Cyprinid herpesvirus 2 (CyHV-2), which infects goldfish and crucian carp causing high mortality, is an emerging viral pathogen worldwide. The genome of CyHV-2 is large and comprises double-stranded DNA, including several genes similar to cyprinid herpesvirus 1, ictalurid herpesvirus-1, cyprinid herpesvirus 3, and ranid herpesvirus-1. Genes of DNA viruses are expressed in three temporal phases: immediate-early (IE), early (E), and late (L) genes. Viral IE genes initiate transcription as soon as the virus enters the host, without viral DNA replication. IE gene products enable the efficient expression of E and L genes or regulate the host to initiate virus replication. In the present study, five IE genes of CyHV-2 were identified, including open reading frame (ORF)54, ORF121, ORF141, ORF147, and ORF155. Time course analysis and reverse transcription polymerase chain reaction confirmed five IE genes, thirty-four E genes, and thirty-nine L genes. In addition, all 150 ORFs identified in the CyHV-2 genome are transcribed, and are expressed in chronological order, similar to other herpesviruses. This study is the first to identify the IE genes of CyHV-2, which will provide more information for viral molecular characterization.

中文翻译：

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塞浦路斯疱疹病毒2的早期基因的鉴定

鲤鱼疱疹病毒2（CyHV-2）感染金鱼和cru鱼，导致高死亡率，是全世界一种新兴的病毒病原体。CyHV-2的基因组很大，由双链DNA组成，包括与cyprinid疱疹病毒1，ictalurid疱疹病毒1，cyprinid疱疹病毒3和ranid疱疹病毒1相似的几个基因。DNA病毒的基因在三个时间阶段表达：立即早期（IE），早期（E）和晚期（L）基因。病毒IE基因在病毒进入宿主后立即启动转录，而没有病毒DNA复制。IE基因产物可实现E和L基因的有效表达或调节宿主以启动病毒复制。在本研究中，鉴定了CyHV-2的5个IE基因，包括开放阅读框（ORF）54，ORF121，ORF141，ORF147和ORF155。时程分析和逆转录聚合酶链反应确认了5个IE基因，34个E基因和39个L基因。另外，与其他疱疹病毒相似，CyHV-2基因组中鉴定的所有150个ORF均被转录并按时间顺序表达。这项研究是首次鉴定CyHV-2的IE基因，这将为病毒分子表征提供更多信息。