INRS-Institut Armand Frappier, Université du Québec, 531 Boul. des Prairies, Laval, Quebec, Canada.
J Virol. 2011 Oct;85(19):10069-78. doi: 10.1128/JVI.00625-11. Epub 2011 Jul 20.
The Acheta domesticus densovirus (AdDNV), isolated from crickets, has been endemic in Europe for at least 35 years. Severe epizootics have also been observed in American commercial rearings since 2009 and 2010. The AdDNV genome was cloned and sequenced for this study. The transcription map showed that splicing occurred in both the nonstructural (NS) and capsid protein (VP) multicistronic RNAs. The splicing pattern of NS mRNA predicted 3 nonstructural proteins (NS1 [576 codons], NS2 [286 codons], and NS3 [213 codons]). The VP gene cassette contained two VP open reading frames (ORFs), of 597 (ORF-A) and 268 (ORF-B) codons. The VP2 sequence was shown by N-terminal Edman degradation and mass spectrometry to correspond with ORF-A. Mass spectrometry, sequencing, and Western blotting of baculovirus-expressed VPs versus native structural proteins demonstrated that the VP1 structural protein was generated by joining ORF-A and -B via splicing (splice II), eliminating the N terminus of VP2. This splice resulted in a nested set of VP1 (816 codons), VP3 (467 codons), and VP4 (429 codons) structural proteins. In contrast, the two splices within ORF-B (Ia and Ib) removed the donor site of intron II and resulted in VP2, VP3, and VP4 expression. ORF-B may also code for several nonstructural proteins, of 268, 233, and 158 codons. The small ORF-B contains the coding sequence for a phospholipase A2 motif found in VP1, which was shown previously to be critical for cellular uptake of the virus. These splicing features are unique among parvoviruses and define a new genus of ambisense densoviruses.
阿彻塔 domesticus 浓核病毒 (AdDNV) 从蟋蟀中分离出来，在欧洲已经流行了至少 35 年。自 2009 年和 2010 年以来，美国商业饲养的蟋蟀也发生了严重的流行病。本研究克隆并测序了 AdDNV 基因组。转录图谱显示，非结构 (NS) 和衣壳蛋白 (VP) 多顺反子 RNA 均发生剪接。NSmRNA 的剪接模式预测了 3 种非结构蛋白 (NS1[576 个密码子]、NS2[286 个密码子]和 NS3[213 个密码子])。VP 基因盒包含两个 VP 开放阅读框 (ORF)，分别为 597(ORF-A)和 268(ORF-B)个密码子。VP2 序列通过 N 端 Edman 降解和质谱分析与 ORF-A 相对应。杆状病毒表达的 VPs 与天然结构蛋白的质谱、测序和 Western blot 分析表明，VP1 结构蛋白是通过剪接 (剪接 II) 将 ORF-A 和 -B 连接产生的，消除了 VP2 的 N 端。这种剪接导致嵌套的 VP1(816 个密码子)、VP3(467 个密码子)和 VP4(429 个密码子)结构蛋白。相比之下，ORF-B 内的两个剪接 (Ia 和 Ib) 去除了内含子 II 的供体位点，导致 VP2、VP3 和 VP4 的表达。ORF-B 也可能编码 268、233 和 158 个密码子的几种非结构蛋白。小的 ORF-B 包含 VP1 中发现的磷脂酶 A2 基序的编码序列，先前的研究表明该基序对病毒的细胞摄取至关重要。这些剪接特征在细小病毒中是独特的，并定义了一个新的 ambisense 浓核病毒属。
