Coxsackievirus and adenovirus receptor inhibits tilapia lake virus infection via binding to viral segment 8 and 10 encoded protein

Abstract

The global aquaculture industry of tilapia (Oreochromis niloticus) has been significantly impacted by the emergence of tilapia lake virus (TiLV). However, effective prevention and control measures are still not available due to a lack of unclear pathogenesis of TiLV. Our previous transcriptome found that coxsackievirus and adenovirus receptor (CAR) was in response to TiLV infection in tilapia. To explore the potential function of OnCAR, the effect of OnCAR on TiLV proliferation was analyzed in this study. The OnCAR open reading frame (ORF) sequence of tilapia was 516 bp in length that encoded 171 amino acids with an Ig-like domain and transmembrane region. The OnCAR gene showed widespread expression in all investigated tissues, with the highest levels in the heart. Moreover, the OnCAR gene in the liver and muscle of tilapia exhibited dynamic expression levels upon TiLV challenge. Subcellular localization analysis indicated that OnCAR protein was mainly localized on the membrane of tilapia brain (TiB) cells. Importantly, the gene transcripts, genome copy number, S8-encoded protein, cytopathic effect, and internalization of TiLV were obviously decreased in the TiB cells overexpressed with OnCAR, indicating that OnCAR could inhibit TiLV replication. Mechanically, OnCAR could interact with viral S8 and S10-encoded protein. To the best of our knowledge, OnCAR is the first potential anti-TiLV cellular surface molecular receptor discovered for inhibiting TiLV infection. This finding is beneficial for better understanding the antiviral mechanism of tilapia and lays a foundation for establishing effective prevention and control strategies against tilapia lake virus disease (TiLVD).