Abstract
摘要:蝦類水產養殖是亞洲地區的重要產業項目之一,但近年來此相關產業持續不斷受到幾種蝦類病毒性疾病的危害,其中又以白點症病毒(white spot syndrome virus, WSSV)所引起的白點症(white spot syndrome)所造成的損失最為嚴重。然而,僅管面對此一嚴峻的挑戰與過去對此病毒的研究之努力,如今我們仍然缺乏控制白點症疾病之擴散與治療的有效方法,究其原因多肇因於白點症病毒之獨特性。白點症病毒之基因體約300 kb長,已在數年前完成解序,依基因體資訊推測,白點症病毒最多可能帶有約500個開放轉譯區(open reading frame),其中大部份的開放轉譯區序列與其他病毒或物種的基因缺乏明顯的相似性,因此增加了對白點症病毒研究的困難度。有鑑於此,本計畫之目標以建立白點症病毒基因交互作用(interactome)網路為出發點,我們計畫利用酵母菌雙雜合實驗方法對白點症病毒的主要基因進行分析,在建立此資訊後,我們將分析尋找適當的白點症病毒基因產物,進而以其為標的分析蝦類宿主細胞可以與之作用的蛋白質,期望由此可以啟始分析白點症病毒感染宿主細胞過程中的重要交互作用,進而由這些資訊分析白點症病毒在感染宿主過程中,誘發宿主細胞產生細胞自噬與計畫性細胞死亡等逆境反應的機制,最終希望分析未來經由調控宿主細胞逆境反應以對抗白點症疾病之可能性。
Abstract: White spot syndrome virus (WSSV) infection results in white spot disease in crustaceans and is causing considerable economic losses in shrimp farming industry worldwide. Despite of its stern condition and past research efforts desiring to find cures for the disease, an effective vaccine or curing medicine is still missing. Therefore, studying the interaction between WSSV and host cells will not only broaden our knowledge on this virus but also help us find effective regimens for this disease. The around 300-kb genome of WSSV encodes more than 500 putative open reading frames. Some of them have been characterized encoding structural proteins of WSSV virions and many others are expressed during virus infection. These WSSV proteins are hence good candidates for developing strategy to control white spot disease and construction of their interaction partnership is the first step marching toward that goal.
The objectives of this sub-project are to establish the interaction network maps of viral proteins. Based on this information, the crucial candidate proteins for WSSV infectious and pathological effects will be identified by analyzing those proteins with most interaction partners. These candidate proteins will be further applied for screening their interaction partners in host cells. Through this strategy, we plan to decipher the mechanisms for WSSV viral entrance into host cells and WSSV replication control. In addition, viral infection is known to elicit multiple stress responses in host cells, including apoptosis and autophagy. These stress responses are related to crustacean innate immunity, which operate to minimize the deliberate effects of viral infection. These responses, however, may lead to individual shrimp death in hope to limit the production of new virions. Induction of autophagy during infection, on the other hand, is known to be essential for some virus replication in host cells. Therefore, the role of autophagy in virus control is still on debate. Current views on the autophagy pathway suggest that autophagic degradation within limited level is beneficial to cells for eliminating damaging agents, such as intracellular pathogens and protein aggregates. Overly activated autophagy activity will then cause cell death due to the elimination of components essential to maintain cell life. How virus cope these multiple cellular response mechanisms for their benefits remains largely unknown. Recently, one open reading frame of WSSV genome was found encoding an anti-apoptotic protein, suggesting that WSSV is capable of control host cell apoptotic pathway. If WSSV also regulates autophagy, on the other hand, has not been reported yet. We plan to study autophagy regulation by WSSV during infection. With the WSSV and host protein interaction information in hands, we will further characterize those interactions between viral proteins and host proteins related to stress responses. The abilities for WSSV proteins to regulate autophagy will be examined in both Saccharomyces cerevisiae model organism and Penaeus monodon. With future aqua cultural applications in our mind, whether manipulation of stress response activities of shrimp host cells may modulate viral infection will be tested and their possibilities for clinical application will be analyzed.
Keyword(s)
白點症病毒
基因交互作用
酵母菌雙雜合實驗
逆境反應
細胞自噬
white spot syndrome virus (WSSV)
interactome
yeast two-hybrid screening
stress response
autophagy