The severe acute respiratory syndrome coronavirus (SARS-CoV) is the major causative agent for the worldwide outbreak of SARS in 2003. The mechanism by which SARS-CoV causes atypical pneumonia remains unclear. The nuclear factor kappa B (NF-κB) is a key transcription factor that activates numerous genes involved in cellular immune response and inflammation. Many studies have shown that NF-κB plays an important role in the pathogenesis of lung diseases. In this study, we investigated the possible regulatory interaction between the SARS-CoV nucleocapsid (N) protein and NF-κB by luciferase activity assay. Our results showed that the SARS-CoV N protein can significantly activate NF-κB only in Vero E6 cells, which are susceptible to SARS-CoV infection, but not in Vero or HeLa cells. This suggests that NF-κB activation is cell-specific. Furthermore, NF-κB activation in Vero E6 cells expressing the N protein is dosedependent. Further experiments showed that there is more than one function domain in the N protein responsible for NF-κB activation. Our data indicated the possible role of the N protein in the pathogenesis of SARS.

T4病毒科由一类单股正链RNA病毒组成，分为松天蛾B样病毒属和松天蛾 样病毒属。这2个属的病毒具有不同的基因组结构，8样病毒含单组分基因组，其结构蛋白由一亚基因组RNA表达；而 样病毒含双组分基因组，2个RNA分子分别编码复制酶蛋白和结构蛋白。在T4病毒基因组RNA3 端有类似tRNA的二级结构。样病毒壳蛋白的氨基酸序列一致性高达66%～86&，而G样病毒壳蛋白的氨基酸同源性则要低得多。在昆虫细胞中表达壳蛋白基因时都能形成病毒类似粒子。该文还介绍了T4病毒复制机理以及T4病毒与其他病毒的进化关系。

为了表达马尾松毛虫质型多角体病毒（DpCPV）多角体蛋白基因（s10片段）并探讨多角体蛋白在真核细胞中的定位，从DpCPV中分离出S10， pET-28a载体连接成重组表达质粒pET28-SIO；将sl0克隆到杆状病毒转座载体pFASTBAC HTb中，依次筛选出重组转座质粒pFASTBAC S10，重组穿梭质粒Bacmid S10，重组杆状病毒Ac Sl0。多角体蛋自基 表达后，刚SDS. PAGE、Western. blot和免疫荧光技术对表达产物进行了检测。结果表明：Sl0原核表达质粒、重组杆状病毒成功获得；在昆虫细胞中表达的质型多角体蛋白主要定位于细胞质，同时有少量产物定位f细胞核。

用Trizol从纯化的茶尺蠖Ectropis oblique小RNA病毒（EoPV）中提取病毒基因组RNA，逆转录后加poly（dT），然后进行两步PCR扩增基因组5'端。克隆测序后，对其5 端非编码区的核苷酸序列进行分析，发现具有哺乳动物小RNA病毒的5'端非编码区的一些特征：A/T含量丰富、起始密码子上游AUG和小顺反子多。利用mfold预测了EoPV5'端非编码区的二级结构，存在4个茎环结构，有哺乳动物内部核糖体进入位点（IRES）的保守区域，即含保守基序GNRA的茎环A和A/C丰富的环B及多聚嘧啶区域。据此推测EoPV基因组翻译采用IRES起始机制。

The non-structural (NS) proteins of parvoviruses are involved in essential steps of the viral life cycle. Various biochemical functions, such as ATP binding, ATPase, site-specific DNA binding and nicking, and helicase activities, have been assigned to the protein NS1. Compared with the non-structural proteins of the vertebrate parvoviruses, the NS proteins of the Densovirinae have not been well characterized. Here, we describe the biochemical properties of NS1 of Periplaneta fuliginosa densovirus (PfDNV). We have expressed and purified NS1 using a baculovirus system and analyzed its enzymatic activity. The purified recombinant NS1 protein possesses ATPaseand ATP-or dATP-dependent helicase activity requiring either Mg2+ or Mn2+ as a cofactor. The ATPase activity of NS1 can be efficiently stimulated by single-stranded DNA. The ATPase coupled helicase activity was detected on blunt-ended double-stranded oligonucleotide substrate. Using South-Western and Dot-spot assays, we identified a DNA fragment that is recognized specifically by the recombinant NS1 protein. The fragment consists of (CAC)4 and is located on the hairpin region of the terminal palindrome. The domain for DNA binding was defined to the amino-terminal region (amino acids 1-250). In addition, we found that NS1 can form oligomeric complexes in vivo and in vitro. Mutagenesis analysis showed that ATP binding is necessary for oligomerization. Based on these results, it seems that PfDNV NS1, a multifunctional protein, plays an important role in viral DNA replication comparable to those of vertebrate parvovirus initiator proteins.