Institute of Modern Aquaculture Science and Engineering (IMASE), Guangzhou Key Laboratory of Subtropical Biodiversity and Biomonitoring, Guangdong Provincial Key Laboratory for Healthy and Safe Aquaculture, College of Life Science, South China Normal University, Guangzhou, 510631, PR China.
College of Marine Sciences, South China Agricultural University, Guangzhou, 510642, China.
Fish Shellfish Immunol. 2019 Oct;93:977-985. doi: 10.1016/j.fsi.2019.08.056. Epub 2019 Aug 23.
C-type lectins (CTLs), which bind carbohydrates in a Ca-dependent manner, are involved in many cellular activities, especially immunity. CTLs play important roles in both the antibacterial and the antiviral immune response and are also associated with autoimmunity. Several CTLs have been investigated in crustaceans, primarily with respect to their function in the immune response. In this study, we cloned a novel CTL gene (LvCTLU) from Litopenaeus vannamei. LvCTLU is involved in microbe agglutination and phagocytosis. Downregulating LvCTLU increased the cumulative mortality of L. vannamei after Vibrio parahemolyticus infection. Similar to other reported CTLs, LvCTLU also had antiviral properties. Downregulation of LvCTLU also increased the cumulative mortality of L. vannamei after infection with white spot syndrome virus. More importantly, LvCTLU expression was induced by the unfolded protein response (UPR), which is the key pathway in the endoplasmic reticulum (ER)-stress response of eukaryotic organism. Our results suggested that this protein might be involved in the shrimp ER-stress response. Reporter gene assay indicated that LvCTLU was regulated by X-box-binding protein 1, which is the key transcription factor in the UPR. Our study thus revealed that LvCTLU plays vital roles in both the anti-pathogen immune response and the ER-stress response.
C 型凝集素（CTLs）以 Ca2+依赖的方式结合碳水化合物，参与许多细胞活动，尤其是免疫。CTLs 在抗菌和抗病毒免疫反应中都起着重要作用，并且与自身免疫有关。已经在甲壳动物中研究了几种 CTLs，主要是研究它们在免疫反应中的功能。在本研究中，我们从凡纳滨对虾中克隆了一种新的 CTL 基因（LvCTLU）。LvCTLU 参与微生物的凝集和吞噬作用。下调 LvCTLU 后，凡纳滨对虾在副溶血弧菌感染后的累积死亡率增加。与其他报道的 CTLs 相似，LvCTLU 也具有抗病毒特性。下调 LvCTLU 后，凡纳滨对虾在感染白斑综合征病毒后的累积死亡率也增加。更重要的是，LvCTLU 的表达受未折叠蛋白反应（UPR）的诱导，UPR 是真核生物内质网（ER）应激反应的关键途径。我们的结果表明，该蛋白可能参与虾的 ER 应激反应。报告基因试验表明，LvCTLU 受 X 盒结合蛋白 1（UPR 中的关键转录因子）的调控。因此，我们的研究表明 LvCTLU 在抗病原体免疫反应和 ER 应激反应中都起着至关重要的作用。
