PKR基因表达高效阻断Marc-145细胞系建立及其对PRRSV增殖的影响

研究猪繁殖与呼吸障碍综合征(porcine reproductive and respiratory syndrome, PRRS)在Marc-145细胞蛋白激酶R(interferon-induced, double-stranded RNA-activated kinase, PKR)下调表达状态下的感染特性。以Macr-145细胞PKR基因序列设计3个shRNA,并设阳性对照,合成后插入pSilencer^TM 2.1-U6载体构建重组质粒,与Macr-145细胞PKR+EGFP标签融合表达的重组质粒共转染HEK293细胞,以筛选能下调表达PKR的shRNA,并将该shRNA重组质粒转染Marc-145细胞,潮霉素B抗性筛选并克隆纯化获得PKR下调表达的细胞系,感染重组病毒PRRSV XZ06a-EGFP,通过检测病毒结构蛋白M与EGFP表达、观察细胞病变等,研究此状态下感染特性。结果显示筛选获得致使PKR下调表达的shRNA,以及稳定表达shRNA、PKR表达降低90%以上的Marc-145细胞系,重组病毒感染后48 h, M蛋白与EGFP表达均受到抑制,且...     

稳定高效表达猪CD163的Marc-145细胞系的构建与鉴定

试验旨在构建一株高效表达猪CD163(pCD163)的Marc-145细胞系,为猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)的临床分离和疫苗生产奠定基础。根据GenBank中序列设计引物从猪肺泡巨噬细胞(PAM)中扩增pCD163基因,将其插入真核表达载体pCI-neo构建真核表达质粒pCI-pCD163,将该重组质粒转染Marc-145细胞,通过G418筛选、单克隆化并扩大培养筛选获得表达pCD163的Marc-145细胞系,IFA、Western blotting鉴定其表达情况。IFA结果显示,构建的pCD163-Marc细胞系中荧光明显亮于普通Marc-145细胞;Western blotting结果显示,pCD163-Marc细胞系中CD163蛋白表达量约为对照Marc-145细胞中CD163蛋白表达量的8.7倍。且该细胞系可稳定传至20代,各代次之间表达量无差异。证明高效表达猪CD163的Marc-145细胞系构建成功。     

猴源cathepsin基因shRNA文库及其稳定敲减细胞系的构建

目前关于组织蛋白酶(cathepsin)在猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)生活周期中发挥功能的研究较少。为了探究宿主细胞中cathepsin在PRRSV吸附、入侵、脱壳、生物合成、组装以及释放过程中的作用,选取源于MA-104的非洲绿猴胚胎肾上皮细胞Marc145细胞系(对PRRSV易感);利用RNAi原理,构建了以pLKO.1为载体的cathepsin基因shRNA文库;并用puromycin筛选出稳定敲减cathepsin的细胞株。结果显示:本试验构建的cathepsin-shRNA文库包含45个克隆,涉及15种cathepsin基因,筛选出的稳定细胞株中相应cathepsin基因mRNA的表达量均有显著下降。这些细胞株的构建为进一步研究cathepsin在PRRSV生活周期中发挥的重要功能奠定了基础。     

苦参碱对PRRSV的体外抑制作用及其机制

本试验以Marc-145细胞为模型,采用细胞病变(CPE)抑制试验和MTT法测定细胞活力,观察苦参碱(matrine)体外抗猪繁殖呼吸与综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)活性,并从抑制病毒复制、阻断吸附和直接杀灭3个方面探讨苦参碱体外抑制PRRSV的作用机制.结果显示,苦参碱CC50＞1 500 mg/L,最大安全浓度为750 mg/L,EC50为(443.5±33.4)mg/L,SI≥3.38,在安全浓度范围内对PRRSV感染Marc-145细胞的抑制率达到93.6％;在直接杀灭和复制抑制试验中最高抑制率分别达到105.10％和91.53％;在病毒吸附抑制试验中抑制率＜20％,表明苦参碱不能阻断PRRSV对Marc-145细胞的吸附.结果表明,苦参碱在体外可有效抑制PRRSV对Marc-145细胞的感染,其抗病毒机制可能是干扰病毒的复制或/和直接杀灭病毒,提示苦参碱可作为研发预防及治疗猪蓝耳病的药物或先导化合物.     

稳定表达PRRSV N蛋白的Marc-145细胞系的构建

为了构建稳定表达猪繁殖与呼吸综合征病毒(PRRSV)N蛋白的Marc-145细胞系,以PRRSV全长感染性克隆为模板,通过PCR方法扩增PRRSV N基因,将N基因克隆到慢病毒载体中,获得重组质粒pLenti-CMV-N,利用三质粒慢病毒包装系统转染293T细胞,包装成表达N蛋白的慢病毒颗粒,将慢病毒颗粒转导至Marc...     

Marc-145细胞CD151蛋白主要抗原表位区的表达及其与猪繁殖与呼吸综合征病毒感染关系的研究

为研究CD151与猪繁殖与呼吸综合征病毒(PRRSV)感染的关系,根据GenBank中已发表的CD151蛋白的基因序列设计并合成一对特异性引物,从Marc-145细胞中扩增出294 bp的CD151基因片段并克隆入pGEX4T-3载体,转化人大肠杆菌用IPTG进行诱导表达,经SDS-PAGE和Western blot对表达产物进行鉴定.表达蛋白纯化后用于免疫小鼠制备抗CD151蛋白血清,用ELISA和IFA检测抗血清的效价及特异性.将抗CD151蛋白血清与Marc-145细胞孵育后再感染PRRSV,观察细胞CPE验证该血清对PRRSV的阻断效果.结果表明成功构建了pGEX4T-3-CD151,获得了相对分子质量为37 ku的重组CD151蛋白.制备的抗血清特异性结合Marc-145细胞并有效阻断PRRSV感染Marc-145细胞.这些研究结果为进一步阐明CD151与PRRSV感染的关系提供一定的理论基础.     

靶向SynDIG1的shRNA慢病毒载体的构建及功能鉴定

为了构建靶向突触分化诱导基因1(SynDIG1)的shRNA慢病毒表达载体,设计出SynDIG1的siRNA的靶点序列,并合成含干扰序列的双链DNA发卡结构shRNA,合成的Oligo经过退火分别与双酶切处理后的pLKO.1-GFP载体连接.将构建的重组质粒pLKO.1-GFP-SynDIG1 shRNA转化到DH5a...     

绵羊Myostatin基因shRNA慢病毒载体的构建与鉴定

针对绵羊Myostatin基因特异性序列,设计4对shRNA,并合成高表达载体。将干扰质粒和高表达载体瞬时共转染HEK293细胞,应用Real-time PCR鉴定干扰效率,将筛选到最有效的shRNA表达载体和pDONR221载体进行BP重组反应,以获得含干扰序列的入门载体。然后将含干扰序列的入门载体和慢病毒表达的目的载体pLenti6/BLOCK-iT-DEST进行LR重组反应,以获得含干扰序列的慢病毒表达载体。qPCR检测病毒物理滴度。结果本试验成功构建绵羊Myostatin基因RNAi慢病毒载体,病毒的滴度为：9.3×109 TU/mL。为研究Myostatin基因对肌肉生长的影响提供了稳定感染细胞载体。     

猪繁殖与呼吸综合征病毒GZ-KY1株的分离及ORF5基因的克隆分析

本试验首次采用PK-15细胞,通过同步接种的方法,成功分离到了1株猪繁殖与呼吸综合征病毒(PRRSV,GZ-KY1株),并扩增克隆了该毒株的ORF5基因。试验结果表明,该毒株ORF5基因全长603 bp,系美洲型,与国内强毒株的氨基酸一致性高于弱毒株,与经典美洲型毒株及国内弱毒株亲缘关系较远。     

家兔Zfx基因shRNA干扰载体构建及验证

研究主要是为了构建出针对家兔Zfx基因的shRNA重组载体及效果验证。根据家兔Zfx基因mRNA序列特征,设计出3条shRNA片段,再与线性化的pLL 3.7载体进行连接重组,最后经过qRT-PCR检测Zfx基因mRNA表达量筛选出有效重组表达载体并通过体内试验进行效果验证。结果表明:试验组shRNA-c和shRNA-f干扰效率分别为74%和67%,与空白对照组相比差异极显著(P<0.01);试验组shRNA-e干扰效果为17%,与空白对照组相比差异不显著(P>0.05)。用shRNA-c和shRNA-f进行体内试验,结果显示,两试验组雄性率分别为44.92%(P>0.05)和33.16%(P<0.01)。本试验成功构建针对家兔Zfx基因的重组载体,体内试验显示子一代出现性别偏移,说明Zfx基因对动物的性别决定有一定作用,关于导致体内验证出现反转的原因仍需进一步验证。     

猴源葡萄糖调节蛋白78生物信息学分析及其真核表达

试验旨在探究葡萄糖调节蛋白78（glucose regulatory protein 78,GRP78）基因的理化性质和结构特点,阐述GRP78在猪流行性腹泻病毒复制中的分子伴侣作用和调控机制。通过RT-PCR方法扩增GRP78基因,并插入到pMD20-T Simple载体进行克隆测序,利用生物信息学方法对其氨基酸序列、跨膜结构、糖基化位点、磷酸化位点、三级结构等进行预测和分析。将GRP78基因插入pCDNA 3.1中,然后转染Vero-E6细胞。Western blotting检测Vero-E6细胞中GRP78的表达。生物信息学分析结果表明,GRP78基因全长1 965 bp,编码654个氨基酸,蛋白质分子质量为72.33 ku,理论等电点为5.07,分子式为C₃₁₈₉H₅₁₅₃N₈₆₅O₁₀₁₉S₁₃。遗传进化树分析显示,猴源GRP78基因与双峰驼、犬、猫、大猩猩、蝙蝠、狒狒、猪、马的氨基酸序列同源性为99.5%~99.8%;遗传进化分析显示,大猩猩和狒狒亲缘关系最为接近。跨膜区和信号肽预测结果显示,该蛋白存在信号肽但不存在跨膜结构。GRP78蛋白无N-糖基化修饰位点,存在6个O-糖基化位点、28个磷酸化位点,表明GRP78可能有与激酶磷酸化有关的PKC、PKA特异性蛋白激酶的结合位点,可能参与己糖代谢和单糖代谢。     

转录靶向猪瘟病毒3''''-UTR shRNA细胞株的初步建立

利用质粒载体在细胞内转录并加工成siRNA的方法，设计3对针对猪瘟病毒3＇-UTR不同位点的干扰片段，分别与干扰载体pGenesil-1连接，转化DH5a，筛选阳性克隆得到重组干扰质粒pGene-1，pGene-2和pGene-3，脂质体介导转染重组干扰质粒于PK-15细胞，G418抗性筛选得到转录靶向猪瘟病毒3＇-UTRshRNA的PK-15细胞株，为今后应用RNAi研究猪瘟病毒Y-UTR调控病毒复制的功能以及抑制猪瘟病毒增殖的研究奠定了基础。     

Development and characterization of stable cell lines constitutively expressing the porcine reproductive and respiratory syndrome virus nucleocapsid protein

Despite global efforts to control porcine reproductive and respiratory syndrome virus (PRRSV) infection, the virus continues to cause economic problems in the swine industry worldwide. In this study, we attempted to generate and characterize a panel of stable BHK cell lines that constitutively express the nucleocapsid (N) protein of type 1 or type 2 PRRSV. The established BHK cell lines were found to react well with N-specific antibodies as well as the hyperimmune serum of pigs raised against each genotype of PRRSV. Taken together, the data implicate a potential usefulness for the newly generated stable cell lines as a diagnostic reagent for PRRSV serology.     

小鼠IGFBP-6基因shRNA的设计与筛选

胰岛素样生长因子结合蛋白6(IGFBP-6)是胰岛素样生长因子结合蛋白家族(IGFBPs)的一员,IGFBP 6不同于IGFBP1 5,其与IGF-2的亲和力显著的优先于IGF-1,受到研究者的广泛关注.本研究在小鼠IGFBP-6基因mRNA的806、760和908 bp处找到潜在靶位点,设计3条shRNA干扰载体,并合成DNA Oligo,体外退火成双链DNA,插入pGU6/GFP/Neo载体,获得3条针对目的基因不同靶序列的干扰载体,瞬时转染NIH-3T3小鼠胚胎成纤维细胞48 h后,利用流式细胞技术分选收集转染重组载体的细胞,提取细胞总RNA和蛋白质,实时荧光定量PCR和酶联免疫吸附法分别检测目的基因mRNA水平,蛋白水平对IGFBP-6的表达.结果表明,IGFBP-6(IGFBP-6,806-826)表现出了最高的干扰效率,转染效率为(79.2±2.3)％时,mRNA水平的沉默效率达(68.9±12.2)％,(P＜0.05);蛋白质水平的沉默效率达(46.7±11.3)％,(P＜0.05).本试验为研究IGFBP-6基因对细胞增殖的作用和体内生物学功能奠定了基础.     

稳定转染CD151或CD163的Marc145细胞系的建立及其在PRRS疫苗生产中的应用

为了进一步探讨提高PRRSV感染靶细胞滴度的有效方法,本研究采用脂质体介导方法,通过G418筛选稳定转染Marc145细胞,并利用单个细胞克隆技术,获得了稳定超表达CD151蛋白和(或)CD163蛋白的Marc145细胞株,经免疫荧光化学和Western Blot鉴定证实,成功表达出基因重组猪CD151蛋白和CD163蛋白。在GMP生产车间将超表达CD151、CD163蛋白或CD151/CD163蛋白共表达的Marc145细胞感染PRRSV,使病毒感染滴度提高了10倍以上。将上述收获的病毒液制备了灭活苗,疫苗效力超过部颁标准。     

猪带绦虫六钩蚴45W-4BX抗原的制备及其杂交瘤细胞株的建立

为获得针对猪带绦虫六钩蚴（TSO）45W-4BX抗原的杂交瘤细胞株,用IPTG对TS045W-4BX的重组质粒pGEX-4BX进行了诱导表达,并采用Sepharose-4B层析技术对表达产物进行纯化,运用SDS—PAGE和Western—blot分别对其纯度和活性进行了检测。分别用弗氏完全佐剂、弗氏不完全佐剂乳化已纯化的猪带绦虫TS045W-4BX重组抗原,随后用其分别免疫BALB／c小鼠3次,检测血清抗体效价呈阳性。之后,再进行加强免疫,取免疫小鼠脾细胞和SP2／0细胞进行融合,经TS045W-4BX抗原和GST抗原双系统间接ELISA筛选,最终获得了18株抗TS045W-4BX抗原的杂交瘤细胞株。采用有限稀释法对其中的4株进行5次亚克隆,最终获取了4株稳定分泌针对TS045W-4BX抗原的单克隆抗体的杂交瘤细胞株,金标试纸条法鉴定其抗体亚类均属于IgG1类,轻链为κ型。     

Analysis of the reactivity of anti-bovine CD8 monoclonal antibodies with cloned T cell lines and mouse L-cells transfected with bovine CD8

Mouse L-cells transfected with bovine CD8 and two Theileria parva-infected cloned T cell lines expressing bovine CD8 were used to screen the panel of ten monoclonal antibodies (mAbs) submitted to the workshop. Eight of the ten mAbs reacted with the transfectant and both the cloned T cell lines. However, two mAbs CC58 and BAT82A did not recognise the transfectant and only reacted with one of the T cell lines. Further biochemical studies indicated that the eight mAbs react with both homo- and heterodimeric forms of bovine CD8 whilst the two mAbs CC58 and BAT82A react with only heterodimeric forms. These data suggest that bovine DC8 is encoded by two genes as is the case in mouse and man.     

Construction of IGF-II shRNA Knockdown Vector and Its Effect on Sertoli Cells in Yak

The aim of this study was to construct shRNA recombinant vector interfering insulin-like growth factor-II (IGF-II), and study the effects of IGF-II on the yak sertoli cells. The shRNA oligonucleotides targeting yak IGF-II were designed and synthesized and it was cloned into pLKO.1 plasmid vector, after transfected into yak sertoli cells, a stable cell line was obtained by puromycin selection. The relative expressions of IGF-II mRNA and protein were identified by qRT-PCR and Western blotting, respectively. The proliferation and apoptosis of sertoli cells were analyzed by proliferation measurement system. The results showed that the pLKO.1-shRNA vector interfering IGF-II was successfully constructed, which was stably expressed in sertoli cells and could interfere the expression of yak IGF-II effectively. Compared with the control group, the interference efficiency of pLKO.1-shRNA2 was the most significant, IGF-II expression down-regulated to 19.1% (P<0.05), and could reduce the expression of endogenous IGF-II protein by 76.3% (P<0.05). The stable cell line obtained by transfection and screening of pLKO.1-shRNA2 plasmid had significant lower activity of cell division and proliferation than that of control group after 48 h of culture (P<0.05). The results of qRT-PCR showed that the expressions of IGF-I and IGF-IIR in sertoli cells were significantly up-regulated (P<0.05), and the expressions of IGF-IR and Bcl-2 were significantly down-regulated (P<0.05) after interfering IGF-II. In conclusion, the interference plasmids of IGF-II were successfully constructed. After interference plasmid was transfected into yak sertoli cells, it could effectively inhibit the expression of IGF-II, change the expression pattern of IGF-IR and Bcl-2, and potentially affect the division and proliferation of yak sertoli cells, however, the specific regulation mechanism requires further studied.