抗半胱氨酸蛋白酶-7核酶的克隆、体外表达与切割活性的研究

目的 设计并合成抗小鼠半胱氯酸蛋白酶-7(Caspaso7)的锤头状核酶,并对它们的体外表与体外切割活性进行研究。方法 采用计算机软件对锤头状核酶和小鼠Caspase 7基因的二级结构进行分析,核酶的DNA序列在体外由自动合成仪合成,小鼠Caspase-7日的基因通过RTPCR扩增获得,将核酶基因和caspase-7基因分别克隆入载体pBSKneoU6’和pGEM-T中,通过体外转录得到核酶和caspase-7 mRNA,通过体外切割筛选出具有切割活性的核酶。结果 针对目的基因的333和394位点设计合成了两个核酶：Rz333和Rz394。成功获得caspase-7 mRNA的表达载体PC7及含有核酶的重组质粒PU6Rz333和pU6Rz394,通过体外转录表达出含有caspase7mRNA的987nt的靶mRNA及完整的核酶Rz333(47nt)和Rz394(50nt)。体外切割实验证实Rz333能够定点切割caspase-7mRNA,产生243nt和744nt的切割产物,切割效率为67．98％。Rz394不能切割靶基因。结论 核酶Rz333能够位点特异性的切割caspase-7 mRNA。     

HDV核酶对人肝癌细胞端粒酶组分阻断作用的研究

目的:观察HDV核酶对人肝癌细胞端粒酶RNA组分的阻断作用。材料与方法:人工设计和合成了HDV核酶的序列,构建体外转录载体PGEM.RZ。提取人肝癌7402细胞端粒酶cDNA序列并构建体外转录质粒PGEM hTR。将上述质粒转录,测定了不同条件下HDV核酶对端粒酶的切割效力及其动力常数Kcat,Km及Kcat/Km的值。结果:核酶对底物的最大剪切效率为70.4％。在同一种离子存在的条件下,Km随温度而升高,Kcat则始终在0.71～1.3/min之间波动。结论:HDV核酶(g.RZ57)对人肝癌细胞端粒酶 RNA组分具有体外切割效力,其可以用来切割端粒酶等异源性RNA分子,可作为潜在的肿瘤治疗抑制剂。     

针对端粒酶的HDV核酶的设计及其对端粒酶活性抑制研究

设计针对端粒酶的HDV核酶，观察其对端粒酶活性抑制。设计和合成了针对端粒酶组分的HDV核酶的序列，构建了该核酶的体外转录和真核表达质粒，检测了HDV核酶对端粒酶组分的体外切割效力和对端粒酶活性的抑制作用。核酶对底物的最大剪切效率为70．4％。导入细胞后，使端粒酶活性下降90％。HDV核酶(g．RZ57)对端粒酶活性有抑制作用，可望成为有效的肿瘤治疗抑制剂。     

丁型肝炎病毒核酶结构改建及其对丙型肝炎病毒RNA的剪切活性

目的 观察经过结构改建的丁型肝炎病毒核酶（HDV核酶）对丙型肝炎病毒（HCV）基因组RNA是否存在剪切作用。方法 对HDV基因组核酶的茎IV区和底物结合区进行改建,获得3种针对HCV RNA的HDV核梅RzCI、RzC2和RzC3。体外转录制备含HCV RNA 5′－非编码区（5′-noncoding region,5′-NCR)及部分C区的底物RNA（HCV RNA5′-NCR-C）,进行5′端放射性标记。在一定的pH、温度、Mg^2 浓度和有或无去离子甲酰胺存在等条件下,将核酶和底物按摩尔比100：1混合,反应2h后聚丙烯酰胺凝电泳,放射自显影,推算剪切百分率。结果 RzCI和RzCI2可剪切HCV RNA5′-NCR-C,在适宜浓度的去离子甲酰胺存在时剪切效率较高,RzC3对底物几乎无剪切活性。结果 设计得当的HDV基因组核酶可以剪切异源性RNA分子HCV RNA。     

HDV核酶对人肝癌细胞端粒酶组分阻断作用的研究

目的：观察HDV核酶对人肝癌细胞端粒酶RNA组分的阻断作用。材料与方法：人工设计和合成了HDV核酶的序列，构建体外转录载体PGEM．RZ。提取人肝癌7402细胞端粒酶cDNA序列并构建体外转录质粒PGEM hTR.将上述质粒转录，测定了不同条件下HDV核酶对端粒酶的切割效力及其动和常数Kcat,Km及Kcat/Km的值。结果：核酶对该物的最大剪切效率为70．4％。在同一种离子存在的条件下，Km随温度而升高，Kcat则始终在0．71－1．3/min之间波动。结论：HDV核酶（g.RZ57)对人肝癌细胞端粒酶RNA组分具有体外切割效力，其可以用来切割端粒酶等异源性RNA分子，可作为潜在的肿瘤治疗抑制剂。     

反式HDV核酶对肝癌细胞端粒酶活性抑制的研究

目的 观察HDV核酶是否能有效切割肝癌细胞端粒酶组分及在细胞内使端粒酶活性抑制。方法 设计合成针对端粒酶组分的HDV核酶的序列，构建该核酶的体外转录和真核表达质粒，测定HDV核酶对端粒酶的体外切割效力和在细胞内对端粒酶活性的抑制。结果 HDV核酶对底物的最大体外剪切效率为70％。导入细胞后，使端粒酶活性下降90％。结论H DV核酶(g．RZ57)对人肝癌细胞端粒酶活性有抑制作用，可望成为新型的肿瘤抑制剂。     

HBV特异性核酶与HDV重组体的体外转录及切割活性研究

目的利用基因重组技术,用核酶基因置换HDV部分基因,分别用HBV特异性核酶(rRZ)和核酶-HDV重组体(rHDVRZA、rHDVRZB和rHDVRZC)研究体外转录与剪切HBV的活性。方法 将含有83lbp的HBV C基因片段的质粒pTA-HBV用BamHI消化成线性后,体外转录获取5’端32P标记靶HBV C RNA。将获得的3个核酶-HBV重组体rHDVRZA、rHDVRZB和rHDVRZC克隆于pGEM-T载体T7启动子下游进行非标记的大量转录。分别将rRZ、rHDVRZA、rHDVRZB和rHDVRZC与卫32P-HBV C RNA按一定比例和条件保温切割。结果 体外实验证明rRZ、rHDVRZA、rHDVRZB和rHDVRZC在37℃具有酶切活性。提示所设计的核酶-HDV重组体rHDVRZA和rHDVRZB中核酶结构正确。结论在HDV基因组不同位置插入核酶,能够维持酶正确结构的核酶-HDV具有体外特异性切割HBV的活性。     

U1 snRNA嵌合体核酶的抗丙型肝炎病毒作用

目的鉴定特异性抗丙型肝炎病毒(HCV)核酶与具有细胞核靶向性的U1 snRNA组成的嵌合体在体外切割HCV RNA的活性。方法通过聚合酶链反应及克降的力。法用HCV特异性核酶(Rz)序列戢代质粒pBSIISK U1(含有人类野生型U1 snRNA基因全序)中U1 snRNA第三个茎环结构，重组质粒命名为pBSIISK (U1-Rz)。再将pBSIlSK (U1-Rz)中核酶与U1 snRNA组成的嵌合体基因止向充隆于pGEM-T载体T7启动子的下游，重组质丰立命名为pGFM(U1-Rz)。质粒pGEM-(U1-Rz)和pGEM Rz[含有与pGEM(U1-Rz)相同的核酶序列]体外转录后，转录产物与靶RNAs在一定条件下进行切割反应，电泳后放射自显影。结果U1 snRNA嵌合体核酶构建成功。嵌合体核酶与核酶对靶RNAs均有切割活性，且二者的切割活性相似。随着时间的延长和工具酶体积比的增加切割效率增加。结论特异性抗HCV核酶与U1嵌合体在体外具有良好的持异性催化切割活性。     

丙型肝炎病毒特异性锤头样核酶体外转录及切割活性的初步研究

目的　研究针对丙型肝炎病毒 (HCV)特异性锤头样核酶 (Rz)的体外转录及切割活性。方法　设计 3种锤头样核酶 :Rz1、Rz2 分别作用于HCVRNA 5′ 非编码区 (5′ NCR)上核酸序列 136～16 0、313～ 337,Rz3 作用于核心 (C)区上核酸序列 373～ 388。为区别于反义核酸的封闭作用 ,设计在Rz3 的催化环上存在点变异 (G取代A)的变异核酶Rzm用作对照。体外转录出靶HCVRNA和核酶RNA ,在一定条件下 ,将3 2 P标记的靶HCVRNA与核酶RNA按不同浓度比例进行切割反应 ,电泳后放射自显影 ,通过同位素扫描成像分析仪分析来评价核酶切割效率。结果　除Rzm外 ,在生理温度下 ,3种核酶均有活性 ,并随核酶浓度增加而提高 ;核酶切割靶位点距HCV起始密码子近切割效率高。结论　设计并观察到体外具有HCV特异性切割活性的锤头样核酶 ,为进行核酶的细胞内应用研究奠定基础     

抗Caspase-12核酶的制备与体外活性鉴定

目的 设计针对小鼠内质网应激凋亡途径中caspase-12mRNA的锤头状核酶(Rz138、Rz218)，通过靶基因及核酶的体外转录、切割，进行核酶活性鉴定，评估其应用前景。方法 小鼠Caspase-12基因的逆转录聚合酶链反应(RTPCR)扩增片段克隆于PGEMT载体的T7启动子下游，通过α-^32P UTP标记的体外转录物作为靶RNA。设计合成针对小鼠Caspase-12 mRNA的核酶，通过PCR方法扩增核酶的转录模板，采用非同位素标记法行体外转录，核酶与靶RNA进行体外切割实验。结果在37℃，Rz138、Rz218均有切割活性，Rz138的切割效率较高，几乎100％。结论 Rz138在体外具有良好的特异催化切割活性，它有望通过切割Caspase-12 mRNA而抑制内质网应激介导的细胞凋亡发生。     

Clinical characteristics and distribution of genotypes of TT virus infection in a hepatitis C virus-hyperendemic township of a hepatitis B virus-endemic country (Taiwan)

BACKGROUND: The prevalence of TT virus (TTV) viremia, without definite clinical significance, has been reported to be higher among chronic hepatitis C patients. The status and clinical characteristics of TT virus (TTV) infection and distribution of TTV genotypes in a hepatitis C virus (HCV) hyperendemic township (Masago community) in a hepatitis B virus (HBV) endemic country (Taiwan) were investigated. METHODS: Sera from 100 Masago residents were tested for alanine aminotransferase (ALT) and markers of HBV, HCV and GB virus C/hepatitis G virus (GBV-C/HGV) and TTV-DNA. Sera of 250 blood donors as a control group were tested for TTV-DNA. Sera of Masago residents and blood donors with positive TTV-DNA were directly sequenced, and phylogenetic analyses were performed subsequently. RESULTS: The prevalences of TTV viremia in different age groups among individuals from Masago were significantly higher than that among blood donors. In regard to the subtypes of TTV, 23, seven, two, eight, one, six and one isolate were related to the genotypes 1a, 1b, 2a, 2b, 3, 4 and 5, respectively, from Masago and 21, 14, one, nine and three isolates were related to the genotypes 1a, 1b, 2a, 2b, and 4, respectively, from donors. No clinical or virological factor was associated with TTV viremia or TTV genotypes. CONCLUSIONS: TT Virus prevalence was higher among HCV hyperendemic township residents than blood donors with similar genotype distributions (genotype 1 was the most prevalent) in Taiwan. Neither TTV viremia nor a particular genotype was associated with HBV, HCV or GBV-C/HGV infection and abnormal ALT levels.     

临床肝病患者中庚型肝炎病毒(GBV-C/HGV)的感染

本文应用抗-HGV酶联免疫法(EIA)和逆转录套式聚合酶链反应法(RT-PCR)检测150份乙型、120份丙型、15份戊型和49份非甲-戊型肝炎患者血清。结果显示:乙肝、丙肝、戊肝和非甲-戊型肝炎患者中抗-HGV抗体的阳性率分别为22.0％(33/150)、25.0％(30/120)、33.3％(5/15)和40.1％(20/49)。其中乙型、丙型、戊型和非甲-戊型肝炎的抗-HGV抗体阳性者中,HGV RNA的阳性率分别为58.3％(7/12)、60.0％(6/10)、40.0％(2/5)和45.5％(9/12)。说明GBV-C/HGV可与HBV、HCV或HEV合并感染,该病毒可能引起临床型肝炎。     

{alpha}V{beta}3-integrin routes herpes simplex virus to an entry pathway dependent on cholesterol-rich lipid rafts and dynamin2

HSVs enter cells in a receptor-dependent [nectin1 or herpesviruses entry mediator (HVEM)] fashion by fusion of the viral envelope with plasma membrane (neutral pH compartment), by endocytosis into neutral or acidic compartments, or by macropinocytosis/phagocytosis. The cellular determinants of the route of entry are unknown. Here, we asked what cellular factors determine the pathway of HSV entry. CHO cells lack β(3)-integrin and the respective α-subunits' heterodimers. We report that, in the absence of α(V)β(3)-integrin, HSV enters CHO-nectin1 cells through a pathway independent of cholesterol-rich rafts and dynamin2. In the presence of α(V)β(3)-integrin, HSV enters CHO-nectin1 cells through a pathway dependent on cholesterol-rich rafts and dynamin2. HSV enters J-nectin1 and 293T cells through a neutral compartment independent of cholesterol-rich rafts and dynamin2. α(V)β(3)-integrin overexpression in these cells modifies the route of entry to an acidic compartment dependent on cholesterol-rich rafts and dynamin2, hence similar to that in α(V)β(3)-integrin-positive CHO-nectin1 cells. In some cells, the diversion of entry from an integrin- and raft-independent pathway to an acidic compartment requiring cholesterol-rich lipids rafts and dynamin2 is irreversible. Indeed, HSV cannot infect CHO-nectin1-α(V)β(3) cells through any compartment when the αvβ3-integrin-dependent pathway is blocked by anti-integrin antibody, anti-dynamin2, or anti-acidification drugs. We conclude that the αvβ3-integrin is a determinant in the choice of HSV entry pathway into cells. Because the pathway dictated by αvβ3-integrin is through lipid rafts, the platforms for a number of Toll-like receptors, current findings raise the possibility that αvβ3-integrin acts as a sentinel of innate immunity.     

2665例急性上呼吸道感染患儿的病原学及临床特征

目的 分析急性上呼吸道感染儿童患者的病原学及临床特征。方法 以南方医科大学珠江医院2009年11月至2015年9月收治的2 665例急性上呼吸道感染儿童为研究对象,采用qRT-PCR方法检测临床上常见的8种呼吸道病毒(流感病毒、呼吸道合胞病毒、副流感病毒、腺病毒、人类博卡病毒、人类冠状病毒、人类偏肺病毒、鼻病毒)。结果 共检测患儿标本2 665份,其中阳性标本1 566份,总阳性率为58.8%。四个季节中8种呼吸道病毒检出率存在明显差异,并以春季最高,夏冬季次之,秋季最低。儿童呼吸道病毒感染率随着年龄增加而逐渐降低,并以0~1岁婴幼儿病毒检出率最高64.5%。男童呼吸道病毒感染率高于女童,住院患儿呼吸道病毒检出率高于门诊患儿。混合感染标本260份,占阳性标本数的16.6%,主要集中于0~3岁儿童患者标本中,并因季节而异,秋冬季节较少,而春夏季节较为普遍。咳嗽为呼吸道病毒感染的主要临床症状,咳痰和流涕次之,临床症状在8种呼吸道病毒感染患儿中存在差异。结论 本调查分析了急性上呼吸道感染患儿中8种常见呼吸道病毒的病原学及临床特征,为指导临床治疗及防控提供相关数据。     

Selection of HSV capsids for envelopment involves interaction between capsid surface components pUL31, pUL17, and pUL25

During egress from the nucleus, HSV capsids that contain DNA (termed C capsids) are preferentially enveloped at the inner nuclear membrane over capsid types lacking DNA. Using coimmunoprecipitation and biochemical analyses of wild-type and mutant capsids, we identify an interaction between a complex of pU(L)17/pU(L)25, termed the C capsid-specific complex (CCSC), and pU(L)31, a component of the nuclear egress complex (NEC). We also show that the interactions between these components are dependent on expression of all three proteins but occur independently of the pU(L)31 interacting protein and NEC component pU(L)34, as well as a kinase encoded by U(S)3 that phosphorylates both pU(L)31 and pU(L)34. The interaction between the CCSC and pU(L)31 in the NEC suggests a mechanism to conserve viral resources by promoting assembly of only those viral particles with the potential to become infectious.     

各型肝炎病毒单纯及重叠感染的研究

目的 探讨病毒性肝炎患者甲～戊，庚型肝炎病毒(HAV-HEV，HGV)单纯感染及重叠感染情况。方法 采用EIA法检测病毒性肝炎患者血清抗-HAV IgM，HBV标志物、抗-HCV IgM、抗-HDV IgM、抗-HEV IgM、抗-HGV IgM。结果 共检测210例病毒性肝炎患者HAV-HEV、HGV血清标志物，20例未检出(9．5％)，190例患者检出标志物阳性(90．5％)。HBV感染率89，5％(188／210，其中有34例为既往感染，占16．2％，现症感染154例，占73．3％)；HAV感染率29．0％(61／210)，HCV、HDV感染率均为8．1％(17／210)、HEV、HGV感染率依次为10．0％(21／210)、7．1％(15／210)。各临床类型中单纯感染占61．4％(129／210)，二重感染占32．4％(68／210)，以HAV HBV、HBV HDV、HBV HEV感染模式最常见，三重感染占6．2％(13／210)，以HAV HBV HDV感染模式最常见；临床上以肝炎肝硬化、重型肝炎重叠感染常见，急性肝炎最少见。结论 病毒性肝炎中HBV感染最常见，其次为HAV感染；单纯感染、二重感染多见，三重感染少见；重叠感染发生率随病情加重而增加。     

Interferon treatment of two patients with quadruple infection with hepatitis C virus (HCV), human immunodeficiency virus (HIV), hepatitis G virus (HGV), and TT virus (TTV)

Abstract: We administered interferon (IFN) to two patients who had quadruple infection with hepatitis C virus (HCV), human immunodeficiency virus (HIV), hepatitis G virus (HGV), and TT virus (TTV), a recently isolated novel DNA virus. Nine mega-units of natural alpha-IFN were administered daily during the first two weeks and thrice weekly during the following 22 weeks (total dose, 720 mega-units). In both cases, serum alanine aminotransferase (ALT) levels decreased during IFN administration but increased thereafter. The concentrations of HCV, HIV, HGV, and TTV declined with the administration of IFN. However, the concentrations of these 4 viruses increased after the cessation of IFN with the except of TTV in patient 2 which disappeared during treatment and did not subsequently reappear. IFN reduced the concentrations of 4 viruses, in an apparently independent manner.     

Effects of HAART on hepatitis C, hepatitis G, and TT virus in multiply coinfected HIV-positive patients with haemophilia

In multiply coinfected human immunodeficiency virus (HIV)-positive patients, we investigated the effects of high-activity antiretroviral therapy (HAART) using HIV protease inhibitors on three other viruses: hepatitis C virus (HCV), hepatitis G virus (HGV), and TT virus (TTV). Viral concentrations were measured serially by polymerase chain reaction methods in five patients with quadruple infection (HIV, HCV, HGV, and TTV) and in two patients with triple infection (HIV, HCV, and HGV) before and during HAART. In addition, CD4+ cell counts and serum alanine aminotransferase (ALT) levels were measured serially. Generally we observed no difference in serum HCV RNA, HGV RNA, or TTV DNA concentrations between samples obtained before and after initiation of HAART, whereas HIV RNA concentration decreased and CD4 counts increased in most patients. However, two patients had markedly decreased concentrations of HCV RNA and HGV RNA, respectively, more than 12 months after beginning HAART. Normalization of serum ALT levels was observed in a patient with decline of HCV RNA concentrations. No interactions were observed among these four viruses. HAART had no apparent direct effects on HCV, HGV, or TTV. Further studies will be required to elucidate whether the restoration of immune status through suppression of HIV replication by HAART may affect HCV or HGV RNA concentrations.     

Hepatitis viruses (other than hepatitis B and C viruses) as causes of hepatocellular carcinoma: an update

Chronic hepatitis B and C virus infections are universally accepted as causes of hepatocellular carcinoma in humans. Hepatitis A and E viruses cause only acute self‐limiting infections of the liver. Of the remaining hepatitis viruses ‐ Delta hepatitis, hepatitis G (GB‐C), TT and SEN ‐ all have at some time been incriminated as causes of hepatocellular carcinoma. Delta hepatitis virus requires helper functions from hepatitis B virus to become invasive. Chronic Delta/hepatitis B viral co‐infection runs a more severe course than that resulting from chronic hepatitis B virus infection alone, with progression to cirrhosis being more likely and more rapid. A substantial majority of the early studies did not find an increased incidence of hepatocellular carcinoma in co‐infected individuals. But more recently, an increased incidence of the tumour has been recorded more often than no increase. Further studies are needed to draw a firm conclusion with regard to the hepatocarcinogenic effect of dual Delta/hepatitis B virus co‐infection. With one exception, no published study (of 13) has incriminated chronic infection with hepatitis G virus as a cause of hepatocellular carcinoma. The dissenting study, published in 1999, was the only one performed in the United States. Fewer studies of the hepatocarcinogenic effect of TT virus have been performed. Apart from one study, published in 1999, no convincing evidence is available that supports a causal role for TT virus in hepatocarcinogenesis. The exception was in Japanese patients with high hepatitis C viral loads but independent of chronic hepatitis C virus infection. No evidence has been produced to indicate that SEN virus causes hepatocellular carcinoma.