Activation Of Type ? Interferon Pathway Mediated By Goose MAVS And Its Antiviral Effects Evaluation

Pattern recognition receptors(PRR),as an important part of the host cell's innate immune system,can recognize multiple pathogenic microorganisms and rapidly initiate a series of signaling cascades reaction.It plays an important antiviral role in innate immunity by synthesizing cytokines such as type I interferons and inflammatory cytokines.MAVS(Mitochondrial antiviral-signaling protein)is a key adapter protein in the RLR signaling pathway and it is very important to study its regulation of the antiviral effect.In this study,goose MAVS gene(goMAVS)was identified for the first time.The cloned goMAVS was highly homologous to the predicted goMAVS.However,several sequence fragments were absent in the predicted goMAVS.These fragments were then proved to be essential for goMAVS function.GoMAVS plays an antiviral role by activating type I interferon(IFN)pathway in a species-specific manner.The CARD-like domain,transmembrane domain of goMAVS were essential for the activation of type ? IFN pathway.Together,we identified goMAVS as a goose RIG-I(goRIG-I)interactive protein and demonstrated the role of goMAVS in antiviral innate immunity.1 Amplification and analysis of goose MAVS gene sequenceIn this study,we extracted the total RNA in GEF as a template to amplify the goose MAVS gene by overlap PCR.The sequence analysis showed that the goose MAVS gene fragment size was 2019 bp and encodes a total of 673 amino acids.Goose MAVS contains an N-terminal caspase recruitment domain(CARD)-like region(10-77 aa),a proline-rich region(PRR)(103-216 aa),and a C-terminal transmembrane(TM)domain(654-673 aa).The goose MAVS was cloned into the PCMV 3x FLAG 14 vector,and the expressed protein band size was about 72 KD by SDS-PAGE analysis.2 Functional analysis of various domain on goose MAVS gene sequenceThe deletion of CARD domain and TM domain in goose MAVS inhibit downstream ISGs production,indicating that the CARD domain and the TM domain play an important role in the antiviral effect of goose MAVS.Intriguingly,deletion of the PRR domain either did not affect or even up-regulated the mRNA levels of ISGs to some extent.These results reveal the essential role of CARD and TM domains in MAVS-mediated IFN production.3 Effect of goose MAVS against NDV infectionTo investigate the effect of goose MAVS on NDV replication,we overexpressed goose MAVS and then infected NDV in GEF.The mRNA levels of downstream ISGs and viral NP protein were selected as detection targets.In early NDV infection,after overexpression of goose MAVS,the mRNA levels of downstream ISGs significantly increased.And the mRNA levels of viral NP protein significantly decreased.At the late stage of infection,after overexpression of goose MAVS,the mRNA levels of downstream ISGs almost had no change.And the mRNA levels of viral NP protein almost unchanged.These results together indicate that goose MAVS mainly plays its antiviral role at the early stage of NDV infection.