Apoptosis-associated speck-like protein containing a C-terminal caspase recruit domain (ASC) is an important adapter protein in the inflammasome complex that mediates inflammatory caspase activation and host innate immunity in mammals. However, the function of inflammasome components in lower vertebrate remains poorly understood. In this study, full length of SmASC was cloned from turbot (Scophthalmus maximus). Through bioinformatic analysis, we found that SmASC shares relatively high identity with ASC in bony fish. Furthermore, we found that the intact SmASC can form an oligomeric speck-like structure, while the PYD segment of SmASC can form the filamentous structure. Moreover, expression of SmASC was induced after intraperitoneal injection of Edwardsiella piscicida (E. piscicida) in vivo. To further explore the role of SmASC during infection, we constructed SmASC knockdown and overexpression models by administration of siRNA and overexpression plasmids in vivo, respectively. Expression of SmASC decreased the propagation of E. piscicida in different immune organs. In summary, our results characterize the function of SmASC in S. maximus, suggesting that the SmASC plays a critical role in turbot immune responses.

包含C端半胱天冬酶募集结构域（ASC）的与细胞凋亡相关的斑点样蛋白是炎症小体复合物中的重要衔接蛋白，其介导哺乳动物中的炎症半胱天冬酶激活和宿主固有免疫。但是，对低等脊椎动物中炎性体成分的功能仍然知之甚少。在这项研究中，从大菱t（Scophthalmus maximus）克隆了全长的Sm ASC 。通过生物信息学分析，我们发现骨鱼中Sm ASC与ASC具有相对较高的身份。此外，我们发现完整的Sm ASC可以形成寡聚斑点状结构，而Sm ASC的PYD段可以形成丝状结构。而且，Sm的表达体内腹腔注射爱德华氏菌（E. piscicida）后诱发ASC 。为了进一步探讨Sm ASC在感染过程中的作用，我们分别通过在体内施用siRNA和过表达质粒构建了Sm ASC敲低和过表达模型。Sm ASC的表达减少了E. piscicida在不同免疫器官中的繁殖。总之，我们的结果表征了Sm ASC在最大链霉菌中的功能，这表明Sm ASC在大菱in免疫反应中起着关键作用。