breast cancer.Methods In this study,we first studied the expression of HER-3 in breast cancer tissues and its relationship with patient characteristics.We then purified HSP70-PCs from primary breast cancer cells with different HER-2 and HER-3 expression profiles and determined the cytotoxicity of autogenous dendritic cells(DCs)and CD8+T cells induced by these complexes.Third,recombinant human HSP70-HER-3 protein complexes were used to inhibit the autogenous HSP70-PCs purified from HER-3-overexpressing breast cancer cells,and the resulting immunological response was examined.Results The results show that HSP70-PCs can be combined with recombinant HSP70-HER-3 protein complexes to induce stronger immunological responses than autogenous HSP70-PCs alone and that these treatments induce autogenous CD8+T cell killing of HER-3-positive breast cancer cells.Conclusion These findings provide a new direction for HSP70-DC-based immunotherapy for patients with HER-3-overexpressing breast cancer.

Development of Molecular Marker Linked with Cercospora Leaf Spot (CLS) Disease Resistance in Vigna radiata, Cloning, and Expression for Evaluating Antifungal Activity against Cercospora canescens

We developed a molecular marker for MAS of mungbean resistant varieties against CLS from the consensus sequence(MB-CLsRG)of identified RGAs(MB-ClsRCaG1 and MB-ClsRCaG2).The MB-CLsRG sequence-specific primer pair was used to screen Cercospora leaf spot(CLS)resistant varieties of mungbean in genomic analysis that showed congruency with phenotypic screening.Validation of molecular marker linkage with CLS resistance was performed using rtPCR in transcriptomic analysis.The sequenced PCR products showed 100%homology with MB-CLsRG sequence and putative disease resistance proteins that confirmed the linkage of molecular marker with CLS resistance in mungbean.The antifungal potential of MB-CLsRG gene encoding protein was assessed.The MB-CLsRG gene sequence was cloned in the E.coli expression vector for recombinant protein production.The recombinant protein was then investigated for its in vitro antifungal potential against Cercospora canescens.The in vitro investigation showed strong antifungal activity of recombinant protein as it restricted the growth of fungal mycelial mass.The results validated the linkage of developed marker with CLS-resistant mungbean varieties;therefore,it can be used to screen resistant varieties from a large population in MAS.Moreover,the recombinant protein of the MB-CLsRG gene sequence revealed antifungal potential,which proved the gene sequence could be suitable to use in transgenic plants technology to develop fungal-resistant transgenic crops.

重组戊型肝炎病毒衣壳蛋白工程菌的高密度培养

在 10L发酵罐中对戊型肝炎病毒衣壳蛋白在重组大肠杆菌中表达发酵工艺进行了研究 ,用分批培养方法探讨了不同培养基、培养基中磷酸盐浓度和Mg2 + 浓度等因素对菌体生长与重组蛋白表达的影响 ;用分批补料培养研究了不同的补料工艺对菌体生长与重组蛋白表达的影响 ,同时对重组菌诱导时期、诱导持续时间以及不同诱导温度表达包含体在尿素溶液中的溶解性进行了研究。结果表明 ,在优化后的培养基中 ,磷酸盐浓度、Mg2 + 浓度分别为 80mmol L与 2 0mmol L时菌体生长与表达效果较好 ;分批补料培养中 ,37℃培养 9h菌体达到对数期中期 (约 4 5OD6 0 0 )为适宜诱导时期 ,加入终浓度为 1 0mmol LIPTG后诱导 5h ,OD6 0 0 达到 80以上 ,重组蛋白表达量达到2 9 74 % ,为最适收获菌体时间 ;37℃表达的包含体 80 %以上溶解在 4mol L的尿素溶液中 ,最终浓度达到 14mg mL ;10L发酵罐中确定的发酵工艺参数在 30L发酵罐中进行了放大培养 ,10L发酵罐中确定的发酵工艺参数在 30L发酵罐上具有可放大性与重复性 ,可以应用于工业生产。

幽门螺杆菌VacA重组蛋白表达、纯化及鉴定

目的研究幽门螺杆菌空泡毒素(VacA)编码基因在大肠埃希菌中的表达及纯化重组蛋白的抗原性。方法将PET32 a-vacAE-.coliBL21(DE3)工程菌株常规培养,碱裂解法小量提取重组质粒DNA,琼脂糖凝胶电泳进行酶切鉴定,基因测序法进行插入基因序列分析。重组蛋白采用IPTG诱导表达,镍亲和层析原理提纯,ELISA法检测其抗原性。结果经酶切鉴定表明,插入的基因片段全长约2 240 bp,测序分析及与Genebank比较,可以肯定插入片段为vacA基因,ELISA法检测重组蛋白具有良好的抗原性。结论VacA重组蛋白在大肠埃希菌中成功表达,重组蛋白具有良好的抗原性。

MALDI-TOF-MS法对重组人内皮抑素蛋白分子质量测定

肿瘤的生长依赖于血管的生成,新生血管不仅为肿瘤生长提供必需的营养物质,而且为肿瘤细胞扩散提供了重要的途径[1].1997年哈佛大学的O'Reilly等[2]发现了一种内源性新血管生成抑制因子内皮抑素(Endostatin),显示出特异抑制激活的血管内皮细胞增殖和肿瘤新血管生成的生物学活性,其抗肿瘤作用具有高效、低毒、无耐药性的优点.……

A suspended cell line from Trichoplusia ni （Lepidoptera）： Characterization and expression of recombinant proteins

A suspended cell line from Trichoplusia ni embryos was established, and its susceptibility to Autographa californica multiple nuclear polyhedrosis virus （AcMNPV） infection was investigated. This cell line had characteristics distinct from the BTI-Tn5B 1- 4 cell line （Tn5B 1-4） from T. ni in growth, and showed approximately the same responses to AcMNPV infection, production of occlusion bodies, and levels of recombinant protein expression. No clumps were observed at maximum cell density at late-log phase in shake-flask or T-flask cultures, and thus the cells represent a useful new contribution for baculovirus research. The cells consist of two major morphological types： approximately 70% spindle-shaped cells and 30% round cells. The cell line was highly susceptible to virus infection and produced around 107 AcMNPV occlusion bodies per cell, on average. Production of β-galactosidase and secreted alkaline phosphatase was high with 3.97 ± 0.13 × 10^4 IU/mL and 3.48 ± 0.40IU/mL, respectively. This cell line may be applicable for studies of scale-up production of viruses or baculovirus-insect cell expression. We also believe the new line can be a source for cell clones with higher production of virus and recombinant proteins compared to the parent or other existing cell lines such as Tn5B 1-4.