Vibrio harveyi is regarded as serious pathogen for marine fishes. However, host defense mechanisms involved in V. harveyi infection remain incompletely defined. The transcription factor IFN regulatory factor 7 (IRF7) is largely associated with host defense against viral infections, and the role of IRF7 during V. harveyi infection in fish has not been well illuminated previously. In this study, IRF7 from golden pompano (Trachinotus ovatus) was characterized (TroIRF7). The TroIRF7 gene is 1323 bp, which encodes 440 amino acid residues. Multiple amino acid alignments of TroIRF7 shows 30.37%–80.18% identity with other fish IRF7s, including Epinephelus coioides (80.18%), Larimichthys crocea (79.72%), Collichthys lucidus (79.26%), Miichthys miiuy (79.26%), Channa argus (78.77%), Cynoglossus semilaevis (72.67%), and Gadus morhua (65.23%). Like other IRF7s, TroIRF7 also contains 3 conserved domains: an N-terminal DNA-binding domain (DBD), an IRF association domain (IAD), and a C-terminal serine-rich domain (SRD). In the DBD, 4–5 conserved tryptophans were observed, which is a characteristic unique to all fish IRF7 members. TroIRF7 was constitutively expressed, with high levels in gill, head kidney, spleen, skin, and intestine. V. harveyi infection-induced TroIRF7 transcripts significantly up-regulation and translocation to the nucleus. TroIRF7 overexpression promote the fish to inhibit the replication of V. harveyi. And TroIRF7 knockdown led to decreased bacterial clearance in fish tissue. Furthermore, over-expression of TroIRF7 resulted in an increased production of interferon a3 and IFN signaling molecule in the spleen, suggesting that V. harveyi activates the IRF7– IFN pathway. These results suggest that TroIRF7 is an important component of immune responses against V. harveyi infection.

哈维弧菌被认为是海洋鱼类的严重病原体。然而，参与哈维氏弧菌感染的宿主防御机制仍未完全确定。转录因子 IFN 调节因子 7 (IRF7) 在很大程度上与宿主防御病毒感染有关，而 IRF7在鱼类哈维氏弧菌感染中的作用以前没有得到很好的阐明。在这项研究中，对来自金鲳鱼 ( Trachinotus ovatus ) 的 IRF7 进行了表征 (TroIRF7)。TroIRF7基因全长1323 bp，编码440个氨基酸残基。TroIRF7 的多个氨基酸比对显示与其他鱼类 IRF7 具有 30.37%–80.18% 的同一性，包括Epinephelus coioides (80.18%)、Larimichthys crocea(79.72%)、金鱼草(79.26%)、Miichthys miiuy ( 79.26 %)、鳐鱼(78.77%)、半滑舌鳎(72.67%) 和金鱼草(65.23%)。与其他 IRF7 一样，TroIRF7 也包含 3 个保守结构域：N 端 DNA 结合结构域 (DBD)、IRF 关联结构域 (IAD) 和 C 端富含丝氨酸结构域 (SRD)。在 DBD 中，观察到 4-5 个保守的色氨酸，这是所有鱼类 IRF7 成员独有的特征。TroIRF7 呈组成型表达，在鳃、头肾、脾、皮肤和肠中具有高水平。五、哈维伊感染诱导的 TroIRF7 转录物显着上调并易位至细胞核。TroIRF7过表达促进鱼抑制哈维氏弧菌的复制。并且 TroIRF7 敲低导致鱼组织中的细菌清除率降低。此外，TroIRF7 的过表达导致脾脏中干扰素 a3 和 IFN 信号分子的产生增加，这表明哈维弧菌激活了 IRF7-IFN 通路。这些结果表明 TroIRF7 是针对哈维氏弧菌感染的免疫反应的重要组成部分。