Liao Qinfeng, Zheng Lisha, Yuan Yuan, Shi Jiajian, Zhang Dabing
Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China; Department of Animal Science and Technology, Chongqing Three Gorges Vocational College, Chongqing, China.
Key Laboratory of Animal Epidemiology and Zoonosis of Ministry of Agriculture, College of Veterinary Medicine, China Agricultural University, Beijing, China.
Vet Microbiol. 2014 Aug 6;172(1-2):78-91. doi: 10.1016/j.vetmic.2014.05.002. Epub 2014 May 13.
A novel picornavirus was detected from Pekin ducks (Anas platyrhynchos domestica) and completely sequenced. The virus was most closely related to megriviruses, with amino acid identities of 32-68%, 35-45%, 51-57%, 41-50%, and 61-63% in the P1, P2, P3, polyprotein, and 2C and 3CD regions, respectively. The virus was thus identified as an additional species in the genus Megrivirus and named Duck megrivirus (DMV). Sequence analyses indicated that the DMV genome possessed a megrivirus-like organization and also exhibited several unique features. The polyadenylated genome comprised 9700nt, one of the largest among known picornaviruses. A notable feature was the 2A region, which had an association of two distinct, function-unknown 2As (2A1 and 2A2) and a parechovirus-like 2A3. The 5' untranslated region (UTR) contained a variant type IVB internal ribosome entry site (IRES), which possessed a long helix III4 ending with the "8"-like 20-nt-long conserved structure at the top of domain III. The secondary structure model of inferred domain III of DMV-like IRES was also conserved in quail picornavirus, pigeon picornavirus B, and megriviruses. Domain II in DMV contained the conserved internal and apical loops previously identified in groups A and C of hepacivirus/pestivirus like IRESs. Moreover, DMV was closely related to different megriviruses in different genomic regions. These findings suggest that recombination events involving exchange of coding and noncoding regions may have occurred. DMV was detected in 28 of 117 (23.9%) ducks from four provinces in China, suggesting a high prevalence of DMV in duck populations.
从北京鸭（Anas platyrhynchos domestica）中检测到一种新型小RNA病毒，并对其进行了全序列测定。该病毒与巨河病毒关系最为密切，在P1、P2、P3、多聚蛋白以及2C和3CD区域的氨基酸同源性分别为32 - 68%、35 - 45%、51 - 57%、41 - 50%和61 - 63%。因此，该病毒被鉴定为巨河病毒属中的一个新种，命名为鸭巨河病毒（DMV）。序列分析表明，DMV基因组具有类似巨河病毒的结构组织，同时也表现出一些独特特征。该多聚腺苷酸化基因组由9700个核苷酸组成，是已知小RNA病毒中最大的之一。一个显著特征是2A区域，它包含两个功能未知的不同2A（2A1和2A2）以及一个类帕里病毒的2A3。5'非翻译区（UTR）包含一个IVB型可变内部核糖体进入位点（IRES），其具有一个长的螺旋III4，在结构域III顶部以“8”样的20个核苷酸长的保守结构结尾。DMV样IRES推断的结构域III的二级结构模型在鹌鹑小RNA病毒、鸽小RNA病毒B和巨河病毒中也保守。DMV的结构域II包含先前在丙型肝炎病毒/瘟病毒样IRES的A组和C组中鉴定出的保守内部环和顶端环。此外，DMV在不同基因组区域与不同的巨河病毒密切相关。这些发现表明可能发生了涉及编码区和非编码区交换的重组事件。在中国四个省份的117只鸭中有28只（23.9%）检测到DMV，表明鸭群中DMV的流行率较高。
