Phylogenetic analyses of the polyprotein coding sequences of serotype O foot-and-mouth disease viruses in East Africa: evidence for interserotypic recombination
Phylogenetic analyses of the polyprotein coding sequences of serotype O foot-and-mouth disease viruses in East Africa: evidence for interserotypic recombination
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DOI：
10.1186/1743-422x-7-199
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发表时间：
2010-08-23
期刊：
影响因子：
4.8
通讯作者：
Belsham, Graham J.
中科院分区：
文献类型：
--
作者：
Balinda, Sheila N.;Siegismund, Hans R.;Belsham, Graham J.
背景：口蹄疫(FMD)在东非流行，已报道的大多数暴发疫情都是由O型病毒引起的。在这项研究中，对来自肯尼亚和乌干达的O型口蹄疫病毒的多蛋白编码区进行了系统发育分析，以推断导致该血清型多样性产生和维持的进化关系和过程。在细胞培养中分离病毒后，从6个样本中提取口蹄疫病毒RNA，其中1个样本直接从口咽样本中提取。结果：VP1编码区的系统发育比较表明，东非新近分离的毒株属于EA-2拓扑型的一个谱系，而肯尼亚的K/52/1992株是EA-1拓扑型的代表株。除了K/52/1992有明显的进化关系外，前导蛋白(L)编码区、衣壳蛋白编码区和几乎整个编码区的进化关系都是单系进化的。K/52/1992与东非口蹄疫A型病毒(A21/Ken/1964和A23/Ken/1965)和O型病毒分离株(K/117/1999)的引导扫描分析表明，P2区可能来自A型毒株，而P3区似乎是来自A型和O型的嵌合体。结论：来自肯尼亚和乌干达的O型口蹄疫病毒的VP1编码区序列都代表了一个特定的东非血统(拓扑型EA-2)，一个可能的迹象表明，在最近的过去，几乎没有任何这种血清型的口蹄疫传入来自该地区以外的地区。此外，还获得了A型和O型口蹄疫病毒之间在非结构蛋白编码区进行血清型间重组的证据。除了使用VP1编码区进行特征分析外，还应进行涉及非结构蛋白编码区的分析，以确定形成口蹄疫病毒种群的进化过程。
Background: Foot-and-mouth disease (FMD) is endemic in East Africa with the majority of the reported outbreaks attributed to serotype O virus. In this study, phylogenetic analyses of the polyprotein coding region of serotype O FMD viruses from Kenya and Uganda has been undertaken to infer evolutionary relationships and processes responsible for the generation and maintenance of diversity within this serotype. FMD virus RNA was obtained from six samples following virus isolation in cell culture and in one case by direct extraction from an oropharyngeal sample. Following RT-PCR, the single long open reading frame, encoding the polyprotein, was sequenced.Results: Phylogenetic comparisons of the VP1 coding region showed that the recent East African viruses belong to one lineage within the EA-2 topotype while an older Kenyan strain, K/52/1992 is a representative of the topotype EA-1. Evolutionary relationships between the coding regions for the leader protease (L), the capsid region and almost the entire coding region are monophyletic except for the K/52/1992 which is distinct. Furthermore, phylogenetic relationships for the P2 and P3 regions suggest that the K/52/1992 is a probable recombinant between serotypes A and O. A bootscan analysis of K/52/1992 with East African FMD serotype A viruses (A21/KEN/1964 and A23/KEN/1965) and serotype O viral isolate (K/117/1999) revealed that the P2 region is probably derived from a serotype A strain while the P3 region appears to be a mosaic derived from both serotypes A and O.Conclusions: Sequences of the VP1 coding region from recent serotype O FMDVs from Kenya and Uganda are all representatives of a specific East African lineage (topotype EA-2), a probable indication that hardly any FMD introductions of this serotype have occurred from outside the region in the recent past. Furthermore, evidence for interserotypic recombination, within the non-structural protein coding regions, between FMDVs of serotypes A and O has been obtained. In addition to characterization using the VP1 coding region, analyses involving the nonstructural protein coding regions should be performed in order to identify evolutionary processes shaping FMD viral populations.