猪卵透明带—4蛋白在大肠杆菌中高表达的研究

目的：在大肠杆菌中高水平地直接表达目的蛋白,方法：用PCR方法从猪卵透明带－1(pZP1)cDNA中扩增pZP4目的基因片段,通过在其5′端和3′端引入的双酶切位点将该完整的目的cDNA定向插入pBV221表达质粒PRPL启动因子下游的多克隆区。结果：此重组表达质粒转化宿主工程菌后经热诱导培养,可在SDS－PAGE凝胶上得到特异性的高表达蛋白条带,而且它在Western blot鉴定实验中能被鼠抗pZP4的单克隆抗体17D3和兔抗pZP IgGs识别。结论：成功地在大肠杆菌高效表达了可被17D3单克隆抗体及ZP多克隆体识别的ZP4。     

B细胞表位人源化的猪ZP4在大肠杆菌中的表达与鉴定

近年来,以卵透明带为靶抗原的疫苗制备已从最初的卵透明带及其组分水平向更高层次发展.Minoru等发现用人工合成的LDPENLTL八肽B细胞表位片段与外源性T细胞表位所得嵌合肽免疫小鼠所得抗血清可有效抑制猪精卵结合试验,但对人精卵结合试验却效果甚差.     

结核分枝杆菌保护性肽表位KLIANNTRV多聚体重组表达及鉴定

目的 重组表达结核分枝杆菌保护性肽表位KLIANNTRV二聚体、四聚体、八聚体,以进一步探讨其免疫效应.方法 选取结核分枝杆菌抗原表位KLIANNTRV,引入Th表位PADRE及木马肽序列(RKKRRQRRR),并以RVKR序列作为接头,分别合成结核分枝杆菌保护性肽表位KLIANNTRV二聚体、四聚体、八聚体全基因序列,经PCR扩增后分别插入融合表达载体pGEX-4T-1,将重组质粒转人大肠杆菌BI21并以IPTG诱导表达,进一步经GST亲合层析柱纯化,经SDS-PAGE和Westerm-blot鉴定重组表达蛋白.结果 成功构建了结核分枝杆菌保护性表位KLIANNTRV二聚体、四聚体、八聚体的表达质粒,并经IPTG诱导表达了大小约为20000、32000、54000的融合蛋白.结论 结核分枝杆菌保护性肽表位KLIANNTRV多聚体的重组表达为进一步开发结核疫苗提供有价值的依据.     

人类白细胞抗原-G突变体cDNA克隆及在K562细胞上的表达

目的：克隆人类白细胞抗原-G(Human leukocyte antligen-G，HLA-G)突变体cDNA，并使其在HLA-I类阴性的K562细胞上获得稳定表达，为研究配-受体之间的识别机制奠定基础。方法：用RT-PCR方法从人子宫蜕膜组织扩增出HLA-GcDNA，得到全长HLA-GPCR产物后，用桥式PCR方法进行定点点突变，将突变的目的基因亚克隆于逆转录，将突变的目的基因亚克隆于逆转录mG-pLNCX表达载体，采用感染的方法将重组质粒转入K562细胞，最后经G418筛选及有限稀释，利用单克隆抗体W6/32进行FACS及mRNA检测，观察HLA-G突变体在靶细胞表面的表达。结果：HLA-G突变体分子在经mG-pLNCX转染的靶细胞表面获得稳定高表达。结论：成功构建了mG-pLNCX表达载体，并使HLA-G突变体分子在HLA-I类阴性的靶细胞K562细胞上获得稳定表达。     

HCG嵌合肽CP12基因的构建和原核系统表达

发展可组合靶抗原多个线性B细胞表位和自身或外源T细胞表位的基因工程嵌合肽免疫原,是当今疫苗学和免疫学界又一新的研究方向[1-3].我们曾以克服hCG避孕疫苗研制中存在的佐剂和免疫应答的MHC遗传限制等突出问题为目标,报道了hCG嵌合肽CP1编码基因的合成和原核生物表达的阶段性实验结果[4]. 本研究是系列基因工程hCG嵌合肽疫苗研究项目内容之一.其目的是,一在DNA和蛋白质分子设计水平积累提高靶CP肽在大肠杆菌中表达率的经验,二分析探讨所设计的不同表位组合顺序和CP肽链长度对其免疫原性的影响. CP12的分子设计与CP1的相似,即以同样顺序组合了hCGβ的3个线性B细胞表位和6个Th细胞表位(其中2个是广谱性的),区别是CP12在CP1的N端接上一段无B-和T-细胞表位的肽段, 它出自能在大肠杆菌中高表达的与人透明带1(ZP1)高度同源的猪ZP4肽的N端.CP12编码基因的构建分二步走,也就是,先化学合成正负链四段猪ZP4 25聚肽编码基因(含CP1编码基因5'端ATG后至BamH I位点间的短片段),两两配对退火复性后,通过酶促反应连接成1个ZP肽编码基因片段.然后再借助其两端EcoR I和BamH I酶切位点,重组插入经上述2种酶双酶切的pBV2 21-CP1重组表达质粒.DNA测序验证了CP12全序列.     

SIRT1及其突变体T200I、E420K真核表达载体的构建及鉴定

目的 克隆沉默信息调节因子1（SIRTl）基因的全长cDNA,构建含有SIRT1基因及其突变体T200I、E420K的重组真核表达载体,为进一步研究SIRT1基因功能奠定基础.方法 采用RT-PCR方法扩增SIRT1基因的全长cDNA,扩增产物通过双酶切将全长cDNA克隆到真核表达载体pcDNA3.1（＋）,得到pcDNA3.1 （＋）-SIRT1重组质粒;同时采用定点突变法构建其突变体pcDNA3.1 （＋）-T200I和pcDNA3.1（＋）-E420K表达载体.重组质粒经酶切鉴定和DNA序列测定,筛选出重组成功的真核表达载体.结果 成功克隆了SIRT1基因全长cDNA,并成功构建了pcDNA3.1 （＋）-SIRT1及其突变体的真核表达载体;阳性重组质粒酶切后经测序比对鉴定,与预期序列完全相符,转染293T细胞后可以表达带有HIS标签的SIRT1蛋白.结论 此方法可成功构建重组质粒pcDNA3.1（＋）-SIRT1及其突变体pcDNA3.1（＋）-T200I、pcDNA3.1（＋）-E420K真核表达载体,为SIRT1基因及其突变体T200I、E420K的生物学功能研究提供了基因材料.     

人T细胞免疫球蛋白黏蛋白-4 cDNA全长真核表达载体的构建及其在16HBE细胞中的表达

目的克隆人T细胞免疫球蛋白黏蛋白-4(TIM-4)基因cDNA,构建其真核表达载体pEGFP-C2-TIM-4,并转染16HBE细胞。方法根据GeneBank中人TIM-4 cDNA序列(编号:NM-138379.2),设计出带有EcoRI和BamHI的上下游引物,应用RT-PCR技术,从人骨髓中扩增出TIM-4基因编码区序列,克隆到pMD18-T载体,形成pMD18-T-TIM-4重组质粒,经菌落PCR,双酶切,测序鉴定获得人TIM-4基因cDNA片段,然后将其亚克隆入pEGFP-C2绿色荧光载体中,并通过菌落PCR,双酶切,测序鉴定其重组体。将测序正确的pEGFP-C2-TIM-4质粒转染人气道上皮细胞(16HBE),用实时定量PCR检测目的基因的表达。结果成功扩增出人TIM-4 cDNA全长1134 bp,经T-A克隆构建的pMD18-T-TIM-4重组质粒经菌落PCR,双酶切,测序证实载体中含有正确的TIM-4编码区片段。由此构建的真核表达载体pEGFP-C2-TIM-4,经菌落PCR扩增出1134 bp左右的片段,经双酶切后产生4.7 kb和1134 bp左右的2条带,DNA测序显示与GeneBan...     

小鼠端粒酶蛋白亚单位真核表达载体的构建和序列测定

目的： 克隆小鼠端粒酶蛋白亚单位(mTERT)的cDNA，构建真核表达载体并进行序列测定。 方法: 从肝癌细胞中提取总RNA，采用RT-PCR 技术扩增mTERT的基因编码区序列，将序列定向克隆至真核表达载体pAC，并进行序列测定。 结果： 获得mTERT编码区 3 369 bp的cDNA片段，用PCR和限制性内切酶分析鉴定，表明获得重组质粒pAC-mTERT。通过对mTERT编码区cDNA序列测序证实其与GenBank中的已知序列一致。 结论： 成功克隆了mTERT编码区序列，并构建了其真核表达载体，为以TERT为基础的肿瘤生物治疗奠定基础。     

人抗菌肽FALL-39突变体FALL-39-Lys24''32的构建及其抗菌作用研究

目的 :用PCR定点突变法构建人抗菌肽FALL 39基因突变体 pGEX 1 βT FALL 39 lys2 4’32 ,并比较研究FALL 39及其突变肽的功能。方法 :采用一步法和两步法PCR定点突变技术 ,用赖氨酸替代第 2 4位的谷氨酰胺和第 32位的天门冬氨酸 ,构建FALL 39突变体大肠杆菌表达载体 ;该载体表达的融合蛋白经亲合层析、凝血酶酶切和高效液相后获得高度纯化的FALL 39以及突变肽 ;用最低有效浓度 (MEC)、最低抑菌浓度 (MIC)、最低杀菌浓度 (MBC)指标比较纯化产物抗菌作用。结果 :PCR定点突变得到突变体质粒pGEX 1 βT FALL 39 lys2…     

Identification of Epitopes of Monoclonal Antibodies to Porcine Zona Pellucida 3β Glycoprotein,a Homologue of the Mouse/Human Sperm Receptor

PROBLEM: Immunization with zona pellucida (ZP) glycoproteins leads to a block in fertility with a variable degree of ovarian dysfunction. To avoid autoimmmune oophoritis, synthetic peptides corresponding to B cell epitope(s) and devoid of oophoritogenic T cell epitopes as immunogens have been proposed. The main objective of the present study is to define the epitopes recognized by monoclonal antibodies (mAbs) generated against porcine ZP3β, a homologue of the designated primary sperm receptor in mice and humans. METHODS: A multipin synthetic peptides approach has been used to map the epitopes recognized by mAbs. Dodecapeptides with an overlap of 6 amino acids corresponding to a precursor pZP3β-deduced amino acid sequence (excluding the signal sequence) were synthesized on polypropylene pins and were tested for their reactivity with mAbs by enzyme-linked immunoadsorbent assay (ELISA). The ability of synthetic peptides corresponding to the identified epitopes to inhibit the binding of mAbs to pZP3β in a competitive inhibition ELISA was investigated to confirm the above findings. RESULTS: Reactivity of the mAbs with the pin-bound peptides in ELISA-identified epitopes for mAb-451 to EEKLVF (166–171) and mAb-462/470 to FKAPRP (250–255) amino acid residues. mAb-30 recognized QPVWQDEGQRLR (23–34) and VICRCC (316–321) amino acid residues. Competitive inhibition with synthetic peptides encompassing the motifs corresponding to 23–34 and 316–321 for binding of mAb-30 to pZP3β revealed the epitopic domain to be 23–34 amino acids. Synthesis of overlapping octapeptides further identified WQDE as the minimum motif for binding of mAb-30, and the replacement of one amino acid at a time with glycine revealed tryptophan as the critical residue. CONCLUSIONS: Collectively, these results describe peptide epitopes that will help in the design of an immunocontraceptive vaccine based on synthetic peptides corresponding to pZP3β or its homologues in other species.     

Preimplantation embryology: The molecular genetics of the zona pellucida: mouse mutations and infertility

The zona pellucida is an extracellular matrix surrounding growingoocytes, ovulated eggs and the preimplantation embryo. Aftermediating the relatively species-specific events of fertilization,the zona pellucida provides a post-fertilization block to polyspermyand protects the growing embryo as it passes down the oviduct.The genes that encode the three zona pellucida proteins (ZP1,ZP2, ZP3) have been characterized in mouse and human. The abilityto genetically manipulate the zona pellucida genes in mousemodels has enhanced our knowledge of zona pellucida structureand function in vivo and may translate into a better understandingof human fertility. fertilization/infertility/transgenic mice/zona pellucida/ZP3 null mutation     

Blocking effect of antisera to recombinant zona pellucida proteins (r-ZPA) on in vitro fertilization

PROBLEM: The zona pellucida is a good target antigen for contraceptive vaccines due to its strong immunogenicity and high tissue specificity. However, this contraceptive effect is inevitably associated with ovarian failure. Therefore, it is necessary to define an epitope of the zona antigen to which the antibody produced inhibits fertilization without any undesirable side effects. METHOD OF STUDY: The DNA fragment coding for the NH2-terminal region of porcine zona pellucida proteins (ZPA) (1-198 amino acids) and human ZPA (1-206 amino acids) was prepared to produce recombinant porcine ZPA (r-ZPA), r-pZPA1-198 and r-hZPA1-206. Using Freund's complete adjuvant. antisera against these proteins were raised in rabbits. RESULTS: The resultant antisera to r-pZPA1-198 and r-hZPA1-206 were cross-reacted with each other on enzyme-linked immunosorbent assay and immunofluorescent staining. The antiserum to r-pZPA1-198 inhibited in vitro fertilization in pigs, but not human sperm binding to the zona pellucida, while the antiserum to r-hZPA1-206 inhibited the human sperm-binding assay. CONCLUSIONS: Antiserum to r-ZPA inhibited fertilization in the animal species possessing a homologous amino-acid sequence as an immunogen. The recombinant protein, r-hZPA1-206 seems to be a feasible candidate for the development of contraceptive vaccines for humans.     

Regulatory T-cell, endogenous antigen and neonatal environment in the prevention and induction of autoimmune disease

Summary: Recent studies on autoimmune ovarian disease (AOD) induced by thymectomy on d3 (d3tx), and AOD induced by immunization with the ovary-specific zona pellucida 3 peptide (pZP3), have yielded the following results. First, female tolerance to pZP3 depends on the persistence of endogenous antigen (Ag). Second, following regulatory T-cell depletion, endogenous Ag in prepubertal d3tx mice triggers AOD and drives disease progression. Third, endogenous ZP3 from ovaries without AOD stimulates a diversified IgG autoantibody (autoAb) response that rapidly follows pZP3 T epitope immunization. Fourth, induction of AOD and autoimmune memory in neonatal female mice by pZP3 in incomplete Freund's adjuvant depends on endogenous Ag stimulation within the neonatal week. Fifth, in a rodent pinworm-positive environment, neonatal but not adult female mice injected with pZP3 in water develop Th2-mediated AOD and Th2 memory. Sixth, neonatal T cells transfer AOD to syngeneic athymic recipients, whereas adult T cells are non-pathogenic and in fact suppress AOD conferred by neonatal T cells. Therefore: 1) the continuous presence of physiologically-expressed autoAg is critical for both tolerance maintenance and autoimmune disease pathogenesis; the outcome is determined by the integrity of regulatory T cells; and 2) the neonatal mice, deficient in the regulatory T-cell function, are more responsive than adults to Ag and environmental stimuli that promote autoimmune disease and memory.     

Four zona pellucida glycoproteins are expressed in the human

BACKGROUND: The zona pellucida (ZP) is an extracellular glycoprotein matrix which surrounds all mammalian oocytes. Recent data have shown the presence of four human zona genes (ZP1, ZP2, ZP3 and ZPB). The aim of the study was to determine if all four ZP proteins are expressed and present in the human. METHODS: cDNA derived from human oocytes were used to amplify by PCR the four ZP genes. In addition, isolated native human ZP were heat-solubilized, trypsin-digested and subjected to tandem mass spectrometry (MS/MS). RESULTS: All four genes were expressed and the respective proteins present in the human ZP. Moreover, a bioinformatics approach showed that the mouse ZPB gene, although present, is likely to encode a non-functional protein. CONCLUSIONS: Four ZP genes are expressed in human oocytes (ZP1, ZP2, ZP3 and ZPB) and preliminary data show that the four corresponding ZP proteins are present in the human ZP. Therefore, this is a fundamental difference with the mouse model     

Design and evaluation of a ZP3 peptide vaccine in a homologous primate model.

The concept of a safe, immunocontraceptive vaccine using the zona pellucida glycoprotein 3 (ZP3) as an immunogen has been marred by the appearance of ovarian dysfunction in several species. However, careful selection of epitopes on mouse ZP3 have demonstrated that it is possible to segregate contraceptive bone marrow-derived (B)-cell epitopes from the cytotoxic thymus-derived (T)-cell epitopes thought to be responsible for inducing ovarian disease. B-cell epitopes on marmoset ZP3 (mstZP3) were identified by epitope mapping studies. Using a panel of polyclonal antibodies against recombinant mstZP3, an immunodominant epitope mstZP3(301-320) was identified. A chimeric peptide was co-linearly synthesized incorporating this sequence with a promiscuous tetanus toxoid T-helper cell epitope. Using the common marmoset (Callithrix jacchus) as an animal model, we have compared the consequences of active immunization with homologous recombinant mstZP3 and mstZP3(301-320) chimeric peptide vaccine. Long-term infertility was achieved using mstZP3 but at the expense of ovarian function. In contrast, no disruption to ovarian function was observed following mstZP3(301-320) immunization. Antibodies to this peptide immunolocalized to the zona pellucida of both marmoset and human ovarian sections and inhibited human sperm-zona binding by approximately 60% in vitro. However, in-vivo studies indicated that targeting a single ZP3 epitope was insufficient to reliably and consistently achieve a contraceptive effect.     

不同人群血清中抗透明带抗体的检测

为了探讨抗透明带抗体的临床意义 ,本研究用纯化的猪卵透明带ZP3抗原制备抗卵透明带抗体酶联免疫检测试剂盒 ,采用ELISA方法检测不同人群血中抗透明带抗体 ,并用阳性血清与人卵巢组织切片进行免疫组化分析。结果显示不同年龄组妇女抗透明带抗体阳性率差异不显著 (P >0 0 5 ) ,不孕组阳性率 15 % ,与其他组相比有显著性差异 (P <0 0 5 )。ELISA检测到的透明带抗体阳性血清不与人卵巢组织切片中的透明带产生肉眼可见的沉淀反应。除了早孕组和老龄妇女 ,任何年龄阶段的女性均可出现抗透明带自身抗体 ,鉴于这些抗体不引起周期紊乱现象 ,却可能阻止受精 ,这为透明带作为避孕疫苗候选抗原的安全提供理论依据     

Lectin histochemical detection of sulfoglycans in the zona pellucida of mammalian antral oocytes

Sulphated esters are important to increase effectiveness of specific biological activities of carbohydrates. Biochemical studies revealed the presence of distinct sulphated glycoproteins in mammal zona pellucida (ZP) that bind proacrosin and thus participate in the sperm-egg fusion processes. In the present study, 6 lectin-horseradish peroxidase conjugates (SBA, PNA, RCA-I, GSA-IB4, GSA-II and DBA) were used in combination with desulphation and sialidase digestion to identify sulphocarbohydrates in the terminal and/or subterminal position of oligosaccharide side chains of glycoproteins in the ZP of bovine, ovine, caprine and porcine antral oocytes. In particular, we identified the following terminal sulphoglycans located in the outer layer of the ZP only: SO4-GalNAc in bovine ZP; SO4-Galbeta1,3GalNAc in bovine and ovine ZP; SO4-Galbeta1,4GlcNAc in bovine, ovine and caprine ZP; SO4-alpha-Gal in bovine, caprine and porcine ZP. Subterminal sulphoglycans linked to sialic acid residues were evenly distributed throughout the entire thickness of the ZP: Neu5Ac-SO4-Galbeta1,3GalNAc in bovine and porcine ZP; Neu5Ac-SO4-Galbeta1,4GlcNAc in caprine ZP; Neu5Ac-SO4-alpha-Gal in porcine ZP; Neu5AcSO4-GlcNAc in bovine ZP. The results demonstrate that the chemical composition of the ZP differs among species determining the species-specificity of gamete interactions.     

Species specificity of human and murine anti-ZP3 synthetic peptide antisera and use of the antibodies for localization and identification of ZP3 or ZPC domains of functional significance

The mammalian zona pellucida has an important function in the fertilization process. The zona pellucida protein 3 (ZP3 or ZPC) is the ligand for primary sperm binding and induces the acrosome reaction. In various species, ZP3 primary structures are highly conserved as revealed by cDNA cloning. The objective of these studies was to localize ZP3 protein using antisera generated against defined synthetic peptides that are specific for mouse or for human ZP3. Immunohistochemistry and transmission electron microscopy were applied to murine and human ovary sections. Immunochemical studies were performed in hemizonae pellucidae from microbisected human oocytes. Using the competitive hemizona assay and various anti-ZP3 antibodies, we further intended to identify human ZP3 epitopes of functional significance. Our results showed that antiserum AS ZP3-9 (mouse specific) detected mouse ZP3 protein in mouse oocytes and in immunoblots, whereas AS ZP3-14 (human specific) detected human ZP3 protein in human ovary sections, native hemizonae pellucidae and in immunoblots. ZP3 material was also detected in cumulus cells by immunohistochemistry. Ultrastructural studies showed an equal distribution of ZP3 throughout the zona pellucida. The human competitive hemizona assay revealed that none of the anti-ZP3 synthetic peptide antisera affected sperm binding suggesting that those epitopes are not involved in primary sperm binding. Anti-porcine ZP3 beta protein antibodies (polyclonal) blocked human sperm-zona pellucida binding. In summary, these anti-ZP3 synthetic peptide antibodies specifically reacted with intact ZP3 protein (murine and human) but did not inhibit human sperm-zona pellucida binding; anti-ZP3 antibodies can therefore be used as biomarkers for ZP3 localization and function.     

Anti-ZP3 Antibodies Binding to the Human Zona Pellucida: Effect of Oocyte-Storage Conditions

PROBLEM: The zona pellucida protein 3 (ZP3) is a zona pellucida (ZP) glycoprotein crucially involved in fertilization. ZP3 plays a major role in sperm binding and induction of the acrosome reaction. In different species, ZP3 proteins differ in their primary structure as derived from cDNA clones. The hemizona assay (HZA) is a bioassay that evaluates binding of human sperm to human ZP and is highly predictive of fertilization outcome under in vitro conditions. METHOD: In these studies, we used antisera generated against synthetic ZP3 peptides to compare antibody binding patterns to ZP with sperm-ZP binding capacity under different HZA conditions. RESULTS: Analysis of antibody binding to hemizonae derived from metaphase II human oocytes that were used either after refrigeration at 4°C or stored in a hyperosmotic salt solution revealed a strong reaction with human ZP3. However, treatment of human oocytes using a protocol to freeze embryos with the addition of 1,2 propanediol drastically reduced binding of ZP3 antibodies to the hemizonae. Nevertheless, no significant difference of sperm binding occurred under HZA conditions when oocytes were refrigerated, salt-stored, or frozen with 1,2 propanediol. CONCLUSIONS: Our results indicate that the ZP3 protein backbone might be altered by 1,2 propanediol-treatment while the glycoprotein-receptor remains intact. We conclude that antisera against ZP3 peptides can be used as markers for the ZP3 protein backbone in human oocytes and might be useful tools for the evaluation of ZP3 protein integrity.