Jancovich James K, Mao Jinghe, Chinchar V Gregory, Wyatt Christopher, Case Steven T, Kumar Sudhir, Valente Graziela, Subramanian Sankar, Davidson Elizabeth W, Collins James P, Jacobs Bertram L
School of Life Sciences, Arizona State University, Tempe, AZ 85287-4601, USA.
Virology. 2003 Nov 10;316(1):90-103. doi: 10.1016/j.virol.2003.08.001.
Disease is among the suspected causes of amphibian population declines, and an iridovirus and a chytrid fungus are the primary pathogens associated with amphibian mortalities. Ambystoma tigrinum virus (ATV) and a closely related strain, Regina ranavirus (RRV), are implicated in salamander die-offs in Arizona and Canada, respectively. We report the complete sequence of the ATV genome and partial sequence of the RRV genome. Sequence analysis of the ATV/RRV genomes showed marked similarity to other ranaviruses, including tiger frog virus (TFV) and frog virus 3 (FV3), the type virus of the genus Ranavirus (family Iridoviridae), as well as more distant relationships to lymphocystis disease virus, Chilo iridescent virus, and infectious spleen and kidney necrosis virus. Putative open reading frames (ORFs) in the ATV sequence identified 24 genes that appear to control virus replication and block antiviral responses. In addition, >50 other putative genes, homologous to ORFs in other iridoviral genomes but of unknown function, were also identified. Sequence comparison performed by dot plot analysis between ATV and itself revealed a conserved 14-bp palindromic repeat within most intragenic regions. Dot plot analysis of ATV vs RRV sequences identified several polymorphisms between the two isolates. Finally, a comparison of ATV and TFV genomic sequences identified genomic rearrangements consistent with the high recombination frequency of iridoviruses. Given the adverse effects that ranavirus infections have on amphibian and fish populations, ATV/RRV sequence information will allow the design of better diagnostic probes for identifying ranavirus infections and extend our understanding of molecular events in ranavirus-infected cells.
疾病是两栖动物种群数量下降的疑似原因之一，虹彩病毒和壶菌是与两栖动物死亡相关的主要病原体。虎纹钝口螈病毒（ATV）和一种密切相关的毒株，即里贾纳蛙病毒（RRV），分别与亚利桑那州和加拿大的蝾螈死亡事件有关。我们报告了ATV基因组的完整序列和RRV基因组的部分序列。对ATV/RRV基因组的序列分析表明，它们与其他蛙病毒有显著相似性，包括虎蛙病毒（TFV）和蛙病毒3（FV3），蛙病毒3是蛙病毒属（虹彩病毒科）的模式病毒，此外，它们与淋巴囊肿病病毒、稻纵卷叶螟虹彩病毒以及传染性脾肾坏死病毒的关系更为疏远。ATV序列中的推定开放阅读框（ORF）鉴定出24个似乎控制病毒复制并阻断抗病毒反应的基因。此外，还鉴定出了50多个与其他虹彩病毒基因组中的ORF同源但功能未知的推定基因。通过点图分析对ATV与其自身进行的序列比较揭示了大多数基因区域内一个保守的14碱基对回文重复序列。对ATV与RRV序列进行的点图分析确定了这两个分离株之间的几个多态性。最后，对ATV和TFV基因组序列的比较确定了与虹彩病毒高重组频率一致的基因组重排。鉴于蛙病毒感染对两栖动物和鱼类种群的不利影响，ATV/RRV序列信息将有助于设计更好的诊断探针来识别蛙病毒感染，并扩展我们对蛙病毒感染细胞中分子事件的理解。
