Sección Virología, Facultad de Ciencias, Universidad de la República, Iguá 4225, Montevideo 11400, Uruguay.
Infect Genet Evol. 2013 Oct;19:23-31. doi: 10.1016/j.meegid.2013.06.017. Epub 2013 Jun 24.
Porcine Circovirus Type 2 (PCV2) is a worldwide distributed virus and is considered an important emerging pathogen related to several distinct disease syndromes in pigs. Genomic structure consists of three major open reading frames (ORFs). ORF1 (rep gene) encodes replication-related proteins, ORF2 (cap gene) encodes the capsid protein and ORF3 encodes a protein putatively involved in virus-induced apoptosis. Based on cap gene sequences, PCV2 strains are classified into two main genotypes, PCV2a with five clusters (2A-2E) and PCV2b with three clusters (1A-1C). According to previous theoretical studies, PCV2 strains can eventually undergo intra and inter-genotype recombination, mainly within the rep gene. Ever since, several evidences of recombination in the field have been reported and confirmed this hypothesis. In South America, data regarding molecular characterization of PCV2 strains is still scant. Genotyping studies in the region have concluded that PCV2b is the predominant circulating genotype in the region and till now, no recombinant strains have ever been reported. In this work we thoroughly characterized at the molecular level Uruguayan PCV2 strains by extensive sequence data analysis. Moreover, recombination software tools were applied to explore and characterize eventual occurrence of natural recombination events. Two recombinant PCV2 strains were detected in this study, as a consequence of an inter-genotype recombination event between PCV2b-1A and PCV2a-2D, as the major and minor parent, respectively. According to recombination software analysis, in both cases the event occurred within the ORF1. Herein, extensive viral sequence dataset is provided, including the characterization of the first PCV2 recombinant strains ever reported in South America. Additionally, our results suggested a multi-centered source of PCV2 infection in Uruguay, which probably involved Brazilian and European origins.
猪圆环病毒 2 型（PCV2）是一种在全球范围内分布的病毒，被认为是与猪的几种不同疾病综合征有关的重要新兴病原体。基因组结构由三个主要开放阅读框（ORF）组成。ORF1（rep 基因）编码与复制相关的蛋白，ORF2（cap 基因）编码衣壳蛋白，ORF3 编码一种推测与病毒诱导的细胞凋亡有关的蛋白。根据 cap 基因序列，PCV2 株可分为两个主要基因型，PCV2a 有五个聚类（2A-2E）和 PCV2b 有三个聚类（1A-1C）。根据之前的理论研究，PCV2 株最终可以发生种内和种间重组，主要发生在 rep 基因内。此后，已有研究报道并证实了该领域的重组证据。在南美洲，关于 PCV2 株的分子特征的数据仍然很少。该地区的基因分型研究得出的结论是，PCV2b 是该地区主要流行的基因型，到目前为止，还没有报告过重组株。在这项工作中，我们通过广泛的序列数据分析对乌拉圭的 PCV2 株进行了分子水平的彻底特征分析。此外，应用重组软件工具来探索和描述自然重组事件的发生。本研究检测到两株重组 PCV2 株，是 PCV2b-1A 和 PCV2a-2D 之间的种间重组事件的结果，分别为主要和次要亲本。根据重组软件分析，在这两种情况下，该事件都发生在 ORF1 内。在此，提供了广泛的病毒序列数据集，包括首次在南美洲报道的 PCV2 重组株的特征。此外，我们的结果表明，乌拉圭的 PCV2 感染存在多中心来源，可能涉及巴西和欧洲的起源。
