National Pathogen Collection Center for Aquatic Animals, Shanghai Ocean University, Shanghai 201306, China.
Key Laboratory of Freshwater Aquatic Genetic Resources, Ministry of Agriculture Shanghai Ocean University, Shanghai 201306, China.
Viruses. 2020 Sep 7;12(9):994. doi: 10.3390/v12090994.
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.
鲤鱼疱疹病毒 2（CyHV-2）是一种新兴的病毒性病原体，可感染金鱼和鲫鱼，导致高死亡率。该病毒的基因组较大，由双链 DNA 组成，包括几个与鲤鱼疱疹病毒 1、美洲鳗疱疹病毒 1、鲤鱼疱疹病毒 3 和牛蛙疱疹病毒 1 相似的基因。DNA 病毒的基因在三个时间阶段表达：即刻早期（IE）、早期（E）和晚期（L）基因。病毒的 IE 基因在病毒进入宿主后立即启动转录，而无需病毒 DNA 复制。IE 基因产物能够有效地表达 E 和 L 基因，或调节宿主启动病毒复制。在本研究中，鉴定了 CyHV-2 的五个 IE 基因，包括开放阅读框（ORF）54、ORF121、ORF141、ORF147 和 ORF155。时程分析和反转录聚合酶链反应证实了五个 IE 基因、三十四个 E 基因和三十九个 L 基因的存在。此外，CyHV-2 基因组中鉴定的所有 150 个 ORF 都被转录，并按照时间顺序表达，类似于其他疱疹病毒。本研究首次鉴定了 CyHV-2 的 IE 基因，这将为病毒的分子特征提供更多信息。
