Hillman B I, Foglia R, Yuan W
Department of Plant Pathology, Cook College, Rutgers University, Foran Hall, 59 Dudley Road, New Brunswick, New Jersey 08901-8520, USA.
Virology. 2000 Oct 10;276(1):181-9. doi: 10.1006/viro.2000.0548.
Cryphonectria parasitica hypovirus 3-Grand Haven 2 (CHV3-GH2) is the most recently characterized member of the Hypoviridae family of viruses associated with hypovirulence of the chestnut blight fungus. Isolates of CHV3-GH2 contain either three or four double-stranded (ds) RNAs that are visible on ethidium bromide-stained agarose or polyacrylamide gels. Only the largest dsRNA appears to be required for virus infectivity, and was characterized previously (C. D. Smart et al., 1999, Virology 265, 66-73). In this study, we report the cloning, sequencing, and analysis of the other three dsRNAs. Sizes of the accessory dsRNAs are 3.6 kb (dsRNA 2), 1.9 kb (dsRNA 3), and 0.9 kb (dsRNA 4), compared to 9.8 kb for the genomic dsRNA segment (dsRNA 1). All three accessory dsRNA species are polyadenylated on the 3'-end of one strand, as is genomic dsRNA. DsRNA 2 represents a defective form of dsRNA 1, with the 5'-terminal 1.4 kb derived from the 5'-end of dsRNA 1 and the 3'-terminal 2.2 kb from the 3'-end of dsRNA 1. A single major open reading frame (ORF) is evident from deduced translations of dsRNA 2. The deduced translation product is a 91-kDa protein that represents a fusion consisting of the entire N-terminal protease and the entire putative helicase domain. DsRNAs 3 and 4 represent satellite RNAs that share very little sequence with dsRNA 1 and 2. DsRNA 4 is 937 nucleotides, excluding the poly(A)(+). The first AUG of the polyadenylated strand of dsRNA 4 occurs eight residues in from the 5'-terminus and would initiate the largest ORF on dsRNA 4, with the coding capacity for a 9.4-kDa protein. Within the deduced ORF and approximately 100 nucleotides from the 5'-end of dsRNA 4 is a 22-base sequence that is identical to sequences found in the nontranslated leaders of dsRNAs 1 and 2. DsRNA 3 accumulation in infected cultures varied, but it was less abundant than dsRNA 4. DsRNA 3 was found to represent a head-to-tail dimer of dsRNA 4 linked by a poly(A)/(U) stretch of 40-70 residues.
栗疫病菌低毒病毒3 - 大港湾2型（CHV3 - GH2）是与栗疫病菌低毒力相关的病毒科中最新鉴定的成员。CHV3 - GH2分离株含有三条或四条双链（ds）RNA，在溴化乙锭染色的琼脂糖凝胶或聚丙烯酰胺凝胶上可见。似乎只有最大的dsRNA是病毒感染性所必需的，并且先前已对其进行了表征（C. D. Smart等人，1999年，《病毒学》265卷，66 - 73页）。在本研究中，我们报告了其他三条dsRNA的克隆、测序和分析。与基因组dsRNA片段（dsRNA 1）的9.8 kb相比，辅助dsRNA的大小分别为3.6 kb（dsRNA 2）、1.9 kb（dsRNA 3）和0.9 kb（dsRNA 4）。所有三条辅助dsRNA种类在一条链的3'末端都进行了多聚腺苷酸化，基因组dsRNA也是如此。DsRNA 2代表dsRNA 1的缺陷形式，其5'末端的1.4 kb来自dsRNA 1的5'末端，3'末端的2.2 kb来自dsRNA 1的3'末端。从dsRNA 2的推导翻译中可以明显看出一个单一的主要开放阅读框（ORF）。推导的翻译产物是一种91 kDa的蛋白质，它是由整个N端蛋白酶和整个假定的解旋酶结构域组成的融合蛋白。DsRNA 3和4代表卫星RNA，与dsRNA 1和2几乎没有序列共享。DsRNA 4为937个核苷酸，不包括多聚（A）（+）。dsRNA 4多聚腺苷酸化链的第一个AUG从5'末端起八个残基处出现，并将启动dsRNA 4上最大的ORF，编码能力为一种9.4 kDa的蛋白质。在推导的ORF内且距dsRNA 4的5'末端约100个核苷酸处是一个22个碱基的序列，与dsRNA 1和2的非翻译前导序列中发现的序列相同。感染培养物中dsRNA 3的积累情况各不相同，但它比dsRNA 4含量少。发现dsRNA 3代表由40 - 70个残基的多聚（A）/（U）片段连接的dsRNA 4的头对头二聚体。
