Hillman B I, Halpern B T, Brown M P
Department of Plant Pathology, Rutgers University, New Brunswick, New Jersey 08903.
Virology. 1994 Jun;201(2):241-50. doi: 10.1006/viro.1994.1289.
We have sequenced overlapping complementary DNA clones representing the viral double-stranded (ds) RNA from hypovirulent strain NB58 of the chestnut blight fungus Cryphonectria parasitica. Cryphonectria hypovirus 2-NB58 (CHV2-NB58) dsRNA contains 12,507 base pairs, excluding the poly(A) tail at the 3' end of the plus strand, and is organizationally similar to the largest dsRNA from the virus of strain EP713 (CHV1-713; identical to HAV; Shapira et al., (1991), EMBO J. 10, 731-739). CHV2-NB58 and CHV1-713 dsRNAs share approximately 60% nucleotide sequence identity. On the poly(A)-containing strand of CHV2-NB58, a 487-residue nontranslated region precedes two open reading frames, designated ORF A (438 codons) and ORF B (3291 codons). The connecting pentanucleotide sequence UAAUG (1802-1806) terminates ORF A and initiates ORF B. In contrast to the 69-kDa ORF A product of CHV1-713, the 50-kDa CHV2-NB58 ORF A product did not undergo autoproteolysis under the conditions tested, nor were motifs associated with cysteine proteases present in the CHV2-NB58 ORF A sequence. CHV2-NB58 ORF B products appear to be homologous with CHV1-713 ORF B products, and the motifs involved in autoproteolysis of the N-terminal 48 kDa of CHV1-713 ORF B were identified in the CHV2-NB58 ORF B product. Motifs associated with RNA polymerase and helicase activities were highly conserved between CHV2-NB58 and CHV1-713 and were found at similar genomic positions in the C-terminal half of ORF B.
我们已对来自栗疫病菌Cryphonectria parasitica低毒力菌株NB58的病毒双链（ds）RNA的重叠互补DNA克隆进行了测序。低毒力栗疫菌病毒2-NB58（CHV2-NB58）双链RNA包含12,507个碱基对，不包括正链3'端的聚腺苷酸尾，并且在组织上与菌株EP713病毒（CHV1-713；与HAV相同；Shapira等人，(1991)，《欧洲分子生物学组织杂志》10，731-739）的最大双链RNA相似。CHV2-NB58和CHV1-713双链RNA具有约60%的核苷酸序列同一性。在CHV2-NB58的含聚腺苷酸链上，一个487个残基的非翻译区位于两个开放阅读框之前，分别命名为ORF A（438个密码子）和ORF B（3291个密码子）。连接五核苷酸序列UAAUG（1802-1806）终止ORF A并启动ORF B。与CHV1-713的69 kDa ORF A产物不同，50 kDa的CHV2-NB58 ORF A产物在测试条件下未发生自蛋白水解，并且CHV2-NB58 ORF A序列中也不存在与半胱氨酸蛋白酶相关的基序。CHV2-NB58 ORF B产物似乎与CHV1-713 ORF B产物同源，并且在CHV2-NB58 ORF B产物中鉴定出了参与CHV1-713 ORF B N端48 kDa自蛋白水解的基序。与RNA聚合酶和螺旋酶活性相关的基序在CHV2-NB58和CHV1-713之间高度保守，并且在ORF B的C端一半的相似基因组位置被发现。
