Search

Alternative splicing is an important basic mechanism for eukaryotes to control gene expression. Different forms of alternative splicing may lead to the production of protein subtypes with different functions, leading to the expansion of protein diversity in organisms, affecting cell production and metabolism, and is even related to the occurrence of many diseases. Many studies have shown that ferritin is usually associated with inflammation, vascular proliferation, and tumors, which is the focus of immunological research. It not only plays a role in iron metabolism and storage in the body, but also plays an important regulatory role in pathways related to immune and inflammatory regulation. However, there are few studies on alternative splicing events of the ferritin gene nowadays. Therefore, this study identified three different splicing isoforms in its ferritin gene fthl27 of Miichthys miiuy through Sanger sequencing, qRT-PCR, and other experimental techniques, and we found that three different splicing isoforms of the ferritin gene fthl27 in M. Miiuy cells showed an upregulation trend after being stimulated by Lipopolysaccharide (LPS) and poly (I: C). The experiment also found that the three isoforms may have different regulatory effects on the expression of inflammatory factors and antiviral immune factors, playing an important role in the innate immune response of fish., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The development of sequencing technology has further accelerated the research of noncoding RNA (ncRNA). A large number of studies have shown that long noncoding RNA (lncRNA) in ncRNA can regulate gene expression in various ways and then affect various physiological and biochemical processes of the host. In this study, we found a novel lncRNA in Miichthys miiuy, named LTCONS6801, which is beneficial to TANK-binding kinase 1 (TBK1) and its mediated pathway to promote the host immune function. First, we found that lncRNA LTCONS6801 can enhance cell activity through cell viability detection and cell proliferation detection. Besides, after poly (I: C) stimulation, overexpression of lncRNA LTCONS6801 promoted the expression of antiviral gene and TBK1. We found that lncRNA LTCONS6801 further affects NF-κB and IRF3 signaling pathways by regulating the expression of TBK1. In short, lncRNA LTCONS6801 is an lncRNA that can positively regulate the host innate immune response by regulating the expression of TBK1. Our study enriches the theory and insight of lncRNA regulating antiviral immune pathway and clarifies the important role of lncRNA in antiviral immunity of teleost fish., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Methyltransferase (METTL3), the most important N6-methyladenosine (m6A) writer, plays a vital role in regulating immune-related signaling pathways. However, the underlying mechanism of METTL3 action remains largely unknown, especially in lower vertebrates. The results of this study show that METTL3 inhibits innate immune response and promotes the infection of miiuy croaker, Miichthys miiuy, by Siniperca chuatsi rhabdovirus and Vibrio anguillarum. Significantly, the function of METTL3 in inhibiting immunity depends on its methylase activity. Mechanistically, METTL3 increases the methylation level of trif and myd88 mRNA, rendering them sensitive to degradation by the YTHDF2/3 reader proteins. By contrast, we found that the YTHDF1 reader protein promotes the translation of myd88 mRNA. In summary, these results indicate that METTL3-mediated m6A modification of trif and myd88 mRNAs suppresses innate immunity by inhibiting the TLR pathway, unveiling a molecular mechanism by which RNA methylation controls innate immunity to pathogens in the teleost fish., (Copyright © 2023 by The American Association of Immunologists, Inc.)

Noncoding RNA (ncRNA) is an important regulatory factor that plays a major role in innate immunity. However, most studies on ncRNA have focused on mammals, resulting in a knowledge gap on ncRNA in lower vertebrates such as teleost fish. In this study, we identified a new long noncoding RNA (lncRNA), termed TAK1-related lncRNA (TARL), which can play a positive role in the antibacterial immunity of Miichthys miiuy to Vibrio anguillarum and V. harveyi. We also found a novel microRNA miR-2188-3p that could target TAK1 and inhibit the host antibacterial response and promote bacterial escape. We further found that the antibacterial effect inhibited by miR-2188-3p could be reversed with TARL. Moreover, V. anguillarum and V. harveyi are the two most susceptible Gram-negative pathogens of aquaculture fish, and the economic losses caused by these two bacteria are immeasurable every year. This study is the first to report on the ability of lncRNA to prevent the escape of V. anguillarum and V. harveyi in fish through the competing endogenous RNA (ceRNA) mechanism. Our results not only elucidate the ceRNA mechanism of the lncRNA in antibacterial immune responses but also provide new insights into the impact of lncRNA on host immunity and bacterial escape., (© 2023. Science China Press.)

In recent years, many studies have shown that long non-coding RNAs (lncRNAs) can regulate many biochemical processes, such as cell growth, proliferation, and immune response, which have attracted great attention. There are relatively many studies on lncRNA in mammals, while the research on lncRNA in lower vertebrates has just begun. In this study, we found a lncRNA, lncRNA LTCONS8875, related to innate immune response in Miichthys miiuy (miiuy croaker). Our results showed that lncRNA LTCONS8875 can up-regulate the expression of IRAK4 at the mRNA and protein levels, and significantly increase the production of inflammatory factors under LPS stimulation. Our research also confirmed that lncRNA LTCONS8875 plays an active role in regulating inflammation, cell proliferation, and cell viability. In summary, this research results showed that lncRNA LTCONS8875 can as an active regulatory role of innate immunity in miiuy croaker by up-regulating the expression of IRAK4, providing some insights for understanding the network mechanism of non-coding regulation of fish immunity., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Fusion gene is a new gene formed by the fusion of all or part of the sequences of two genes, it is caused by chromosome translocation, middle deletion or chromosome inversion. Numerous studies in the past have continuously shown that gene fusions are tightly associated with the occurrence and development of various diseases, especially cancer. Many fusion genes have been identified in humans. However, few fusion genes have been identified in fish. In this study, a novel NLRC3-NLRP12 fusion gene was identified in the Miichthys miiuy (miiuy croaker) by quantitative real-time PCR (qRT-PCR), PCR, and Sanger sequencing. This fusion gene is fused by two genes related to NLRs (nucleotide binding domain and oligomerization domain like receptors). We found that the expression of the NLRC3-NLRP12 fusion gene was significantly upregulated after infection with Vibrio anguillarum (V. anguillarum) or stimulation with lipopolysaccharide (LPS). In addition, the NLRC3-NLRP12 fusion gene was strongly induced by V. anguillarum infection, peaking within the kidney and liver at 12 h post infection. Further functional experiments showed that overexpression of NLRC3-NLRP12 significantly inhibited nuclear factor kappa-B (NF-κB) activation. This study suggests that the newly discovered NLRC3-NLRP12 fusion genes may play an important role in innate immunity in miiuy croaker., (Copyright © 2023. Published by Elsevier Ltd.)

In recent years, more and more researchers have devoted to the study of circular RNAs (circRNAs) in noncoding RNAs. As an important regulator in a variety of biological processes, circRNAs are relatively abundant in the study of mammals, while research in lower vertebrates is still lacking. In this study, we found a circRNA, circPlce1, related to innate immune response in Miichthys miiuy (miiuy croaker). The experimental results confirmed that circPlce1 could promote the production of antiviral genes and inflammatory response under the stimulation of poly (I: C) and LPS. We also confirmed that circPlce1 can promote NF-κB and IRF3 pathways through luciferase reporter assay experiment. In addition, we also found that circPlce1 can promote cell proliferation and improve cell viability. In conclusion, our results showed that circPlce1 plays an active role in regulating inflammatory response, cell proliferation and cell viability, providing a foundation for the study of the biological function of circRNAs in the innate immune response in teleost fish., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

As a non-coding RNA with regulatory functions, microRNAs(miRNAs) can regulate gene expression and participate in a variety of physiological and pathological processes. In recent years, although there have been many studies on miRNA, the regulation mechanisms of miRNA in teleost fish have not been fully elucidated. In this study, it was first predicted that MITA is the target of miR-27c through bioinformatics, and it was confirmed by dual fluorescence experiments. Then we found that miR-27c can inhibit the expression of MITA at the mRNA and protein levels, thereby promoting the NF-κB or IRF3 pathway. It is speculated that miR-27c plays an important role in the innate immunity of teleost fish. This study will help to further understand miRNAs regulatory mechanism in teleost fish., (Copyright © 2022. Published by Elsevier Ltd.)

With the further study of long noncoding RNAs (lncRNAs), an increasing number of biological studies have demonstrated that lncRNAs are involved in various physiological processes, including cell proliferation, apoptosis, invasion, development and disease states. However, unlike mammals, little is known about the role of lncRNAs in the innate immunity of teleost fish. Here, we identify a lncRNA, named LTCONS5539, as critical role in the antiviral and antibacterial response of miiuy croaker and the results showed that lncRNA LTCONS5539 plays a critical regulatory role on TRAF6. Firstly, we found that LPS and poly(I:C) can up-regulate the expression of lncRNA LTCONS5539. Elevated lncRNA LTCONS5539 is capable of increasing the production of inflammatory factors and antiviral genes. Furthermore, the over-expression of lncRNA LTCONS5539 increases the expression of TRAF6 which was confirmed by qPCR and western blotting. On these foundations, we also proved that lncRNA LTCONS5539 modulates innate immunity through TRAF6-mediated immune responses through dual luciferase reporter assay. These results will help to further understand the immunomodulatory mechanisms of lncRNA in teleost fish., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Accumulated studies have shown that long non-coding RNA (lncRNA) is considered a critical regulatory factor in mammals, with a length greater than 200 nucleotides, and it can participate in gene imprinting, dose compensation, transcription enhancement, and antisense regulation. Most of the above studies are carried out in mammals, and there are very few studies on lncRNA of lower vertebrates. Here, we report a novel lncRNA, LTCONS7822, which can play a positive regulatory effect on antiviral immunity in miiuy croaker, Miichthys miiuy. Our results show that the levels of lncRNA LTCONS7822 were significantly increased after poly (I:C) stimulation. Further study, we found that lncRNA LTCONS7822 could positively regulate MITA at the post-transcriptional level. In addition, the dual-luciferase reporter assay analysis showed that the positive regulatory effect of lncRNA LTCONS7822 on NF-κB and IRF3 signaling pathways presented the dose and time-dependent manner. Western blotting experiments proved that lncRNA LTCONS7822 has a positive regulatory effect on MITA. Collectively, our study provided new information to enrich the immune regulation network of lncRNA in teleost fish., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

MicroRNAs (miRNA) are non-coding RNAs that regulate many biochemical processes, such as cell growth, proliferation and immune responses. In this study, we investigated miR-144 as a regulator of IκBα that promotes the activation of NF-κB signaling pathway. And IκBα interact with p65 blocks nuclear translocation of NF-κB and anchors NF-κB in cytoplasmic quiescent cells in an inactive form. The seed region of miR-144 can regulate gene expression by binding to the 3' UTR of IκBα and repress IκBα expression at the post-transcriptional level. More importantly, miR-144 can promote the activation of p65 by inhibiting IκBα, thus affecting the NF-κB signaling pathway. Thus, preventing excessive inflammatory responses from causing autoimmune diseases will help to further understand the immunoregulatory mechanisms of miRNAs in fish after invasion by pathogens., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Long noncoding RNAs (lncRNAs) function as micro regulators to impact gene expression after multiple pathogen infections, which have been largely studied in the last few years. Although lncRNA studies on lower vertebrates have received less attention than those on mammals, current studies suggest that lncRNA plays an important role in the immune response of fish to pathogen infections. Here, we studied the effect of MIR122HG as the host gene of miR-122 and indirectly negatively regulate MAVS-mediated antiviral immune responses in miiuy croaker ( Miichthys miiuy ). We found that poly(I:C) significantly increases the host MIR122HG expression. The increased MIR122HG expression inhibited the production of the antiviral immune-related genes IFN-1, ISG15 and Viperin upon SCRV treatment. In addition, MIR122HG can act as a pivotally negative regulator involved in the MAVS-mediated NF-κB and IRF3 signaling pathways, which can effectively avoid an excessive immune response. Additionally, we found that MIR122HG can promote the replication of SCRV. Our study provides evidence about the involvement of lncRNAs in the antiviral immune response of fish and broadens the understanding of the function of lncRNAs as a precursor miRNA in teleost fish.

Long noncoding RNAs (lncRNAs) are a diverse subset of RNA species of noncoding transcripts that are usually longer than 200 nt. However, the biological role and function of many lncRNAs have not been fully identified. It has been shown that one potential function of lncRNAs is to act as a precursor miRNA and promote the production of multiple miRNAs. However, the function of the miiuy croaker lncRNA MIR122HG has not been explored. In the present study, we show that this differentially expressed teleost fish lncRNA can act as the host gene of miR-122-5p, regulate its expression, and indirectly regulate the expression of potential inflammatory target protein transforming growth factor-β-activated kinase 1. We show that MIR122HG can negatively regulate the transforming growth factor-β-activated kinase 1-triggered NF-κB and interferon regulatory factor 3 signaling pathways and subsequently attenuate the innate immune response. In addition, MIR122HG can promote the replication of Siniperca chuatsi rhabdovirus and exacerbate the pathological effects caused by viral infection. We conclude that the study of lncRNA-miRNA-mRNA interaction through bioinformatics analysis or experimental-supported analysis can provide information for further elucidation of the functions of fish lncRNAs in innate immunity., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2022 The Authors. Published by Elsevier Inc. All rights reserved.)

The inhibitory protein IκBα plays a key role in the inflammatory process and immune response by regulating the activity of the transcription factor NF-κB. microRNA (miR) is a small non-coding RNA that can regulate many biochemical processes, such as cell growth, proliferation, and immune response. In this study, it was first predicted that IκBα is the target of miR-122 through bioinformatics, and it was confirmed by dual fluorescence experiments. Then we found that miR-122 can inhibit the expression of IκBα at the mRNA and protein levels, thereby promoting the p65-activated NF-κB pathway. It is speculated that miR-122 plays an important role in the innate immunity of teleost fish. This study will help to further understand miRNAs regulatory mechanism in teleost fish., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

microRNAs (miRNAs), a crucial class of small non-coding RNA species, have been extensively studied as key molecular in immune regulation in the past decades. Here, we discover a new miRNA miR-148-1-5p and we elaborate that miR-148-1-5p functions as a negative regulator to participate in innate immune responses. In this article, it has been researched that the regulation effect of miR-148-1-5p to the nuclear factor kappaB (NF-κB) signaling pathway by targeting IRAK1 in miiuy croaker. First, through bioinformatics software to predict the potential targets of miR-148-1-5p, we found that IRAK1 had a base complementary region with indicated miRNA. Next, the dual-luciferase assays revealed that overexpression of miR-148-1-5p mimics and pre-miR-148 plasmid could significantly inhibit the luciferase activity of wild-type IRAK1-3'UTR. However, miR-148-1-5p inhibitors attenuated the inhibition caused by miR-148-1-5p. In addition, we also confirmed that miR-148-1-5p could suppress the expression of IRAK1 at mRNA level. Collectively, the regulations of miR-148-1-5p to NF-κB signaling pathways via targeting the IRAK1 gene was studied in miiuy croaker, which provided new information to enrich the immune regulation network of miRNA in teleost fish., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Growing numbers of studies have shown that circular RNAs (circRNAs) can function as regulatory factors to regulate the innate immune response, cell proliferation, cell migration, and other important processes in mammals. However, the function and regulatory mechanism of circRNAs in lower vertebrates are still unclear. Here, we discovered a novel circRNA derived from the gene encoding Bcl-2-like protein 1 (BCL2L1) gene, named circBCL2L1, which was related to the innate immune responses in teleost fish. Results indicated that circBCL2L1 played essential roles in host antiviral immunity and antibacterial immunity. Our study also identified a microRNA, miR-30c-3-3p, which could inhibit the innate immune response by targeting inflammatory mediator TRAF6. And TRAF6 is a key signal transduction factor in innate immune response mediated by TLRs. Moreover, we also found that the antiviral and antibacterial effects inhibited by miR-30c-3-3p could be reversed with the expression of circBCL2L1. Our data revealed that circBCL2L1 functioned as a competing endogenous RNA (ceRNA) of TRAF6 by competing for binding with miR-30c-3-3p, leading to activation of the NF-κB/IRF3 inflammatory pathway and then enhancing the innate immune responses. Our results suggest that circRNAs can play an important role in the innate immune response of teleost fish., Competing Interests: Conflict of interest The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Viral infection induces the initiation of antiviral effectors and cytokines which are critical mediators of innate antiviral responses. The critical molecular determinants are responsible for triggering an appropriate immune response. Long noncoding RNAs (lncRNAs) have emerged as new gene modulators involved in various biological processes, while how lncRNAs operate in lower vertebrates are still unknown. Here, we discover a long noncoding RNA, termed antiviral-associated long noncoding RNA (AANCR), as a novel regulator for innate antiviral responses in teleost fish. The results indicate that fish MITA plays an essential role in host antiviral responses and inhibition of Siniperca chuatsi rhabdovirus (SCRV) production. miR-210 reduces MITA expression and suppress MITA-mediated antiviral responses, which may help viruses evade host antiviral responses. Further, AANCR functions as a competing endogenous RNA (ceRNA) for miR-210 to control protein abundance of MITA, thereby inhibiting SCRV replication and promoting antiviral responses. Our data not only shed new light on understanding the function role of lncRNA in biological processes in teleost fish, but confirmed the hypothesis that ceRNA networks exist widely in vertebrates.

Innate immune response is an important response mechanism for the host to achieve self-protection, and it plays an important role in identifying pathogens and resisting pathogen invasion. Growing evidences have shown that microRNA functions as a crucial regulator involved in the host innate immune response. In this study, the regulations of miR-1388-5p to regulate NF-κB signaling pathways via targeting the IRAK1 gene was studied in miiuy croaker. First, through bioinformatics software prediction, we found that IRAK1 is the direct target of miR-1388-5p, and then the prediction results were verified by using dual-luciferase assays. Next, we found that both miR-1388-5p mimics and pre-miR-1388 plasmids inhibit IRAK1 expression by complementing the seed sequence in the 3'-untranslated region (3'-UTR) of IRAK1. Finally, we observed that miR-1388-5p could negatively regulate NF-κB pathways through targeting IRAK1. These results provide new insights into the function of miR-1388-5p in fish innate immunity, meanwhile enriching miRNA-mediated regulatory networks., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

The innate immune response is first line of host defense against pathogen invasion. However, excessive activation of immune responses may cause autoimmune diseases and excessive inflammation. Retinoic acid-inducible gene I (RIG-I) is an important cytoplasmic pathogen recognition receptor that is activated on virus infection. TNF-receptor-associated factor 6 (TRAF6) plays an essential role in the RIG-I-mediated signaling pathway. MicroRNAs (miRNAs) are noncoding RNAs that are emerging as important regulators of immune responses. In this study, we found that the overexpression of miR-489 mimics and pre-miR-489 significantly suppressed the luciferase activity of the wild-type TRAF6 3'UTR, whereas mutant-type led to a complete abrogation of the negative effect. In addition, we also observed that miR-489 can negatively regulate TRAF6 at the level of translation. More importantly, we demonstrated that miR-489 is a negative regulator of TRAF6 involved in the immune response to poly(I:C) stimulation. These common findings indicated that miR-489 plays a regulatory role in host-virus interactions by targeting TRAF6. Overall, all of the present results provide direct evidence that miR-489 is involved in the regulation of TRAF6 expression in miiuy croaker, which will help to better understand the complex regulatory networks of teleost fish., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

As is known to all, the production of type I interferon (IFN) plays pivotal roles in host innate antiviral immunity, and its moderate production play a positive role in promoting the activation of host innate antiviral immune response. However, the virus will establish a persistent infection model by interfering with the production of IFN, thereby evading the organism inherent antiviral immune response. Therefore, it is of great necessity to research the underlying regulatory mechanisms of type I IFN appropriate production under viral invasion. In this study, we report that a Sp1-responsive miR-15b plays a negative role in siniperca chuatsi rhabdovirus (SCRV)-triggered antiviral response in teleost fish. We found that SCRV could dramatically upregulate miiuy croaker miR-15b expression. Enhanced miR-15b could negatively regulate SCRV-triggered antiviral genes and inflammatory cytokines production by targeting TANK-binding kinase 1 (TBK1), thereby accelerating viral replication. Importantly, we found that miR-15b feedback regulates antiviral innate immune response through NF-κB and IRF3 signaling pathways. These findings highlight that miR-15b plays a crucial role in regulating virus-host interactions, which outlines a new regulation mechanism of fish's innate immune responses., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Chang, Chu, Zheng, Zhang and Xu.)

Increasing evidence shows that the long noncoding RNA (lncRNA) is a major regulator and participates in the regulation of various physiological and pathological processes, such as cell proliferation, differentiation, metastasis, and apoptosis. Unlike mammals, however, the study of lncRNA in lower invertebrates is just beginning and the extent of lncRNA-mediate regulation remains unclear. Here, we for the first time identify an lncRNA, termed nucleotide oligomerization domain 1 (NOD1) antibacterial and antiviral-related lncRNA (NARL), as a key regulator for innate immunity in teleost fish. We found that NOD1 plays an important role in the antibacterial and antiviral process in fish and that the microRNA miR-217-5p inhibits NOD1 expression and thus weakens the NF-κB and the IRF3-driven signaling pathway. Furthermore, our results indicated that NARL functions as a competing endogenous RNA (ceRNA) for miR-217-5p to regulate protein abundance of NOD1; thus, invading microorganisms are eliminated and immune responses are promoted. Our study also demonstrates the regulation mechanism that lncRNA NARL can competitive adsorption miR-217-5p to regulate the miR-217-5p/NOD1 axis is widespread in teleost fish. Taken together, our results reveal that NARL in fish is a critical positive regulator of innate immune responses to viral and bacterial infection by suppressing a feedback to NOD1-NF-κB/IRF3-mediated signaling., Competing Interests: Conflict of interests The authors declare that they have no conflicts of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

Growing pieces of evidence show that the long noncoding RNAs (lncRNAs) as new regulators participate in the regulation of various physiological and pathological processes. The study of lncRNA in lower invertebrates is still unclear compared with that in mammals. Here, we identified a novel lncRNA, termed IRAK4-related lncRNA (IRL), as a key regulator for innate immunity in teleost fish. We find that miR-27c-3p inhibits IRAK4 expression and thus weakens the NF-κB-mediated signaling pathway. Furthermore, the Gram-negative bacterium Vibrio anguillarum and lipopolysaccharide significantly upregulated host lncRNA IRL expression. Results indicate that IRL functions as a competing endogenous RNA for miR-27c-3p to regulate protein abundance of IRAK4; thus, invading microorganisms are eliminated and immune responses are promoted. Our study also demonstrates the regulation mechanism that lncRNA IRL can competitively adsorb miRNA to regulate the miR-27c-3p/IRAK4 axis that is widespread in teleost fish., Competing Interests: Conflict of interest The authors declare that they have no conflict of interest with the contents of this article., (Copyright © 2021 The Authors. Published by Elsevier Inc. All rights reserved.)

NF-κB is a typical transcription factor that regulates expression of various genes involved in inflammatory and immune responses. Therefore, it is essential that NF-κB signaling tightly regulated to maintain immune balance. Compared with those of mammals, the regulatory mechanisms of NF-κB signaling is rarely reported in teleost fish. IκBα is a prominent negative feedback regulator in the NF-κB signaling system. In this study, we determined that IRF11 enhances the inhibitory effect of IκBα on NF-κB activation in teleost fish. Overexpression of IRF11 can inhibit IκBα degradation, whereas its knockdown has the opposite effect of IκBα. Our study further indicates that IκBα was regulated via ubiquitin-proteasome degradation pathway, IRF11 inhibits IκBα in ubiquitin-proteasome degradation. This study provides a novel evidence on the regulation of innate immune signaling pathways in teleost fish and thus provides new insights into the regulatory mechanisms in mammals., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Increasing evidence suggests important roles for long noncoding RNAs (lncRNAs) as new gene modulators involved in various biological processes. However, the function roles of lncRNAs in lower vertebrates are still unknown. Here, we firstly identify a lncRNA, named MAVS antiviral-related lncRNA (MARL), as a key regulator for antiviral immunity in teleost fish. The results indicate that fish MAVS play essential roles in host antiviral responses and inhibition of Siniperca chuatsi rhabdovirus (SCRV) replication. miR-122 reduces MAVS expression and suppress MAVS-mediated antiviral responses, which may help viruses evade host antiviral responses. Further, MARL functions as a competing endogenous RNA (ceRNA) for miR-122 to control protein abundance of MAVS, thereby inhibiting SCRV replication and promoting antiviral responses. Our data not only shed new light on understanding the function role of lncRNA in biological processes in lower vertebrates, but confirmed the hypothesis that ceRNA regulatory networks exist widely in vertebrates., Competing Interests: The authors have declared that no competing interests exist.