IKKε-like plays an important role in the innate immune signaling of the Pacific oyster (Crassostrea gigas). Issue 93 (October 2019)

• Record Type: Journal Article
• Authors: Huang, Baoyu; Tang, Xueying; Zhang, Linlin; Li, Li; Wang, Wei; Liu, Mingkun; Zhang, Guofan
• Is Part Of: Fish & shellfish immunology. Issue 93(2019)
• Page Start: 551
• Page End: 558
• Publication Date: 2019-10
• Subjects: Oyster -- Innate immunity -- IKKε -- TBK1 -- NF-κB -- IRF; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2019.07.074
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: IκB-related kinase ε (IKKε) plays a crucial role in the activation of nuclear factor κB (NF-κB) by phosphorylating inhibitor of NF-κB (IκB) and in the regulation of interferon (IFN) gene expression by phosphorylating IFN regulatory factors (IRFs). In this study, we cloned an IKKε homologue cDNA (designated as CgIKKε-like ) from the Pacific oyster, Crassostrea gigas . The full 2896-bp cDNA sequence comprised a 2163-bp open reading frame (ORF) encoding 720 amino acids. CgIKKε-like is ubiquitously expressed, and its mRNA levels in hemocytes after poly I:C, V. alginolyticus, or OsHV-1 μVar challenge were analyzed by real-time PCR. Compared to that in the control, CgIKKε-like mRNA expression levels were significantly increased at 3 h and peaked at 6 h after OsHV-1 μVar challenge; no obvious changes were observed in expression levels until 24 h after either V. alginolyticus or poly I:C challenge, reaching a maximum at 24 h ( p < 0.01) and then rapidly decreasing. CgIKKε-like transfection into human cell lines induced NF-κB and ISRE activation, while transfection with CgIKKε-like deletion mutants abolished NF-κB and ISRE reporter gene activation. Additionally, CgIKKε-like could interact with CgTBK1 and could form homodimers strongly, which may be critical for the immune signaling transduction. Last but not least, we found that CgIKKε-like may increase CgIκBs phosphorylation and could interact with CgIRF8. Together, these results suggest that CgIKKε-like could respond to pathogenic infection, participate in the immune signal transduction and activate NF-κB and ISRE reporter genes. Thus, CgIKKε-like could play an important role in the oyster immune system. Highlights: An IKKε-like gene was identified in the Pacific oyster Crassostrea gigas. CgIKKε-like mRNA expression was induced after viral and bacterial challenge. CgIKKε-like could induce NF-κB and ISRE activation in human cell lines. CgIKKε-like interacts with CgTBK1 and forms homodimers strongly. CgIKKε-like interacts with CgIRF8 and may phosphorylate CgIκBs.