We examined the intracellular localization of NS5 protein of Dendrolimus punctatus cytoplasmic polyhedrosis virus (DpCPV) by expressing NS5-GFP fusion protein and proteins from deletion mutants of NS5 in baculovirus recombinant infected insect Spodoptera frugiperda (Sf-9) cells. It was found that the NS5 protein was present at the plasma membrane of the cells, and that the N-terminal portion of the protein played a key role in the localization. A transmembrane region was identified to be present in the N-terminal portion of the protein, and the detailed transmembrane domain (SQIHMVWVKSGLVFF, 57-71aa) of N-terminal portion of NS5 was further determined, which was accorded with the predicted results, these findings suggested that NS5 might have an important function in viral life cycle.

In this study, Dendrolimus punctatus tetravirus (DpTV) has been identified as a new member of the genus Omegatetravirus of the family Tetraviridae that may be related serologically to Nudaurelia capensis v virus (NvV). DpTV particles are isometric, with a diameter of about 40nm and a buoyant density of 1?281 g cm3 in CsCl. The virus has two capsid proteins (of 62 500 and 6800 Da) and two single-stranded RNA molecules (RNA1 and RNA2), which are 5492 and 2490 nt long, respectively. RNA1 has a large open reading frame (ORF) encoding a polypeptide of 180 kDa; RNA2 contains two partially overlapping ORFs encoding polypeptides of 17 and 70 kDa. The 180 kDa protein, which contains consensus motifs of a putative methyltransferase, helicase and RNA-dependent RNA polymerase, shows significant similarity to those of other tetraviruses. The 17 kDa protein is a PEST (Pro/Glu/Ser/Thr) protein of unknown function. The 70 kDa protein is the coat protein precursor and is predicted to be cleaved at an Asn-Phe site located after residue 570. The 70 kDa protein shows 86 and 66% identity to its homologues in NvV and Helicoverpa armigera stunt virus, respectively. Secondary-structure analysis revealed that the RNAs of DpTV have tRNA-like structures at their 39 termini.

The nucleotide sequence of a novel icosahedral DNA virus infecting Dendrolimus punctatus has been determined. The genome is 5039 nt long and includes inverted terminal repeats of 200 nt containing 131 nt long J-shaped terminal hairpins. The 'plus' strand of the genome contains three large open reading frames (ORFs), the left and the mid-ORFs (within the left ORF) in the left-half encoding the non-structural proteins and the right ORF in the right-half encoding viral capsid proteins. NS1 protein contains conserved replication initiation and DNA-dependent ATPase/helicase domains. VP1 protein contains a conserved PGY and phospholipase A2 motifs and shows high identities with VPs of Casphalia extranea densovirus and Bombyx mori densovirus-1 belonging to the genus Iteravirus. Phylogenetic analysis also revealed that this virus is most closely related to Casphalia extranea densovirus and Bombyx mori densovirus-1. Consequently, this virus was considered as a new third member of the genus Iteravirus of the subfamily Densovirinae, and designated Dendrolimus punctatus densovirus.

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。

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。