Wu Bin, Zhang Xichen, Gong Pengtao, Li Mingying, Ding He, Xin Caiyan, Zhao Na, Li Jianhua
College of Veterinary Medicine, Jilin University, 5333 Xi'an Road, Changchun, 130062, China.
Virus Genes. 2016 Apr;52(2):244-52. doi: 10.1007/s11262-016-1295-0. Epub 2016 Feb 12.
Protozoa double-stranded (ds) RNA viruses have been described in Trichomonas, Giardia, and Leishmania. In this study, dsRNA and virus-like particles (approximately 30 nm in diameter) were discovered in Eimeria tenella sporulated oocysts. The complete genome of this novel dsRNA virus was sequenced using a three-step strategy. The sequencing results showed that the complete genome sequence was 6006 bp containing two open reading frames (ORFs) (2367 bp for ORF1 and 3216 bp for ORF2) with a five-nucleotide overlap (UGA/UG). The predicted ORF1 and ORF2 encoded a putative capsid protein of 788 amino acids (84.922 kDa) and a putative RNA-dependent RNA polymerase (RdRp) protein of 1071 amino acids (118.190 kDa). BLASTp analysis showed that the amino acid sequences for the E. tenella virus shared similarity with the E. brunetti RNA virus, with 29% homology in capsid proteins and 36% in RDRP proteins. The two untranslated regions were 349 bp (5' UTR) and 78 bp (3' UTR). The complete genome sequence of the E. tenella virus resembled characteristics of the Totiviridae family, indicating that this virus was a novel member of Totiviridae. Surprisingly, phylogenetic analysis showed that the E. tenella virus, E. brunetti RNA virus 1, and Mycoviruses were clustered into the genus Victorivirus and separated from the reported protozoa viruses, strongly suggesting a novel Eimeriaviruses subgenus. To the best of our knowledge, this is the first report for the complete genome sequence of the E. tenella virus. Using the nomenclature generally adopted for viruses, this new isolate was named E. tenella RNA virus 1. This study provides a foundation basis for further research on the biological characteristics of Eimeriaviruses.
原生动物双链（ds）RNA病毒已在滴虫、贾第虫和利什曼原虫中被描述。在本研究中，在柔嫩艾美耳球虫孢子化卵囊中发现了dsRNA和病毒样颗粒（直径约30纳米）。使用三步策略对这种新型dsRNA病毒的完整基因组进行了测序。测序结果表明，完整基因组序列为6006 bp，包含两个开放阅读框（ORF）（ORF1为2367 bp，ORF2为3216 bp），有一个五核苷酸重叠（UGA/UG）。预测的ORF1和ORF2分别编码一个推定的788个氨基酸（84.922 kDa）的衣壳蛋白和一个推定的1071个氨基酸（118.190 kDa）的RNA依赖性RNA聚合酶（RdRp）蛋白。BLASTp分析表明，柔嫩艾美耳球虫病毒的氨基酸序列与布氏艾美耳球虫RNA病毒相似，衣壳蛋白同源性为29%，RDRP蛋白同源性为36%。两个非翻译区分别为349 bp（5'UTR）和78 bp（3'UTR）。柔嫩艾美耳球虫病毒的完整基因组序列类似于全病毒科的特征，表明该病毒是全病毒科的一个新成员。令人惊讶的是，系统发育分析表明，柔嫩艾美耳球虫病毒、布氏艾美耳球虫RNA病毒1和真菌病毒聚集在Victorivirus属中，并与已报道的原生动物病毒分离，强烈提示有一个新的艾美耳球虫病毒亚属。据我们所知，这是关于柔嫩艾美耳球虫病毒完整基因组序列的首次报道。使用病毒通常采用的命名法，这种新分离株被命名为柔嫩艾美耳球虫RNA病毒1。本研究为进一步研究艾美耳球虫病毒的生物学特性提供了基础依据。
