在過去二十年，蝦類養殖產業一直遭受到白點病 (WSD) 的威脅。白點病是一種由白點症病毒 (WSSV) 所引起的嚴重疾病。這種疾病造成的高死亡率使全球的蝦類養殖產業蒙受了嚴重的經濟損失。儘管了解白點症病毒的致命機制是何等重要，但至今卻仍無法清楚地了解。在本實驗室之前的研究中發現，受白點症病毒感染之白蝦血球組織發生了代謝的變化，包含了葡萄糖消耗及乳酸生成的增加。這種有氧糖解 (aerobic glycolysis) 的現象也同樣在腫瘤細胞或其他高度增生的細胞中被發現，而此現象也被稱為瓦伯效應 (Warburg effect)。目前研究發現，哺乳動物中存在四種丙酮酸激酶異構型 (PK-M1、PK-M2、PK-L及PK-R)。而最近在腫瘤細胞的研究則指出為了使腫瘤細胞進行有氧糖解，細胞中的PK-M1異構型轉變為PK-M2型是必需的。雖然對於白點症病毒引起的類瓦伯效應已經展開相關的研究，但對其分子調控機制則尚未了解。在這個研究中，我們探討了蝦類丙酮酸激酶與白點症病毒引起的類瓦伯效應之間的關係。在這研究中發現白蝦丙酮酸激酶 (LvPK) 基因有三種型態，分別稱為LvPK1、LvPK2及LvPK3。目前的結果顯示此三種型態的丙酮酸激酶可能是從同一個基因座藉選擇性剪接而來。除了轉譯區，此外在結果中發現選擇性剪接也發生在5’端及3’端未轉譯區。三種丙酮酸激酶在蝦組織中有不同的表現形式，因此他們可能在細胞中參與不同的作用。此外也藉由半定量反轉錄聚合酶鏈鎖反應 (RT-PCR) 偵測三者在白點症病毒感染後的反應。結果顯示LvPK3最有可能參與有氧糖解反應，但仍需更進一步的研究去分析其在白點症病毒引起的類瓦伯效應中所扮演的角色。

For over two decades, the shrimp aquaculture industry has been threatened by white spot disease (WSD). WSD is a serious viral disease caused by WSSV, the white spot syndrome virus. This disease can cause high mortality and severe economic losses worldwide in the shrimp industry. Despite its importance, the pathogenesis of WSSV remains unclear. In our previous study, WSSV-infected hemocytes were found to have a metabolic alternation involving increased glucose consumption and lactate production. In tumors and other highly proliferative cells, aerobic glycolysis is also found, and has been named the Warburg effect. In mammals, four pyruvate kinase (PK) isoforms have been identified (PK-M1, PK-M2, PK-L and PK-R). Recent tumor research has shown that in order to promote aerobic glycolysis in tumor cells, it is essential to switch from PK-M1 to PK-M2. Although the WSSV-induced Warburg-like effect has been investigated, the molecular regulation details in this process are still unclear. In this research we investigated the involvement of shrimp PK in a WSSV-induced Warburg effect. The pyruvate kinase gene was identified from Litopenaeus vannamei. Three isoforms were isolated, named LvPK1, LvPK2 and LvPK3. Our data suggest that these three isoform are generated from a single locus subject to alternative splicing. We found that, not only the coding regions, the alternative splicing events of PK generation are occurred on 5’UTR and 3’UTR. LvPKs 1-3 have different expression patterns in shrimp tissue. Therefore, they are assumed to play different physical roles. Responses of LvPks after WSSV infection in different tissues were also investigated using semi-quantitative RT-PCR. We found that LvPK3 may be most related to aerobic glycolysis. Further research is necessary, however, to evaluate its role in the WSSV-induced Warburg-like effect.

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