庚型肝炎病毒包膜糖蛋白E2基因在昆虫细胞中的表达

用ＰＣＲ扩增出ＨＧＶＥ２全基因,克隆进杆状病毒表达载体ｐＦＡＳＴＢＡＣＨＴａ中,构建成重组转座载体ｐＦＡＳＴＢＡＣＥ２,转化ＤＨ１０ＢＡＣ大肠杆菌感受态细胞,筛选阳性菌落,抽提大分子质粒ＤＮＡ,获得含ＨＧＶＥ２基因的重组杆状病毒穿梭载体,转染昆虫草地夜蛾Ｓｆ９细胞,出现细胞病变后,收集含有重组病毒颗粒的培养上清,重新感染草地夜蛾Ｓｆ９单层细胞及甜菜夜蛾幼虫,分别收集Ｓｆ９细胞和甜菜夜蛾幼虫体内的血淋巴细胞,进行１２％ＳＤＳ聚丙烯酰胺凝胶电泳,可见表达的融合蛋白带,经亲和层析进行蛋白纯化,用ＥＬＩＳＡ方法检测各类血清标本,初步研究ＨＧＶＥ２糖蛋白的抗原性     

Mechanisms,function and clinical applications of DNp73

p73, has two distinct promoters, which allow the formation of two protein isoforms: full-length transactivating (TA) p73 and an N-terminally truncated p73 species (referred to as DNp73) that lacks the N-terminal transactivating domain. Although the exact cellular function of DNp73 is unclear, the high expression levels of the genes have been observed in a variety of human cancers and cancer cell lines and have been connected to pro-tumor activities. Hence the aim of this review is to summarize DNp73 expression status in cancer in the current literature. Furthermore, we also focused on recent findings of DNp73 related to the biological functions from apoptosis, chemosensitivity, radiosensitibity, differentiation, development, etc. Thus this review highlights the significance of DNp73 as a marker for disease severity in patients and as target for cancer therapy.     

Predicting G-protein coupled receptors-G-protein coupling specificity based on autocross-covariance transform

Determining G-protein coupled receptors (GPCRs) coupling specificity is very important for further understanding the functions of receptors. A successful method in this area will benefit both basic research and drug discovery practice. Previously published methods rely on the transmembrane topology prediction at training step, even at prediction step. However, the transmembrane topology predicted by even the best algorithm is not of high accuracy. In this study, we developed a new method, autocross-covariance (ACC) transform based support vector machine (SVM), to predict coupling specificity between GPCRs and G-proteins. The primary amino acid sequences are translated into vectors based on the principal physicochemical properties of the amino acids and the data are transformed into a uniform matrix by applying ACC transform. SVMs for nonpromiscuous coupled GPCRs and promiscuous coupled GPCRs were trained and validated by jackknife test and the results thus obtained are very promising. All classifiers were also evaluated by the test datasets with good performance. Besides the high prediction accuracy, the most important feature of this method is that it does not require any transmembrane topology prediction at either training or prediction step but only the primary sequences of proteins. The results indicate that this relatively simple method is applicable. Academic users can freely download the prediction program at http://www.scucic.net/group/database/Service.asp.     

Hepatitis C virus protects human B lymphocytes from Fas-mediated apoptosis via E2-CD81 engagement

HCV infection is often associated with B-cell regulatory control disturbance and delayed appearance of neutralizing antibodies. CD81 is a cellular receptor for HCV and can bind to HCV envelope protein 2 (E2). CD81 also participates to form a B cell costimulatory complex. To investigate whether HCV influences B cell activation and immune function through E2 -CD81 engagement, here, human Burkitt's lymphoma cell line Raji cells and primary human B lymphocytes (PHB) were treated with HCV E2 protein and cell culture produced HCV particles (HCVcc), and then the related cell phenotypes were assayed. The results showed that both E2 and HCVcc triggered phosphorylation of IκBα, enhanced the expression of anti-apoptosis Bcl-2 family proteins, and protected Raji cells and PHB cells from Fas-mediated death. In addition, both E2 protein and HCVcc increased the expression of costimulatory molecules CD80, CD86 and CD81 itself, and decreased the expression of complement receptor CD21. The effects were dependent on E2-CD81 interaction on the cell surface, since CD81-silenced Raji cells did not respond to both treatments; and an E2 mutant that lose the CD81 binding activity, could not trigger the responses of both Raji cells and PHB cells. The effects were not associated with HCV replication in cells, for HCV pseudoparticle (HCVpp) and HCVcc failed to infect Raji cells. Hence, E2-CD81 engagement may contribute to HCV-associated B cell lymphoproliferative disorders and insufficient neutralizing antibody production.     

SARS相关冠状病毒及其基因组

正在全球部分地区流行的严重急性呼吸综合征(SARS),由于其传染性强、危害性大而引起了广泛关注。各国实验室密切协作,在数月时间内分离出了SARS冠状病毒(SARSCoV),测定了病毒基因组序列,并在猴体内初步再现出SARSCoV所致肺部疾病与人相似,这些工作为遏制SARS的蔓延发挥了重要作用。现就SARSCoV的鉴定、基因组及其产物的结构与功能做一综述。     

Synthesis and Biological Activities of Novel (Z)-/(E)-Anisaldehyde-Based Oxime Ester Compounds

In search of novel natural product-based bioactive molecules, twenty (ten pairs) novel (Z)-/(E)-anisaldehyde-based oxime ester compounds were designed and synthesized by using anisaldehyde as starting material. Structural characterization of the target compounds was carried out by NMR, FT-IR, ESI-MS, and elemental analysis. Their herbicidal and antifungal activities were preliminarily tested. As a result, at 50 μg/mL, compound (E)- 5b exhibited excellent to good inhibition rates of 92.3 %, 79.2 %, and 73.9 %, against Rhizoctonia solani, Fusarium oxysporum f. sp. cucumerinum, and Bipolaris maydis, respectively, better than or comparable to that of the positive control chlorothalonil. In addition, at 100 μg/mL, compounds (E)- 5b , (E)- 5f , (Z)- 5f and (E)- 5d exhibited excellent to good inhibition rates of 85.8 %, 82.9 %, 78.6 % and 64.2 %, respectively, against the root-growth of rape (B. campestris), much better than that of the positive control flumioxazin. The bioassay result also showed that the synthesized compounds had obvious differences in antifungal and herbicidal activities between (Z)- and (E)-isomers. Preliminary structure–activity relationship was also discussed by theoretical calculation.     

Three Different Functional Microdomains in the Hepatitis C Virus Hypervariable Region 1 (HVR1) Mediate Entry and Immune Evasion

High genetic heterogeneity is an important characteristic of hepatitis C virus (HCV) that contributes to its ability to establish persistent infection. The hypervariable region 1 (HVR1) that includes the first 27 amino acid residues of the E2 envelope glycoprotein is the most variable region within the HCV polyprotein. HVR1 plays a major role in both HCV cell entry and immune evasion, but the respective contribution of specific amino acid residues is still unclear. Our mutagenesis analyses of HCV pseudoparticles and cell culture-derived HCV using the H77 isolate indicate that five residues at positions 14, 15, and 25–27 mediate binding of the E2 protein to the scavenger receptor class B, type I receptor, and any residue herein is indispensable for HCV cell entry. The region spanning positions 16–24 contains the sole neutralizing epitope and is dispensable for HCV entry, but it is involved in heparan binding. More importantly, this region is necessary for the enhancement of HCV entry by high density lipoprotein and interferes with virus neutralization by E2-neutralizing antibodies. Residues at positions 1–13 are also dispensable for HCV entry, but they can affect HCV infectivity by modulating binding of the envelope protein to scavenger receptor class B, type I. Mutations occurring at this site may confer resistance to HVR1 antibodies. These findings further our understanding about the mechanisms of HCV cell entry and the significance of HVR1 variation in HCV immune evasion. They have major implications for the development of HCV entry inhibitors and prophylactic vaccines.     

我国丙型肝炎病毒囊膜蛋白E2高变区1的序列特征

对２３例国内献血员、血透析及肝炎病人血清用反转录巢式ＰＣＲ技术扩增了ＨＣＶＲＮＡ囊膜蛋白２基因的ｃＤＮＡ片段,并进行了序列测定。结果表明２３例病人ＨＣＶＥ２／ＮＳ１Ｎ末端的核苷酸及氨基酸序列呈现多样性,高变区１（ＨＶＲ１）位于核苷酸第１４５９～１５５９位,氨基酸第３８４～４１０位;我国ＨＣＶ株ＨＶＲ１２７个氨基酸中有１５个位置氨基酸相对稳定,氨基酸组成与分布均与Ｓｅｋｉｙａ报道的１６６个ＨＣＶ株的不同。结果提示,研究我国ＨＣＶ株ＨＶＲ１的序列特征有助于ＨＣＶ的流行病学研究,对研制适用于我国的抗体诊断试剂盒及进行疫苗研究均有重要的意义。     

新型冠状病毒基因组结构与蛋白功能

2019年12月以来,武汉市暴发新型冠状病毒肺炎(coronavirus disease 2019,COVID-19)疫情并迅速蔓延全国,2020年1月30日被世界卫生组织(World Health Organization,WHO)列为“国际关注的突发公共卫生事件”(public health emergency of international concern,PHEIC)。核酸序列分析证明COVID-19由新型冠状病毒(2019 novel coronavirus,2019-nCoV)引起。2019-nCoV为正链单链RNA病毒,基因组长约30 kb,两端为非编码区,中间为非结构蛋白编码区和结构蛋白编码区。非结构蛋白编码区主要包括开放读码框架(open reading frame,ORF)1a和ORF1b基因,编码16个非结构蛋白(non-structural proteins,NSP),即NSP1～16。结构蛋白编码区主要编码刺突(spike,S)蛋白、包膜(envelope,E)蛋白、膜(membrane,M)蛋白和核衣壳(nucleocapsid,N)蛋白。深入了解2019-nCoV基因组的结构和蛋白功能,将为2019-nCoV相关的病毒溯源、复制增殖、致病免疫、药物与疫苗研发以及当前疫情的防控提供有力的支撑。