Molecular cloning and antiviral activity of IFN-β promoter stimulator-1 (IPS-1) gene in Japanese flounder, Paralichthys olivaceus

Fish MAVS is involved in RLR pathway-mediated IFN response

“…7(A)). Combined with the previous findings in fish [21,23,25,26,28,29,36,40], these results indicate that from fish to mammals, vertebrates have a conserved RLR-triggered IFN antiviral signaling pathway. In this case, the transfected poly(I:C) in CAB cells as cytosolic dsRNA might be recognized by RIG-I, which results in activation of the RIG-I-MAVS-TBK1-IRF3/7 signaling cascade to initiate IFN transcription, and the produced IFN in turn upregulates the expression of ISGs by Jak-Stat pathway, thus establishing host cells antiviral states.…”

“…Fish MAVS genes are first identified from Atlantic salmon (Salmo salar) and zebrafish (Danio rerio), both of which exhibit an ability to induce transcriptional expression of IFN and confer full protection against both RNA and DNA virus on cultured fish cells [21,25]. A similar result is observed when transfection of cultured fish cells with Japanese flounder (Paralichthys olivaceus) MAVS [26]. In addition, overexpression of pufferfish (Tetraodon nigroviridis) MAVS is capable to activate IFN promoter [27]; like mammalian MAVSs, salmon MAVS is a mitochondrial-associated protein in a close vicinity to MITA [21,28].…”

“…Similar to human MAVS [10,44], fish MAVSs are constitutively expressed in all tissues examined [26,27,37,38]. However, inconsistent results are reported about its expression abundance in some tissues.…”

“…Recently MAVS homologous genes have been identified in several fish species, including zebrafish D. rerio [21,28], Japanese flounder P. olivaceus [26], grass carp C. idella [37], common carp Cyprinus carpio [38], and pufferfish T. nigroviridis [27]. These studies have shown that fish MAVS not only activates IFN promoter but also induces the transcription of IFN and some ISGs [21,26,28,39], and that overexpression of fish MAVS confers protection on cultured fish cells against DNA and RNA virus infection [21,26,28]. However, whether fish utilize a conserved signaling pathway involving MAVSmediated IFN response remains elusive.…”

“…However, inconsistent results are reported about its expression abundance in some tissues. For example, grass carp MAVS is most abundant in spleen [37], salmon MAVS in kidney [25], flounder MAVS in head and trunk kidney [26], common carp in liver [38]. Interestingly, among tissues examined, pufferfish MAVS is most abundant in muscle and liver [27], where flounder MAVS expression is weakest [26].…”