Goh C J, Park D, Lee J S, Sebastiani F, Hahn Y
Acta Virol. 2018;62(2):122-128. doi: 10.4149/av_2018_201.
Amalgaviridae is a family of double-stranded, monosegmented RNA viruses that are associated with plants, fungi, microsporidians, and animals. A sequence contig derived from the transcriptome of a eudicot, Cistus incanus (the family Cistaceae; commonly known as hoary rockrose), was identified as the genome sequence of a novel plant RNA virus and named Cistus incanus RNA virus 1 (CiRV1). Sequence comparison and phylogenetic analysis indicated that CiRV1 is a novel species of the genus Amalgavirus in the family Amalgaviridae. The CiRV1 genome contig has two overlapping open reading frames (ORFs). ORF1 encodes a putative replication factory matrix-like protein, while ORF2 encodes a RNA-dependent RNA polymerase (RdRp) domain. An ORF1+2 fusion protein, which functions in viral RNA replication, is produced by a +1 programmed ribosomal frameshifting (PRF) mechanism. A +1 PRF motif UUU_CGU, which matches the conserved amalgavirus +1 PRF consensus sequence UUU_CGN, was found at the boundary of CiRV1 ORF1 and ORF2. Comparison of 25 amalgavirus ORF1+2 fusion proteins revealed that only three different positions within a 13-amino acid segment were recurrently used at the boundary, possibly being selected so as not to interfere with correct folding and function of the fusion protein. CiRV1 is the first virus found to be associated with the Cistus species and may be useful for studying amalgaviruses.
融合病毒科是一类双链、单片段RNA病毒，与植物、真菌、微孢子虫和动物有关。从一种双子叶植物白苞岩蔷薇（半日花科；俗称灰白岩蔷薇）的转录组中获得的一个序列重叠群被鉴定为一种新型植物RNA病毒的基因组序列，并命名为白苞岩蔷薇RNA病毒1（CiRV1）。序列比较和系统发育分析表明，CiRV1是融合病毒科融合病毒属的一个新物种。CiRV1基因组重叠群有两个重叠的开放阅读框（ORF）。ORF1编码一种假定的复制工厂基质样蛋白，而ORF2编码一个RNA依赖的RNA聚合酶（RdRp）结构域。一种在病毒RNA复制中起作用的ORF1+2融合蛋白是通过+1程序性核糖体移码（PRF）机制产生的。在CiRV1的ORF1和ORF2边界发现了一个+1 PRF基序UUU_CGU，它与保守的融合病毒+1 PRF共有序列UUU_CGN相匹配。对25种融合病毒ORF1+2融合蛋白的比较显示，在边界处一个13个氨基酸片段内只有三个不同位置被反复使用，可能是经过选择以便不干扰融合蛋白的正确折叠和功能。CiRV1是第一种被发现与白苞岩蔷薇属植物相关的病毒，可能对研究融合病毒有用。
