Essential role of the D domain of linc000889 in inhibiting avian reovirus replication.

Avian reovirus (ARV) is a double-stranded RNA virus that can cause immunosuppression, irregular bleeding, spleen necrosis, and other symptoms in ducks, posing a serious threat to the poultry industry. Previous studies have confirmed that the duck-derived linc000889 can inhibit ARV replication. In this study, qRT-PCR revealed that linc000889 could promote the expression of interferon-β (IFN-β) and its downstream genes Mx and OASL. Subsequently, using RNA pull-down and protein mass spectrometry, we identified that the host protein NLRX1 associates with the sense strand of linc000889. This binding was verified by RNA immunoprecipitation (RIP) experiments. NLRX1 overexpression and knockdown experiments indicated that NLRX1 negatively regulates IFN-β expression under the conditions tested . Additionally, we found that linc000889 correlates with reduced NLRX1 protein expression. Moreover, NLRX1 complementation experiments suggested that linc000889 promotes IFN-β expression by negatively regulating NLRX1 protein, thereby inhibiting ARV replication. In this study, we also constructed eukaryotic expression plasmids lacking different domains of linc000889. The results showed that the inhibitory effect of the variant lacking the D domain on NLRX1 protein was significantly weakened, suggesting that the D domain is important for the ability for linc000889 to bind to NLRX1. In conclusion, this study confirms that the D domain is important for the ability for linc000889 to regulate NLRX1 protein, promote IFN-β expression, and inhibit ARV replication. This study provides new insights into the role of long noncoding RNAs (lncRNAs) in antiviral immune mechanisms and lays a theoretical foundation for developing lncRNAs-based antiviral strategies.