Characterization of Kruppel-like factor 6 in Epinephelus coioides: The role in viral infection and the transcriptional regulation on Peroxisome proliferator-activated receptor δ. Issue 99 (April 2020)

• Record Type: Journal Article
• Authors: Yang, Min; Wang, Yuxin; Wang, Qing; Zhou, Zhekai; Yu, Yepin; Wei, Shina; Wang, Shaowen; Qin, Qiwei
• Is Part Of: Fish & shellfish immunology. Issue 99(2020)
• Page Start: 9
• Page End: 18
• Publication Date: 2020-04
• Subjects: Kruppel-like factor 6 -- Grouper -- Singapore grouper iridovirus -- Peroxisome proliferator-activated receptor δ -- Promoter activity -- Transcription factor; Fishes -- Immunology -- Periodicals; Shellfish -- Immunology -- Periodicals; Poissons -- Immunologie -- Périodiques; Crustacés -- Immunologie -- Périodiques; 571.9617
• DOI: 10.1016/j.fsi.2020.01.061
• Languages: English
• ISSNs: 1050-4648

Abstract

Abstract: The Kruppel-like factor 6 (KLF6) is a member of Kruppel-like factor family, which belong to the Zinc finger family of transcription factors that mediates various cellular processes, such as proliferation, differentiation, development, and programmed cell death. Peroxisome proliferator-activated receptors (PPARs) are a family of transcription factors belonging to the nuclear receptor superfamily and they regulate numerous genes through ligand-dependent transcriptional activation and repression. In this study, we focus on the role of KLF6 gene in virus infection and the regulation of KLF6 on PPAR-δ in orange-spotted grouper ( Epinephelus coioides ). The ORF sequence of Ec KLF6 was 846 bp, encoding a polypeptide of 282 amino acids with three conserved Zinc finger (type Cys2 -His2 ) domain in the C-terminal region. Basing on the detection of the mRNA levels of viral genes, western blotting of MCP protein, and morphological CPEs, we found that the overexpression of Ec KLF6 suppressed the replication of Singapore grouper iridovirus (SGIV), exerting its antiviral activity against fish virus. Moreover, promoter analysis was performed to investigate whether Ec KLF6 was a regulator of Ec PPAR-δ. The luciferase reporter assay and real time PCR results indicated a negative regulatory role of Ec KLF6 on Ec PPAR-δ transcription in grouper. Further experimental analysis shows that the potential Ec KLF6 binding sites may locate in the Ec PPAR-δ-4-M3 (+133 to +154) and Ec PPAR-δ-4-M4 (+354 to +368) region of the Ec PPAR-δ promoter. Electrophoretic mobile shift assays (EMSAs) verified that Ec KLF6 interacted with the binding site of the Ec PPAR-δ-4-M4 promoter region. In addition, we also found that KLF6 promotes inflammatory responses in GS cells. Considering that KLF6 and PPAR-δ play opposite roles in regulating inflammatory responses, we speculated the promoting effect of KLF6 on inflammatory response may be related to its negative regulation on Ec PPAR-δ. In conclusion, the present study provides the first evidence of the negative regulation of Ec PPAR-δ transcription by Ec KLF6 and contributes to a better understanding of the transcriptional mechanisms of Ec KLF6 in fish. Highlights: We characterized EcKLF6 and illuminated its roles in fish against virus infection. EcKLF6 seems to inhibit SGIV infection in vitro . EcKLF6 could bind to the promoter of EcPPAR-δ and regulate its transcription.