Green Timothy J, Benkendorff Kirsten, Robinson Nick, Raftos David, Speck Peter
School of Biological Sciences and Australian Seafood Cooperative Research Centre, Flinders University, GPO Box 2100, Adelaide, SA 5001, Australia.
Marine Ecology Research Centre, Southern Cross University, P.O. Box 157, Lismore, NSW 2480, Australia.
Fish Shellfish Immunol. 2014 Aug;39(2):492-7. doi: 10.1016/j.fsi.2014.06.010. Epub 2014 Jun 17.
Oyster farming is one of the most important aquaculture industries in the world. However, its productivity is increasingly limited by viral disease and we do not yet have management practices, such as protective vaccination, that can control these disease outbreaks. Hence, in the current study we investigated the expression of known anti-viral genes in oysters (Crassostrea gigas) in response to primary and secondary encounter with a virus associated molecular pattern (dsRNA), and tested whether a common form of epigenetic gene regulation (DNA methylation) was associated with the expression of these anti-viral genes. Injection of dsRNA into the adductor muscle resulted in the rapid and transient expression of virus recognition receptors (TLR & MDA5), whereas several anti-viral signalling (IRF & SOC-1) and effector (PKR & viperin) genes were still up-regulated at one week post primary challenge (p < 0.05). This primary encounter with dsRNA appeared to deplete the immune system because anti-viral gene induction was absent in the gills when oysters were given a second injection of dsRNA at 1-week post-primary injection. The expression of DNA methylation genes (DNMT1, DNMT3b, TDG, TET2) and DNA methylation profiles up-stream of specific anti-viral genes (STING, SOC-1 & Viperin) did not change in response to dsRNA injection (p > 0.05). These results collectively suggest that C. gigas does not have an enhanced anti-viral gene response (immune-priming) to secondary dsRNA challenge and that the sustained up-regulation of anti-viral signalling and effector genes following primary challenge is unlikely to be associated with upstream DNA methylation levels.
牡蛎养殖是世界上最重要的水产养殖业之一。然而，其生产力越来越受到病毒性疾病的限制，而且我们目前还没有诸如保护性疫苗接种等管理措施来控制这些疾病的爆发。因此，在本研究中，我们调查了牡蛎（太平洋牡蛎）中已知抗病毒基因在初次和再次接触病毒相关分子模式（双链RNA）时的表达情况，并测试了一种常见的表观遗传基因调控形式（DNA甲基化）是否与这些抗病毒基因的表达相关。向闭壳肌注射双链RNA导致病毒识别受体（TLR和MDA5）快速短暂表达，而几种抗病毒信号（IRF和SOC-1）和效应器（PKR和viperin）基因在初次攻击后一周仍上调（p < 0.05）。初次接触双链RNA似乎耗尽了免疫系统，因为在初次注射后1周再次给牡蛎注射双链RNA时，鳃中没有出现抗病毒基因的诱导。DNA甲基化基因（DNMT1、DNMT3b、TDG、TET2）的表达以及特定抗病毒基因（STING、SOC-1和Viperin）上游的DNA甲基化谱在注射双链RNA后没有变化（p > 0.05）。这些结果共同表明，太平洋牡蛎对再次的双链RNA攻击没有增强的抗病毒基因反应（免疫致敏），并且初次攻击后抗病毒信号和效应器基因的持续上调不太可能与上游DNA甲基化水平相关。
