Transcriptional mapping in Chilo iridescent virus infections
Transcriptional mapping in Chilo iridescent virus infections
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DOI：
10.1007/s00705-003-0232-4
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发表时间：
2004-04-01
影响因子：
2.7
通讯作者：
Bilimoria, SL
中科院分区：
文献类型：
--
作者：
D'Costa, SM;Yao, HJ;Bilimoria, SL
二化螟虹彩病毒（Chilo iridescent virus，CIV）属于虹彩病毒科（Iridoviridae），是一种二十面体的细胞质DNA病毒，基因组大，呈线性和环状排列。以前的研究感染细胞特异性多肽建议CIV基因表达的时间调节。最近，我们证明了三个时间类在转录水平上，在CIV感染的云杉芽虫，细胞系。我们还证明了一个转录级联与阳性和阴性对照。在本文中，我们将所有可检测到的病毒转录本分配到各自的时间类，并使用来自基因组文库的限制性片段对其进行映射。超过90%的基因组是转录活跃的，至少有四个主要的即时早期转录簇和至少三个延迟早期转录簇。在整个基因组中观察到晚期转录物。在基因组中，三个时间类别中的每一个都至少有一个专属区域。我们将转录区域与CIV基因组上的ORF相关联，并表明在专用区域中的已知ORF通常与大型DNA病毒的阶段特异性要求一致。我们的数据还表明存在5'或3'共末端转录本。这是虹彩病毒属成员的第一个完整的转录图谱。
Chilo iridescent virus (CIV) belongs to the family Iridoviridae, which are icosahedral cytoplasmic DNA viruses with large, linear, and circularly permuted genomes. Previous studies on infected-cell-specific polypeptides suggested temporal regulation of CIV gene expression. Recently, we demonstrated three temporal classes at the transcriptional level, in CIV infections of a spruce budworm, cell line. We also demonstrated a transcriptional cascade with positive and negative control. In this paper, we assign all detectable viral transcripts into respective temporal classes and map them using restriction fragments from a genomic library. More than 90 percent of the genome is transcriptionally active with at least four major clusters of immediate-early transcription and at least three delayed-early clusters. Late transcripts were observed throughout the genome. There was at least one exclusive region in the genome for each of the three temporal classes. We correlated transcribed regions with ORFs on the CIV genome and showed that known ORFs in the exclusive regions are generally consistent with phase-specific requirements of large DNA viruses. Our data also suggest the presence of 5' or 3' coterminal transcripts. This is the first complete transcription map for a member of the genus Iridovirus.