Programmed cell death 4 (PDCD4) in mammals, a gene closely associated with apoptosis, is involved in many biological processes, such as cell aging, differentiation, regulation of cell cycle, and inflammatory response. In this study, grouper Epinephelus coioides PDCD4, EcPDCD4-1 and EcPDCD4-2, were obtained. The open reading frame (ORF) of EcPDCD4-1 is 1413 bp encoding 470 amino acids with a molecular mass of 52.39 kDa and a theoretical pI of 5.33. The ORF of EcPDCD4-2 is 1410 bp encoding 469 amino acids with a molecular mass of 52.29 kDa and a theoretical pI of 5.29. Both EcPDCD4-1 and EcPDCD4-2 proteins contain two conserved MA3 domains, and their mRNA were detected in all eight tissues of E. coioides by quantitative real-time PCR (qRT-PCR) with the highest expression in liver. The expressions of two EcPDCD4s were significantly up-regulated after Singapore grouper iridovirus (SGIV) or Vibrio alginolyticus infection. In addition, over-expression of EcPDCD4-1 or EcPDCD4-2 can inhibit the activity of the nuclear factor-κB (NF-κB) and activator protein-1 (AP-1), and regulate SGIV-induced apoptosis. The results demonstrated that EcPDCD4s might play important roles in E. coioides tissues during pathogen-caused inflammation.

哺乳动物程序性细胞死亡 4 (PDCD4) 是一种与细胞凋亡密切相关的基因，它参与了许多生物学过程，如细胞衰老、分化、细胞周期调节和炎症反应。本研究获得石斑石斑鱼PDCD4、EcPDCD4-1和EcPDCD4-2。EcPDCD4-1 的开放阅读框 (ORF) 为 1413 bp，编码 470 个氨基酸，分子量为 52.39 kDa，理论 pI 为 5.33。EcPDCD4-2的ORF为1410 bp，编码469个氨基酸，分子量为52.29 kDa，理论pI为5.29。EcPDCD4-1 和 EcPDCD4-2 蛋白均含有两个保守的 MA3 结构域，并且在E. coioides的所有八种组织中都检测到了它们的 mRNA通过定量实时 PCR (qRT-PCR) 在肝脏中表达最高。新加坡石斑鱼虹彩病毒（SGIV）或溶藻弧菌感染后两种EcPDCD4s的表达显着上调。此外，EcPDCD4-1 或 EcPDCD4-2 的过表达可抑制核因子-κB (NF-κB) 和激活蛋白-1 (AP-1) 的活性，并调节 SGIV 诱导的细胞凋亡。结果表明，EcPDCD4s 可能在病原体引起的炎症过程中在E. coioides组织中发挥重要作用。