腺相关病毒介导的仓鼠δ-SG基因在TO-2型仓鼠骨髓间充干细胞的表达

目的构建含有δ-SG基因的腺相关病毒载体并检测经腺相关病毒介导基因转染的TO-2型仓鼠骨髓间充质干细胞(MSCs)中目的基因的表达。方法用EcoRI酶和XhoI酶酶切含有δ-SG基因的pUC57-SG质粒,获得δ-SG基因。片段回收后定向插入腺相关病毒载体质粒pITR-GFP中重组成pITR-GFP-SG,并同pXX680、pHelper三质粒经钙磷沉淀法共转染HEK293细胞,斑点杂交法测定重组病毒颗粒滴度,再将重组病毒颗粒转染TO-2型仓鼠的MSCs,利用RT-PCR法,免疫荧光检测目的基因的表达,MTT检测转染细胞增殖能力。结果成功构建了δ-SG基因的腺相关病毒载体。含δ-SG基因的腺相关病毒感染TO-2型仓鼠MSCs48h后,RT-PCR产物经琼脂糖凝胶电泳出现884bp-DNA片段;免疫荧光检测显示TO-2型仓鼠MSCs中呈现绿色颗粒,大小深浅不一;MTT证实转染后细胞的增殖能力未受明显影响。结论采用腺相关病毒介导的方法,可以将δ-SG基因导入TO-2型仓鼠的MSCs并成功表达。     

胃癌相关基因GCRG213正反义真核表达载体的构建及鉴定

目的:构建胃癌相关基因GCRG213正、反义真核表达载体．方法:从pGEM-T质粒上扩增出的胃癌相关基因GCRG213的DNA片段,两端分别引入限制性内切酶KpnI,BamHI和EcoRI, BamHI识别位点．按正向、反向克隆入真核表达载体pcDNA3．1( )．测序正确的重组子pcDNA3．1-a(含GCRG213正向克隆), pcDNA3．1-b(含GCRG213反向克隆)和空载体经脂质体转染人胃癌细胞系MKN45细胞, G418筛选获得稳定转染的细胞株,采用半定量RT-PCR及Wlestern blot比较转染不同质粒的 MKN45细胞中GCRG213在mRNA和蛋白质水平上的表达差异．结果:经测序证实,GCRG213正向克隆和反向克隆正确插入真核表达载体 pcDNA3．1( ),组成重组子pcDNA3．1-a(含正向克隆),pcDNA3．1-b(含反向克隆)．重组子 pcDNA3．1-a,pcDNA3．1-b和空载体经脂质体转染人胃癌细胞系MKN45细胞,G418筛选获得稳定转染的细胞株．与对应的空载体比较,RT-PCR结果显示转染pcDNA3．1-a的 MKN45细胞中其mRNA的表达上调35．4％,而转染pcDNA3．1-b的MKN45细胞中其mRNA 的表达下调32．1％;Western blot结果显示转染 pcDNA3．1-a的MKN45细胞中其蛋白的表达上调49．4％,而转染pcDNA3．1-b的MKN45细胞中其蛋白的表达下调50．3％．结论:成功构建胃癌相关基因GCRG213正、反义真核表达载体．     

Cdx2基因RNA干扰慢病毒载体的构建与鉴定

目的:构建尾型同源盒基因Cdx2 RNA干扰(RNAi)慢病毒表达栽体并进行鉴定.方法:选取Cdx2基因的19 nt特异性序列,设计针对Cdx2的shRNA序列,应用基因重组技术插入到pLentiLox3.7(pLL3.7)慢病毒表达栽体中,Xba Ⅰ和Not Ⅰ进行双酶切和DNA测序鉴定重组克隆,重组病毒质粒及其3种辅助包装原件载体质粒通过LipofectamineTM2000共转染293T细胞,培养48 h后,收集细胞培养上清液,将其浓缩后在293T细胞中测定病毒滴度.结果:通过对pLL-Cdx2-shRNA载体进行双酶切鉴定,证实短发夹RNA正确插入慢病毒载体,DNA测序证实插入的序列正确,Cdx2基因RNA干扰重组慢病毒载体经293T细胞包装成功,收集293T细胞分泌的病毒上清测定病毒的滴度为5×107TU/mL.结论:成功构建A.Cdx2基因RNAi慢病毒栽体,为研究Cdx2对胃癌生长的影响提供了稳定感染细胞载体.     

胃癌相关基因GCRG213正反向转染和RNA干扰对裸鼠胃癌种植瘤的影响

目的:观察胃癌相关基因GCRG213体内正、反向转染和RNA干扰对裸鼠胃癌种植瘤的影响.方法:将对数生长期的胃癌细胞株MKN45接种到裸鼠皮下,成瘤后用制备好的分别含GCRG213正、反义克隆和RNAi片段的腺相关病毒分别在肿瘤局部注射,以空病毒和生理盐水对照,继续喂养2 wk后处死,取肿瘤测量重量,并用半定量RT-PCR检测肿瘤组织GCRG213mRNA表达水平.结果:裸鼠接种MKN45细胞3 wk左右皮下形成肿瘤结节.肿瘤组织重量在正向转染组为5.12±1.02g、反向组1.22±0.46g、RNAi组0.81±0.37g、空病毒组3.13±0.69g、生理盐水组3.45±0.87g;各组GCRG213 mRNA表达水平依次分别为0.406±0.01 3,0.211±0.021,0.087±0.015,0.312±0.050,0.283±0.061.结论:三种腺相关病毒分别有效地介导了GCRG213正、反义克隆和RNAi片段的体内表达,提高或降低了GCRG213 mRNA的表达水平,促进或抑制了胃癌种植瘤的生长.     

ECEL1基因PSCSI-GFP慢病毒载体的构建

目的设计并构建针对ECEL1基因的RNA干扰慢病毒载体。方法依照ECEL1基因为模板,设计RNA干扰靶点,根据选定的靶点序列,设计短发夹RNA(shRNA)干扰序列,在两端添加相应的限制性内切酶酶切位点,合成单链DNA oligo,退火缓冲液中配对形成双链DNA oligo。利用Age I和EcoR I双酶线性化GV115载体。把载体和DNA oligo相连接,其连接产物转化大肠杆菌感受态细胞,经PCR扩增并测序鉴定。再通过质粒抽提,转染,浓缩与纯化后获得重组的ECEL1基因RNAi慢病毒,用"HIV-1p24抗原ELISA法"测定样品滴度。选取检测合格的慢病毒感染人肝癌细胞(BEL-7404),并设置对照组,荧光观察感染率。并使用Real-time PCR法及Western blot检测人肝癌细胞(BEL-7404)中ECEL1基因敲减后mRNA和蛋白质的表达量。2组间比较采用两独立样本t检验。结果 (1)根据ECEL1基因模板设计后,选定psc48784片段作为RNA干扰靶点,制备双链DNA oligo,PCR鉴定阳性重组子并测序,验证psc48784为正确的克隆。经过质粒抽提,转染以及浓缩纯化后,成功构建ECEL1基因RNAi慢病毒。物理检测与无菌检测合格。(2)通过HIV-1 p24抗原ELISA法测定ECEL1基因RNAi慢病毒样品病毒滴,测定样品病毒滴度为3×108TU/ml;表明已成功构建高滴度且合格的ECEL1基因RNA干扰慢病毒。(3)用ECEL1基因RNAi慢病毒感染人肝癌细胞(BEL-7404),荧光观察结果显示细胞感染效率达到80%,细胞状态稳定;使用Real-time PCR的方法及Western blot检测实验组人肝癌细胞(BEL-7404)中ECEL1基因在mRNA和蛋白质水平的表达量受到抑制(P值均0. 05),敲减效率达到70. 5%。结论成功构建ECEL1基因PSCSI-GFP慢病毒载体并获得稳定高滴度的病毒样品,并获得稳定的ECEL1基因敲减的人肝癌细胞(BEL-7404)。     

编码小鼠分泌型Klotho蛋白的cDNA克隆及其重组腺相关病毒载体构建

目的 克隆编码小鼠分泌型Klotho蛋白(secKlotho)的全长cDNA片段,构建secKlotho重组腺相关病毒载体.方法 以小鼠肾脏组织mRNA为模板,通过RT-PCR扩增获得小鼠Klotho基因大片段并克隆至pMD18-T载体中,再采用长臂引物进行二次PCR扩增获得编码secKlotho的全长cDNA片段,经EcoR I/Xho I酶切、连接、转化将目的 片段亚克隆至腺相关病毒载体pAAV-MCS中,酶切及DNA测序对阳性克隆进行鉴定.结果 RT-PCR成功扩增出1 600 bp的小鼠Klotho基因大片段,经二次PCR扩增得到编码secKlotho 的全长1 650 bp cDNA片段,并最终获得3个序列信息和读码框完全正确的pAAV/secKlotho克隆.结论 成功构建小鼠分泌型Klotho重组腺相关病毒载体,为Klotho基因转染治疗慢性肾功能衰竭及冠状动脉粥样硬化等疾病奠定了基础.     

ezrin基因RNA干扰慢病毒表达载体的构建及其在人胃癌SGC-7901细胞系中的表达

目的构建ezrin基因RNA干扰慢病毒载体并建立ezrin基因稳定干扰的人胃癌SGC-7901细胞系,为ezrin基因的功能研究奠定基础。方法设计ezrin基因特异性RNA干扰靶序列,与PHR-SIN-CSGW-H1a载体定向连接,构建PHR-SIN-CSGW-H1a真核入门表达载体。通过与psPAX2和PMD2.G载体进行重组,获得ezrin基因真核表达重组慢病毒表达载体。利用包装细胞293FT获得重组的慢病毒,感染人胃癌SGC-7901细胞。结果成功构建PHR-Eai-psPAX2-PMD2.G真核表达慢病毒干扰载体并获得相应的慢病毒,病毒悬液的滴度>1×107U/L。RT-PCR、Western blot结果表明,ezrin基因mRNA及蛋白表达显著降低。结论成功构建人ezrin基因特异性的重组慢病毒干扰载体,获得ezrin基因稳定干扰的人胃癌SGC-7901细胞系。     

MHC Ⅱ类转激活因子基因的重组腺病毒载体的构建

目的 构建含有主要组织相容性复合物(major histocompatibility complex,MHC)Ⅱ类分子激活物(CⅡTA)基因的重组腺病毒载体.方法 回收CⅡTA的PCR产物插人pUC57中,用EcoR Ⅰ和Xho Ⅰ双酶切,U-Gene凝胶回收纯化3300bp目的基因片段.用EcoR Ⅰ和sal Ⅰ双酶切质粒载体pShuttle-GFP-CMV,用T4DNA连接酶将上述目的基因片段与pShuttle-GFP-CMV片段连接,得到穿梭质粒pShuttle-GFP-CMV-C Ⅱ TA,并经Kpn Ⅰ单酶切及测序鉴定.Ⅰ-Ceu Ⅰ/Ⅰ-See Ⅰ双酶切处理,回收目的片段,将pAdxsi载体片段和插入片段进行酶连接,得到腺病毒质粒pAdxsi-GFP-C Ⅱ TA,经Xho Ⅰ酶切鉴定后转染HEK293细胞并培养出毒.扩增、纯化重组腺病毒AdCⅡTA,并测定病毒滴度.结果 重组穿梭质粒pShuttle-GFP-CMV-C ⅡTA经Kpn Ⅰ单酶切及测序分析,证实与GeneBank中公布的小鼠CⅡTA(NM_007575)序列完全相符.重组腺病毒pAdxsi-GFP-C Ⅱ TA构建成功后在HEK293细胞中包装产生的重组腺病毒AdC Ⅱ TA对HEK293细胞有致病作用.经多次重复感染并纯化后,病毒滴度达2.0×10~(11)PFU/ml.结论 含小鼠CⅡTA基因的重组腺病毒已成功构建.     

人激肽释放酶腺相关病毒载体的构建及其在人脐静脉内皮细胞中的表达

目的研究人激肽释放酶腺相关病毒载体的构建,观察重组病毒感染人脐静脉内皮细胞株后人激肽释放酶基因的表达。方法将人激肽释放酶基因定向克隆入AAV载体质粒pAAV-MCS中,并与两种辅助质粒pAAV-RC和pHelper共转染293细胞,包装成带有人激肽释放酶基因的重组腺相关病毒(rAAV);收集病毒颗粒并测定病毒滴度。以不同滴度的病毒分别感染人脐静脉内皮细胞,逆转录聚合酶链反应定量检测人激肽释放酶在该细胞中的表达。酶联免疫吸附法测定人脐静脉内皮细胞内人激肽释放酶的含量。结果成功获得了重组人激肽释放酶基因AAV载体,重组病毒滴度为6.2×1010个/L。以滴度分别为1×109个/L、1×108个/L和1×107个/L的病毒感染人脐静脉内皮细胞,与空白对照组比较,人激肽释放酶的表达均有增加(P<0.05),但以1×109个/L组升高最明显(P<0.001)。结论带有人激肽释放酶的重组腺相关病毒滴度可以稳定地达到1010个/L以上,感染人脐静脉内皮细胞后,人激肽释放酶基因在宿主细胞中的表达明显增强。     

Residual risk of transfusion transmitted human immunodeficiency virus, hepatitis B virus, hepatitis C virus and human T lymphotrophic virus

BACKGROUND: The risk of transfusion transmitted viral infection is now so low that mathematical modelling is required to estimate the residual risk. The first national viral risk estimates for hepatitis B virus (HBV), human immunodeficiency virus (HIV) and hepatitis C virus (HCV) were recently published by the Australian Red Cross Blood Service. Using several refinements to the original methodology, as well as an additional 2 years of data, new risk estimates have been derived. METHODS: Viral screening data for Australian donors for 2000/2003 were retrospectively analysed. The data were applied to three published models to estimate the residual risk of transmitting HIV, HBV, HCV or human T lymphotrophic virus (HTLV) by blood transfusion in Australia. RESULTS: Applying the three models to HBV, HIV and HCV, three point estimates of the residual risk per unit were calculated for each virus. The median point estimates were 1 in 1,339,000 for HBV, 1 in 1 in 7,299,000 for HIV, and 1 in 3,636,000 for HCV. Although the HTLV risk could not be equivalently calculated because of the lack of incident infection it was estimated to be considerably less than 1 in 1,000,000 using a separate method. CONCLUSIONS: The most current and accurate estimate of residual risk of viral transmission in Australia has been provided in the present study. The residual risk in Australia is exceptionally small, continuing to decrease and is generally less than European or US risk estimates. These new estimates demonstrate that for viral transmission the Australian blood supply is amongst the safest in the world, and provide a basis for evaluating the cost benefit of future viral testing methodologies.     

两种新发现的脑炎病毒

1994年爆发了两次能感染马和人类的一种新的病毒性疾病 ,引起昆士兰和澳大利亚 2 3匹马和 3人感染 ,其中一人死于爆发的呼吸道疾病 ,另一人死于脑炎 ,第三位患者出现流感样症状并完全康复 ,引起该病的病毒最初称为马麻疹病毒 (ｅｑｕｉｎｅｍｏｒｂｉｌｌｉｖｉｒｕｓ ,ＥＭＶ) ,后命名为Ｈｅｎｄｒａ病毒。 1998年 9月下旬至1999年 6月中旬在马来西亚爆发的一种病毒性脑炎 ,发病例数高达 2 65例 ,其中 10 5例死亡。绝大多数患者是养猪场或屠宰场工人。 1999年 3月 10日～ 19日在新加坡 1个屠宰场的 11名工人出现脑炎或不典型肺炎的临床表现…     

GB virus C/hepatitis G virus

GB virus C (GBV-C), or hepatitis G virus (HGV), is a recently discovered enveloped RNA virus belonging to the Flaviviridae family. GBV-C/HGV is transmitted by contaminated blood and/or blood products, intravenous drug use, from mother to child, sexually, and possibly through close social contacts. Several reports indicate a high prevalence of GBV-C/HGV viremia (1-4%) within healthy populations in Europe and North America, and an even higher prevalence (10-33%) among residents in South America and Africa. GBV-C/HGV has been suggested to be a causative agent for non-A-non-E hepatitis. However, several contradictory observations suggest that its ability to cause hepatitis is questionable. Taken together most data suggest that GBV-C/HGV is not a major cause of liver disease despite recent data indicating that it may infect and replicate in hepatocytes.     

Antigens of human T-lymphotropic virus type III/lymphadenopathy-associated virus

Antigens encoded by the gag and env genes of the human T-lymphotropic virus type III/lymphadenopathy associated virus (HTLV-III/LAV) include a p55 gag polyprotein that yields p24 as the major virus core protein, and an env gene polyprotein, gp 160, that produces gp 120, the most immunogenic protein in humans, at the amino terminus. Although its use is limited to research laboratories due to the cost and specialized procedures involved, the analysis of sera by radioimmunoprecipitation and sodium dodecyl sulfate-polyacrylamide gel electrophoresis is the test providing the optimal balance of specificity and sensitivity. Because the gp 120 represents the external virus protein, it would be the most appropriate antigen for vaccine development. Also viruses serologically related to HTLV-III/LAV were detected recently in two species of Old World monkeys. Because about half the healthy African green monkeys appear to have been exposed to simian T-lymphotropic virus type III (STLV-III), a related agent of the species, a characterization of the STLV-III gp 120 and immune response of the host may provide additional information for vaccine development.     

Directed evolution of adeno-associated virus to an infectious respiratory virus

Respiratory viruses evolve to maintain infectivity levels that permit spread yet prevent host and virus extinction, resulting in surprisingly low infection rates. Respiratory viruses harnessed as gene therapy vectors have illustrated this limitation. We used directed evolution in an organotypic human airway model to generate a highly infectious adeno-associated virus. This virus mediated gene transfer more than 100-fold better than parental strains and corrected the cystic fibrosis epithelial Cl⁻ transport defect. Thus, under appropriate selective pressures, viruses can evolve to be more infectious than observed in nature, a finding that holds significant implications for designing vectors for gene therapy and for understanding emerging pathogens.