Atlantic salmon IPS-1 mediates induction of IFNa1 and activation of NF-κB and localizes to mitochondria

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.…”

“…Interestingly, among tissues examined, pufferfish MAVS is most abundant in muscle and liver [27], where flounder MAVS expression is weakest [26]. In response to stimuli, flounder MAVS does not respond either to VSHV in the tissue of kidney, or to poly (I:C) and VSHV in the cultured kidney leukocytes [26]; salmon MAVS is not induced in cultured TO cells by IFN and ISAV [25]. However, MAVS transcripts of grass carp and common carp are upregulated in cultured fish cells or some tissues in response to GCRV infection [37,38].…”

“…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].…”

“…For example, overexpression of salmon RIG-I or rainbow trout MDA5 results in upregulation of IFN and ISGs and also establish host antiviral states [21,22]; ectopic expression of crucian carp IRF3 or MITA triggers the expression of both IFN and ISGs [23,24]. 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].…”

Identification and characterization of MAVS from black carp Mylopharyngodon piceus

“…MAVS is located on the outer membrane of mitochondria through its TM domain and its CARD domain interacts with the CARD domain of RIG-I and MDA5 when virus derived RNA is recognized by these two sensors [22,23]. MAVS is activated upon association with RIG-I and MDA5 and result in activation of IRF-3/7 and NF-kB, which lead to the induction of type I IFNs and IFN-stimulated genes (ISGs) [24,25].…”