Functional analysis of the Cystatin F gene response to SGIV infection in orange-spotted grouper, Epinephelus coioides.

Abstract

Cystatin F (CyF), an inhibitor of cysteine protease, was widely studied in immune defense and cancer therapy. However, the function of CyF and its latent molecular mechanism during virus infection in fish remain vacant. In our research, we cloned the open reading frame (ORF) of CyF homology from orange-spotted grouper (Ec-CyF) consisting of 342 nucleotides and encoding a 114-amino acid protein. Ec-CyF included two cystatins family sequences containing one KXVXG sequence without the signal peptide, and a hairpin ring containing proline and tryptophan (PW). Tissue distribution analysis indicated that Ec-CyF was highly expressed in spleen and head kidney. Besides, further analysis showed that the expression of Ec-CyF increased during SGIV infection in grouper spleen (GS) cells. Subcellular localization assay demonstrated that Ec-CyF was mainly distributed in cytoplasm in GS cells. Overexpressed Ec-CyF demoted the mRNA level of viral genes MCP, VP19 and LITAF. Meanwhile, SGIV-induced apoptosis in fat head minnow (FHM) cells was impeded, as well as the restraint of caspase 3/7 and caspase 8. In addition, Ec-CyF overexpression up-regulated the expression of IFN related molecules including ISG15, IFN, IFP35, IRF3, IRF7, MYD88 and down-regulated proinflammatory factors such as IL-1β, IL-8 and TNF-α. At the same time, Ec-CyF-overexpressing increased the activity of IFN3 and ISRE promoter, but impeded NF-κB promoter activity by luciferase reporter gene assay. In summary, our findings suggested that Ec-CyF was involved in innate immunity response and played a key role in DNA virus infection.

• Authors: Suifeng Xu, Yuexuan Wang, Chengzong Han, Yunxiang Jiang, Qiwei Qin, Shina Wei
• Journal: Fish & shellfish immunology (Fish Shellfish Immunol) Vol. 130 Pg. 43-52 (Nov 2022) ISSN: 1095-9947 [Electronic] England
• PMID: 36084885 (Publication Type: Journal Article)
• Copyright: Copyright © 2022 Elsevier Ltd. All rights reserved.

Chemical References

• Fish Proteins
• Interleukin-8
• Myeloid Differentiation Factor 88
• NF-kappa B
• Nucleotides
• Protein Sorting Signals
• RNA, Messenger
• Tumor Necrosis Factor-alpha
• Tryptophan
• Proline
• Caspase 3
• Caspase 8

Topics

• Amino Acid Sequence
• Animals
• Bass
• Caspase 3 (genetics)
• Caspase 8 (genetics)
• DNA Virus Infections
• Fish Diseases
• Fish Proteins (chemistry)
• Immunity, Innate (genetics)
• Interleukin-8 (genetics)
• Myeloid Differentiation Factor 88 (genetics)
• NF-kappa B (metabolism)
• Nucleotides (metabolism)
• Phylogeny
• Proline (genetics, metabolism)
• Protein Sorting Signals (genetics)
• RNA, Messenger (metabolism)
• Tryptophan (metabolism)
• Tumor Necrosis Factor-alpha (genetics)