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Wang Y, Xu X, Zhang A, Yang S, Li H. Role of alternative splicing in fish immunity. FISH & SHELLFISH IMMUNOLOGY 2024; 149:109601. [PMID: 38701992 DOI: 10.1016/j.fsi.2024.109601] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 04/22/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Alternative splicing serves as a pivotal source of complexity in the transcriptome and proteome, selectively connecting various coding elements to generate a diverse array of mRNAs. This process encodes multiple proteins with either similar or distinct functions, contributing significantly to the intricacies of cellular processes. The role of alternative splicing in mammalian immunity has been well studied. Remarkably, the immune system of fish shares substantial similarities with that of humans, and alternative splicing also emerges as a key player in the immune processes of fish. In this review, we offer an overview of alternative splicing and its associated functions in the immune processes of fish, and summarize the research progress on alternative splicing in the fish immunity. Furthermore, we review the impact of alternative splicing on the fish immune system's response to external stimuli. Finally, we present our perspectives on future directions in this field. Our aim is to provide valuable insights for the future investigations into the role of alternative splicing in immunity.
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Affiliation(s)
- Yunchao Wang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Xinyi Xu
- Hunan Fisheries Science Institute, Changsha, 410153, China
| | - Ailong Zhang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China
| | - Shuaiqi Yang
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China.
| | - Hongyan Li
- College of Marine Life Sciences, and Institute of Evolution & Marine Biodiversity, Ocean University of China, Qingdao, 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266003, China.
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Tang Y, Lv X, Liu X, Song J, Wu Y, Zhou Q, Zhu R. Three IRF4 paralogs act as negative regulators of type Ⅰ IFN responses in yellow catfish (Pelteobagrus fulvidraco). FISH & SHELLFISH IMMUNOLOGY 2022; 131:537-548. [PMID: 36243274 DOI: 10.1016/j.fsi.2022.10.016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2022] [Revised: 09/14/2022] [Accepted: 10/09/2022] [Indexed: 06/16/2023]
Abstract
IRF4 is a master member of the interferon regulatory factor (IRF) family playing vital regulatory roles in immune system development and function. Tetrapods have a single-copy IRF4 gene, while teleosts harbor duplicated IRF4 genes. This work describes three IRF4 paralogs from yellow catfish (Pelteobagrus fulvidraco), designated PfIRF4A, PfIRF4B and PfIRF4B-like. These genes all contain a typical IRF structural architecture. Phylogenic and synteny analyses indicate that they should arise from the teleost-specific whole-genome duplication. PfIRF4 genes are abundantly expressed in the immune-related tissues and upregulated by PolyI:C, LPS, and Edwardsiella ictaluri. Ectopic expression of these genes inhibits the activation of fish type Ⅰ IFN promoters and downregulates the transcription levels of IFN-responsive genes, thus allowing the efficient replication of a fish rhabdovirus, spring viremia of carp virus (SVCV). PfIRF4s possess a repressive effect on MyD88-mediated activation of IFN and NF-κB. Some differences are observed between each individual paralog. PfIRF4B is the main form expressed across the tissues and the most up-regulated one after pathogen induction. It exerts a stronger inhibitory effect on IFN antiviral response than the other two paralogs. PfIRF4A and PfIRF4B-like are primarily present in the nucleus, while PfIRF4B displays colocalization and direct associations with MyD88 in the cytoplasm. Overall, the data demonstrate that three PfIRF4 paralogs show shared and individual functional properties in the negative regulation of type Ⅰ IFN response.
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Affiliation(s)
- Yuhan Tang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China
| | - Xue Lv
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China
| | - Xiaoxiao Liu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China
| | - Jingjing Song
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China
| | - Yeqing Wu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China
| | - Qi Zhou
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China
| | - Rong Zhu
- State Key Laboratory of Biocatalysis and Enzyme Engineering, School of Life Sciences, Hubei University, Wuhan, Hubei, 430062, China.
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Zhu Y, Yang G. Molecular identification and functional characterization of IRF4 from common carp (Cyprinus carpio. L) in immune response: a negative regulator in the IFN and NF-κB signalling pathways. BMC Vet Res 2022; 18:106. [PMID: 35300694 PMCID: PMC8928632 DOI: 10.1186/s12917-022-03205-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2022] [Accepted: 03/07/2022] [Indexed: 12/03/2022] Open
Abstract
Background The interferon (IFN) regulatory factors (IRFs) were originally identified as transcription factors playing critical roles in the regulation of IFN-related genes in the signal pathway. In mammals, IRF4 plays a vital role in both the innate and adaptive immune system. This study aims to reveal the molecular characterization, phylogenetic analysis, expression profiles and the regulatory role in the IFN and NF-κB signalling pathways of IRF4 in common carp (Cyprinus carpio. L) (abbreviation, ccIRF4). Results Here, ccIRF4 was identified and characterized, it contained a DNA binding domain (DBD) which possess five tryptophans and an IRF-associated domain (IAD). The predicted protein sequence of the ccIRF4 showed higher identities with grass carp (Ctenopharyngodon idella) and zebrafish (Danio rerio). Phylogenetic analysis suggested that ccIRF4 has the closest relationship with zebrafish IRF4. Quantitative real-time PCR analysis showed that ccIRF4 was constitutively expressed in all investigated tissues with the highest expression level in the gonad. Polyinosinic:polycytidylic acid (poly I:C) stimulation up-regulated the ccIRF4 expressions in the liver, spleen, head kidney, skin, foregut and hindgut. Upon Aeromonas hydrophila injection, the expression level of ccIRF4 was up-regulated in all tissues with the exception of spleen. In addition, ccIRF4 was induced by lipopolysaccharide (LPS), peptidoglycan (PGN) and Flagellin in head kidney leukocytes (HKLs). Overexpression of the ccIRF4 gene in epithelioma papulosum cyprini cells (EPC) down regulated the expressions of IFN-related genes and proinflammatory factors. Dual-luciferase reporter assay revealed that ccIRF4 decreased the activation of NF-κB through MyD88. Conclusions These results indicate that ccIRF4 participates in both antiviral and antibacterial immune response and negatively regulates the IFN and NF-κB response. Overall, our study on ccIRF4 provides more new insights into the innate immune system of common carp as well as a theoretical basis for investigating the pathogenesis and prevention of fish disease.
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Affiliation(s)
- Yaoyao Zhu
- Key Laboratory of Tropical Marine Fishery Resources Protection and Utilization of Hainan Province, College of Fisheries and Life Science, Hainan Tropical Ocean University, No. 1 Yucai Road, Sanya, 572022, China. .,Hainan Key Laboratory for Conservation and Utilization of Tropical Marine Fishery Resources, Hainan Tropical Ocean University, Sanya, 572022, China.
| | - Guiwen Yang
- Shandong Provincial Key Laboratory of Animal Resistance Biology, College of Life Sciences, Shandong Normal University, No. 88 East Wenhua Road, Jinan, 250014, China.
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Gao FX, Lu WJ, Shi Y, Zhou L, Gui JF, Zhao Z. Identification and functional characterization of three irf7 transcript variants in obscure puffer (Takifugu obscurus). DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2021; 119:104019. [PMID: 33482241 DOI: 10.1016/j.dci.2021.104019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2020] [Revised: 01/13/2021] [Accepted: 01/13/2021] [Indexed: 06/12/2023]
Abstract
Interferon regulatory factor 7 (IRF7) is a key mediator in regulating the type Ι IFN response. Although irf7 has been identified in more than twenty fish species, alternative splicing has not been found in teleost irf7. Alternative splicing is an important mechanism expanding the transcriptomic and proteomic diversity, and has been found in several IRF family members. Here, three alternative splicing variants of irf7 were identified and characterized in obscure puffer. The first splicing transcript (Toirf7v1) was predicted to encode 428 amino acids with a DNA-binding domain (DBD), an interaction-associated domain (IAD) and a serine-rich domain (SRD). Toirf7v2 encoded 430 amino acids caused by the intron retention, and contained the whole conserved domains. Toirf7v3 encoded a truncated protein with 337 amino acids resulting from the alternative 5' splice-site selection, and lacked part of IAD domain and the entire SRD domain. Functional studies demonstrated that all of the three isoforms could activate the expression of type I IFN and IFN-stimulated genes (ISGs). Nevertheless, the two variants (Toirf7v2 and Toirf7v3) exhibited much less ability to induce transcription of IFN and ISGs compared to the Toirf7v1. Our findings suggest that these splicing variants may have distinct roles in the regulation of immune response. These results will be beneficial to understand the functional characteristics of irf7 variants in fish.
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Affiliation(s)
- Fan-Xiang Gao
- Department of Marine Biology, College of Oceanography, Hohai University, Nanjing, 210098, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Wei-Jia Lu
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Yan Shi
- Department of Marine Biology, College of Oceanography, Hohai University, Nanjing, 210098, China
| | - Li Zhou
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Jian-Fang Gui
- Department of Marine Biology, College of Oceanography, Hohai University, Nanjing, 210098, China; State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072, China
| | - Zhe Zhao
- Department of Marine Biology, College of Oceanography, Hohai University, Nanjing, 210098, China.
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