State Key Laboratory of Marine Environmental Science, State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, Fujian, China.
State Key Laboratory of Marine Environmental Science, State-Province Joint Engineering Laboratory of Marine Bioproducts and Technology, College of Ocean and Earth Sciences, Xiamen University, Xiamen, 361102, Fujian, China; Laboratory for Marine Biology and Biotechnology, Pilot National Laboratory for Marine Science and Technology (Qingdao), China.
Dev Comp Immunol. 2020 Jun;107:103665. doi: 10.1016/j.dci.2020.103665. Epub 2020 Feb 27.
Invertebrates rely solely on the innate immune system to protect against virus infection, while the viral infection must rely on the transcriptional system of the host cell to achieve the expression of viral genes, which is naturally regulated by the host's transcriptional system. However, the mechanism of the host against viral transcription in host cells is still poorly understood in crustaceans. Previously, we found that the partial transcript sequence of a negative elongation factor E (named as CqNELF-E) was up-regulated in a differentially expressed transcriptome library of the haematopietic tissue (Hpt) cells from red claw crayfish Cherax quadricarinatus upon white spot syndrome virus (WSSV) infection, suggesting a possible role of CqNELF-E in WSSV-host interaction. In the present study, we revealed the function of CqNELF-E. The full-length cDNA sequence of CqNELF-E was identified with 1726 bp from red claw crayfish, which contained an open reading frame of 816 bp, encoding 271 amino acids. Amino acid sequencing analysis revealed that the CqNELF-E had a conserved RNA recognition motif (RRM) and a leucine zipper motif (LZM). Tissue distribution analysis showed that CqNELF-E was widely expressed in various tissues with the highest expression in muscle, relatively abundant in Hpt and the lowest presence in heart. Interestingly, the gene expression of CqNELF-E was significantly up-regulated at both 6 and 12 hpi after WSSV infection in Hpt cell cultures in red claw crayfish. In addition, the expression of both the viral immediately early gene (IE) 1 (IE1) and a late gene envelope protein VP28 were significantly increased after gene silencing of CqNELF-E in Hpt cells, indicating the potential suppression role of CqNELF-E against the viral infection. Further study revealed that the CqNELF-E had an inhibitory effect on the promoter activity of WSSV IE genes WSV051, WSV069 (IE1) and WSV083 by a dual luciferase reporter gene assay. Taken together, these results suggest that CqNELF-E plays an antiviral role, probably via inhibition on the viral transcription activity in WSSV infection in a crustacean.
无脊椎动物仅依靠先天免疫系统来抵抗病毒感染，而病毒感染必须依靠宿主细胞的转录系统来实现病毒基因的表达，这是由宿主转录系统自然调控的。然而，甲壳动物宿主细胞中宿主对病毒转录的机制仍知之甚少。之前，我们在克氏原螯虾(Cherax quadricarinatus)造血组织(Hpt)细胞差异表达转录组文库中发现，一种负延伸因子 E 的部分转录序列(CqNELF-E)在白斑综合征病毒(WSSV)感染后上调，表明 CqNELF-E 可能在 WSSV-宿主相互作用中发挥作用。在本研究中，我们揭示了 CqNELF-E 的功能。我们从克氏原螯虾中鉴定出 CqNELF-E 的全长 cDNA 序列，其包含 1726bp 的开放阅读框，编码 271 个氨基酸。氨基酸序列分析表明，CqNELF-E 具有保守的 RNA 识别基序(RRM)和亮氨酸拉链基序(LZM)。组织分布分析表明，CqNELF-E 在各种组织中广泛表达，在肌肉中表达最高，在 Hpt 中相对丰富，在心脏中表达最低。有趣的是，在 WSSV 感染克氏原螯虾 Hpt 细胞后 6 和 12 小时，CqNELF-E 的基因表达在 Hpt 细胞中显著上调。此外，在 Hpt 细胞中沉默 CqNELF-E 后，病毒的早期基因 IE1 和晚期基因包膜蛋白 VP28 的表达均显著增加，表明 CqNELF-E 可能具有抑制病毒感染的作用。进一步研究表明，CqNELF-E 通过双荧光素酶报告基因检测对 WSSV IE 基因 WSV051、WSV069(IE1)和 WSV083 的启动子活性具有抑制作用。综上所述，这些结果表明，CqNELF-E 在甲壳动物 WSSV 感染中发挥抗病毒作用，可能通过抑制病毒转录活性来发挥作用。
