中国人丙型肝炎病毒基因组3‘端非编码区的研究

目的 分析中国丙型肝炎病人ＨＣＶ基因组３‘端非编码区,以促进对ＨＣＶ基因组复制机制的研究。方法 采用两种方法,从上海地区感染ＨＣＶ的病人血清中,扩增获得ＨＣＶ基因组３’端非编码区：一是用套式ＰＣＲ直接的增,二是先分别ＨＣＶ３‘ＮＣＲ的前半部分和后半部分,再将两片段进行融合ＰＣＲ。ＰＣＲ产物进行测序后作同源性分析。     

丙型肝炎血症水平与慢性丙型肝炎患者的关系

为了研究丙型肝炎病毒（ＨＣＶ）血症水平与慢性丙型肝炎患者临床特征的关系,我们对２４例慢性丙肝患者血清ＨＣＶＲＮＡ水平进行了定量检测。２４例慢性丙型肝炎患者,男１６例,女８例,平均年龄４０－５±５－８岁,诊断符合１９９５年５月北京第五次全国传染病寄生虫病学术会议讨论修订的病毒性肝炎防治方案。血清标本来自患者应用抗病毒药物前的空腹静脉血。逆转录引物选自ＨＣＶＲＮＡ的５′非编码区,为５′ＧＡＣＣＣＡＡＣＡＣＴＡＣＴＣＧＧＣＴＡ３′,非对称ＰＣＲ扩增引物来自延长逆转录引物的ｃＤＮＡ产物内的非对称扩增…     

中国南京庚型肝炎病毒部分基因的克隆及cDNA序列分析

采用反转录聚合酶链反应（ＲＴＰＣＲ）从南京地区某输血后丙型肝炎患者血清中克隆出庚型肝炎病毒（ＨＧＶ）非结构区部分基因。序列分析结果表明：该序列与国外发表的庚型肝炎病毒ＨＧＵ４４４０２，ＨＧＵ４５９６６，ＨＧＵ３６３８０（ＧＢＶＣ）对应位置核苷酸序列同源性分别为８９０９％，９２１２％，８７２７％，与已报道的ＨＧＶ河北株序列同源性为９３９４％。对４０份输血后丙型肝炎血清和３０份非甲非乙非丙非丁非戊型肝炎血清进行了检测，ＨＧＶＲＮＡ阳性率分别为１０００％和６６７％。     

深圳地区不同人群庚型肝炎病毒感染的分子流行病…

在庚型肝炎病毒（ＨＧＶ）基因５’端非编码区（５’－ＵＴＲ）设计两对套式引物，建立检测ＨＧＶＲＮＡ的逆转录－巢式聚合酶链反应（ＲＴ－ｎｅｓｔｅｄＰＣＲ）。对深圳地区１０６例职业献血员，１６８例肝炎病人及８０例静脉毒瘾者进行ＨＧＶＲＮＡ的检测，阳性率分别为８．５％，７．７％与４６．３％前两者与后者相比较差异均有显著性意义（Ｐ〈０．０１）。６１例慢性乙型肝炎与３３例慢性丙型肝炎病人ＨＧＶＲＮＡ阳性率分别     

定量逆转录PCR检测丙肝病毒RNA

在反应体系中加入定量的突变型ＨＣＶ－ＲＮＡ模板进行竞争逆转录ＰＣＲ（ＣＲＴ－ＰＣＲ）可以定量测定标本中ＨＣＶ－ＲＮＡ基因组拷贝数。ＣＲＴ－ＰＣＲ研究表明，随肝病进展，患者血清ＨＣＶ－ＲＮＡ复制水平持续增高；血清病毒含量高者对干扰素治疗反应差。     

HCV5′NCR片段调控荧光素酶表达质粒的构建及其在H …

目的 构建ＨＣＶ５′ＮＣＲ片段调控荧光素酶表达质粒,并在ＨｅｐＧ２细胞中表达。方法 ＰＣＲ扩增,获得中国人ＨＣＶ基因组５′非编码区（ｎｏｎｃｏｄｉｎｇ ｒｅｇｉｏｎ,ＮＣＲ）完整序列与Ｃ区部分序列的目的基因片段（５′ＮＣＲ－Ｃ片段）。将此片段插入ｐＧＬ３荧光素酶报告载体蝗荧光素酶基因起始密码上游,构建受５′ＮＣＲ片段调控的荧光素酶表达质粒。应用脂质体介导基因转染技术将８个质粒转染ＨｅｐＧ２肝癌细胞     

多重引物聚合酶链反应扩增丙型肝炎病毒基因及基 …

利用聚合酶链反应（ＰＣＲ）技术对丙型肝炎病毒（ＨＣＶ）的５’－非编码区（５’－ＮＣＲ）、Ｃ及ＮＳ４基因区的３对引物分别及同时扩增，检测８０例抗－ＨＣＶ阳性患者的血清ＨＣＶ ＲＮＡ，并进行了ＨＣＶ基因分型研究。各不同引物所介导的ＰＣＲ检出ＨＣＶ ＲＮＡ的结果为：５’－ＮＣＲ基因区６０％（４８／８０），Ｃ基因区３７％（３０／８０），ＮＳ４基因区３０％（２４／８０）。以上３对引物同时扩增仅４２％（３４／     

用直接法原位聚合酶链反应检测肝组织中HCV RNA

用直接法原位聚合酶链反应检测肝组织中ＨＣＶＲＮＡ杨志国许家璋徐俊杰乐美兆苏长青一、材料与方法１材料：取血清ＨＣＶＲＮＡ及／或抗ＨＣＶＩｇＧ阳性的丙型肝炎肝脏活检标本，经１０％福马林固定，石蜡包埋。２试剂：ＨＣＶＲＮＡ引物选自５′端非编码区，限定...     

从人外周血淋巴细胞扩增抗体可变区基因的3种方法

介绍了从人外周血淋巴细胞（ＰＢＬ）以传统方法提取总ＲＮＡ再行反转录ＰＣＲ（ＲＴ－ＰＣＲ）、以Ｔｒｉｚｏｌ Ｒｅａｇｅｎｔ提取ＲＮＡ再行ＲＴ－ＰＣＲ以及细胞内直接ＲＴ－ＰＣＲ等３种方法扩增人抗体可变区（Ｖ区）基因的方法并作了比较。３种方法均扩增出了人抗体ＶＨ、Ｖκ、Ｖλ基因，从方法的简便及结果的可靠等方面综合考虑，作者推荐以Ｔｒｉｚｏｌ Ｒｅａｇｅｎｔ提取ＲＮＡ再行ＲＴ－ＰＣＲ扩增的方法。     

乌鲁木齐市部分高危人群庚型肝炎病毒感染现状及5′ UTR区基因序列分析

新疆地处我国西部边陲 ,存在着各型肝炎散发流行的危险因素 ,庚型肝炎病毒在乌鲁木齐市的流行现状尚未见报道。在新疆医科大学第一附院收集了2 67份各类人群的血清 ,用酶标法检测血清中庚型肝炎病毒抗体 (抗 ＨＧＶ) ,再以庚型肝炎病毒ＮＳ3区为引物运用ＲＴ ＰＣＲ法对抗 ＨＧＶ(阳性 )血清进行庚型肝炎病毒核酸 (ＨＧＶＲＮＡ)的扩增检测 ,阳性扩增产物为 83ｂｐ。最后 ,选择该病毒 5′非编码区为引物对第一次ＲＴ ＰＣＲ扩增ＨＧＶＲＮＡ(阳性 )血清 ,再次进行163.ｃｏｍ)ＲＴ ＰＣＲ扩增 ,阳性扩增产物为 1 90ｂｐ ,对第二次扩增ＨＧＶ…     

Interaction of poly(rC)-binding protein 2 with the 5'-terminal stem loop of the hepatitis C-virus genome

The 5' noncoding region (NCR) of hepatitis C virus (HCV) contains an internal ribosome entry site for translation initiation. Cellular proteins (e.g. La, polypyrimidine tract-binding protein, and p25) that interact with HCV 5' NCR have been implicated in facilitating efficient internal initiation. The 5' NCR may also contain RNA structures and specific RNA sequences that interact with cellular proteins to promote RNA replication. UV crosslinking experiments revealed a 43-kDa cellular protein (p43) also interacts with the HCV 5' NCR. Further UV crosslinking experiments with deletion mutants of HCV 5' NCR demonstrated that p43 bound specifically to the 5'-terminal stem-loop of the HCV 5' NCR. Achromobactor proteinase I digests, competition experiments, and immunoprecipitation confirmed that p43 was identical to human poly(rC)-binding protein 2 (PCBP2). We prepared a PCBP2-immunodepleted rabbit reticulocyte lysate with an anti-PCBP2 antibody. Translation activity promoted by the HCV internal ribosome-entry site was the same in PCBP2-depleted lysates as in mock-depleted lysates. In conclusion, PCBP2 specifically interacted with the 5' terminus of HCV genome but had no effect on HCV translation. We speculate that PCBP2's interaction with HCV 5' NCR may be involved in the replication-initiation complex of HCV.     

Selection of genetic variants of the 5' noncoding region of hepatitis C virus occurs only in patients responding to interferon alpha therapy.

Interferon alpha (IFN alpha) can suppress the replication of hepatitis C virus (HCV) in chronically infected patients. However, HCV persists in a significant number of patients despite the normalization of alanine transaminase (ALT) during IFN alpha therapy. In this study, HCV variants in patients under IFN alpha therapy were characterized to examine their role in viral persistence during the therapy. Sixteen patients selected for this study were infected with HCV genotype 1b and remained HCV RNA positive for at least 1 month after onset of therapy. Nine patients responded to the therapy in terms of normalization of ALT (responders), whereas seven patients did not show a significant decrease of ALT level (nonresponders). To examine HCV populations in these patients, the HCV 5' noncoding region (5' NCR) was analyzed by polymerase chain reaction amplification and sequencing. Newly emerging variants of the HCV 5' NCR replaced predominant variants present prior to IFN alpha therapy in six of nine responders. Most predominant HCV variants during IFN alpha therapy carried a nucleotide substitution G to A at nt 231 within the 5' NCR. An analysis of the HCV quasispecies population in one responder revealed that a preexisting variant became predominant under IFN alpha therapy. These results emphasized the importance of the genetic heterogeneity of the HCV genome for viral resistance to IFN alpha. Five of seven HCV isolates from nonresponders were identical to those found in responders with regard to the nucleotide sequence of the 5' NCR. However, no selection of variants of the HCV 5' NCR occurred in nonresponders during the course of therapy. We conclude that IFN alpha treatment leads to the selection of variants of the HCV 5' NCR only in responders and may act differently in nonresponders. Our results suggest that the HCV 5' NCR may be a target of anti-HCV actions of IFN alpha.     

Improved detection of rhinoviruses by nucleic acid sequence-based amplification after nucleotide sequence determination of the 5' noncoding regions of additional rhinovirus strains

The isothermal nucleic acid sequence-based amplification (NASBA) system was applied for the detection of rhinoviruses using primers targeted at the 5' noncoding region (5' NCR) of the viral genome. The nucleotide sequence of the 5' NCRs of 34 rhinovirus isolates was determined to map the most conserved regions and design more appropriate primers and probes. The assay amplified RNA extracted from 30 rhinovirus reference strains and 88 rhinovirus isolates, it did not amplify RNA from 49 enterovirus isolates and other respiratory viruses. The assay allows one to discriminate between group A and B rhinoviruses. Sensitivities for the detection of group B and group A rhinoviruses was 20 and 200 50% tissue culture infective doses, respectively.     

Detection of hepatitis C viraemia in Caucasian patients with hepatocellular carcinoma.

Potential risk factors for the development of hepatocellular carcinoma were analysed in 40 Caucasian patients with this malignancy. A higher proportion (14 of 40; 35%) had evidence of hepatitis C virus (HCV) infection than had evidence of either hepatitis B virus (HBV) carriage (17.5%) or alcohol abuse (30%). In all 14 patients whose sera were reactive by HCV ELISA (Ortho second generation test), the presence of antibodies to HCV were confirmed by recombinant immunoblot assay (Ortho RIBA-2). Furthermore, two independent laboratories detected HCV-RNA in 10 of the 14 (71%) anti-HCV positive sera. Two additional sera were shown to contain HCV-RNA when reanalysed by a modified PCR using oligonucleotide primers designed to amplify a shorter fragment of the 5' noncoding region of the genome. Seven of the anti-HCV positive patients also had evidence of prior HBV infection and 2 admitted to alcohol abuse. HCV infection was the only identifiable risk factor in 6 patients. These data confirm the association between HCV infection and hepatocellular carcinoma and suggest that persistent viral replication accompanies tumour development in the majority of patients whose serum contains anti-HCV.     

Detection and genotyping of GBV-C/HGV variants in China

We detected GBV-C/HGV sequences in the sera from 64 out of a total of 324 subjects in the south of China. In agreement with findings of others, we noted an especially high rate of infection among intravenous drug addicts and patients with chronic hepatitis C virus infection. The detection was achieved by nested PCR to amplify the 5' noncoding region (5'NCR) of the viral genome. Sequence analysis of the resulting 234 bp product revealed a total of 26 different sequences of which 25 were found to belong to the genotype G3, which is the most prevalent genotypes among Asian isolates, and one belonged to genotype G1, common among African isolates. The sequence divergence between the genotypes was largely clustered in a short variable region (V2) within the 5'NCR, and we showed that genotyping may be achieved equally well by analysis of this variable region as by the more detail analysis of the entire 5'NCR or of the entire viral genome.     

丙型肝炎病毒阳性血清体外感染人肝细胞的研究

目的 研究丙型肝炎病毒(HCV)抗体(Ab)阴性,HCV-RNA阳性血清建立体外感染肝细胞模型.方法 HCV Ab阴性,HCV-RNA阳性的窗口期血清与人肝细胞共同培养,用反转录-聚合酶链反应(RT-PCR)、免疫荧光染色、Western blot、共聚焦显微镜和透射电镜等方法检测细胞内HCV核酸复制、蛋白质表达及超微结构改变.结果 细胞与病毒共同培养7～45 d,细胞内和/或培养上清中可间断检出HCV正、负链RNA;细胞浆内有HCV 核心和NS3抗原的表达;细胞超微结构有改变,并于感染后第24天时观察到类似病毒样颗粒.结论 窗口期血清中的HCV能在人肝细胞7701中复制一段时间.     

A tymovirus with an atypical 3′-UTR illuminates the possibilities for 3′-UTR evolution

We report the complete genome sequence of Dulcamara mottle virus (DuMV), confirming its membership within the Tymovirus genus, which was previously based on physical and pathology evidence. The 5′-untranslated region (UTR) and coding region of DuMV RNA have the typical characteristics of tymoviral RNAs. In contrast, the 3′-UTR is the longest and most unusual yet reported for a tymovirus, possessing an internal poly(A) tract, lacking a 3′-tRNA-like structure (TLS) and terminating at the 3′-end with –UUC instead of the typical –CC(A). An expressible cDNA clone was constructed and shown to be capable of producing infectious DuMV genomic RNAs with –UUC 3′-termini. A chimeric Turnip yellow mosaic virus (TYMV) genome bearing the DuMV 3′-UTR in place of the normal TLS was constructed in order to investigate the ability of the TYMV replication proteins to amplify RNAs with –UUC instead of –CC(A) 3′-termini. The chimeric genome was shown to be capable of replication and systemic spread in plants, although amplification was very limited. These experiments suggest the way in which DuMV may have evolved from a typical tymovirus, and illuminate the ways in which viral 3′-UTRs in general can evolve.     

Role of La autoantigen and polypyrimidine tract-binding protein in HCV replication

To determine if the cellular factors La autoantigen (La) and polypyrimidine tract-binding protein (PTB) are required for hepatitis C virus (HCV) replication, we used siRNAs to silence these factors and then monitored their effect on HCV replication using quantitative RT-PCR. In addition, we determined the influence of PTB on the activity of the 3' noncoding region (NCR) of HCV and investigated its interaction with the components of the HCV replicase complex. We found that La is essential for efficient HCV replication while PTB appears to partially repress replication. PTB does, however, block the binding of HCV RNA-dependent RNA polymerase (RdRp, NS5B) to the 3'NCR. Indirect immunofluorescence microscopy showed co-localization of cytoplasmic PTB with the HCV RdRp in hepatoma cells (Huh-7) expressing HCV proteins, while in vitro translation of viral proteins from the HCV replicon revealed the interaction of PTB isoforms with NS5B polymerase and NS3.     

Cellular proteins bind to the poly(U) tract of the 3' untranslated region of hepatitis C virus RNA genome

UV cross-linking analyses were performed in an attempt to determine cellular protein-viral RNA interactions with the 3' untranslated region (3' UTR) of the hepatitis C virus RNA genome. Two cellular proteins, with estimated molecular masses of 58 kDa (p58) and 35 kDa (p35), respectively, were found to specifically bind to the 3' UTR. The p58 protein was determined to be the polypyrimidine tract-binding protein. In addition to binding to the conserved 98 nucleotides (nt) of the 3' UTR, p58 also binds to the poly(U) tract of the 3' UTR. The p35 protein was found to interact only with the poly(U) tract of the 3' UTR. These conclusions are supported by the following findings: (1) p58, and not p35, binds to the 3' end conserved 98 nt, (2) both p58 and p35 bind to a 3' UTR RNA with a deletion of the conserved 98 nt, (3) the 98-nt deletion mutant 3' UTR competed out both p58 and p35 binding, (4) a poly(U) homopolymer competed out both p58 and p35 binding, (5) a 3' UTR RNA with deletion of the poly(U) tract competed out only p58 binding but not p35 binding, and (6) an RNA containing the variable region of the 3' UTR with a deletion of both poly(U) tract and 98 nt failed to compete for binding of either p58 or p35. Interaction of these cellular proteins with the HCV 3' UTR is probably involved in regulation of translation and/or replication of the HCV RNA genome.