
In the absence of RIG-I, vertebrates have evolved MDA5 to recognize 5'ppp-RNA viruses, while viruses have developed m6A-mediated strategies to degrade MDA5 and evade host immunity.


coremsg

The incessant arms race between viruses and hosts has led to numerous evolutionary innovations that shape life’s evolution. During this process, the interactions between viral receptors and viruses have garnered significant interest since viral receptors are cell surface proteins exploited by viruses to initiate infection. Our study sheds light on the arms race between the MDA5 receptor and 5’ppp-RNA virus in a lower vertebrate fish, M. miiuy . Firstly, the frequent and independent loss events of RIG-I in vertebrates prompted us to search for alternative immune substitutes, with homology-dependent genetic compensation response (HDGCR) being the main pathway. Our further analysis suggested that MDA5 of M. miiuy and G. gallus , the homolog of RIG-I, can replace RIG-I in recognizing 5’ppp-RNA virus, which may lead to redundancy of RIG-I and loss from the species genome during evolution. Secondly, as an adversarial strategy, 5’ppp-RNA SCRV can utilize the m6A methylation mechanism to degrade MDA5 and weaken its antiviral immune ability, thus promoting its own replication and immune evasion. In summary, our study provides a snapshot into the interaction and coevolution between vertebrate and virus, offering valuable perspectives on the ecological and evolutionary factors that contribute to the diversity of the immune system.

### Competing Interest Statement

The authors have declared no competing interest.

An arms race between 5’ppp-RNA virus and its alternative recognition receptor MDA5 in RIG-I-lost teleost fish

evolutionary-arms-race-between-vertebrates-and-5-ppp-rna-viruses-the-role-of-mda5-in-compensating-for-rig-i-deficiency


Evolutionary Arms Race Between Vertebrates and 5'ppp-RNA Viruses: The Role of MDA5 in Compensating for RIG-I Deficiency
