Newcastle disease virus induces stable formation of bona fide stress granules to facilitate viral replication through manipulating host protein translation

Mammalian cells respond to various environmental stressors to form stress granules (SGs) by arresting cytoplasmic mRNA, protein translation element, and RNA binding proteins. Virus-induced SGs function in different ways, depending on the species of virus; however, themechanismofSGregulation of virus replication is not well understood. In this study, Newcastle disease virus (NDV) triggered stable formation of bona fide SGs on HeLa cells through activating the protein kinase R (PKR)/eIF2a pathway. NDV-induced SGs contained classic SGmarkers T-cell internal antigen (TIA)(-1), RasGTPase-activatingprotein-binding protein (G3BP)(-1), eukaryotic initiation factors, andsmall ribosomal subunit, which could be disassembled in the presence of cycloheximide. Treatment with nocodazole, amicrotubule disruptiondrug, led to the formation of relatively small and circular granules, indicating that NDV infection induces canonical SGs. Furthermore, the role of SGs on NDV replication was investigated by knockdown of TIA(-1) and TIA(-1)-related (TIAR) protein, the 2 critical components involved in SG formation from the HeLa cells, followed by NDV infection. Results showed that depletion of TIA-1 orTIARinhibitedviral protein synthesis, reducedextracellularvirus yields, but increasedglobal protein translation. FISH revealed that NDV-induced SGs contained predominantly cellular mRNA rather than viral mRNA. Deletion of TIA(-1) or TIAR reduced NP mRNA levels in polysomes. These results demonstrate that NDV triggers stable formationofbonafideSGs, whichbenefit viralprotein translation andvirus replicationbyarresting cellularmRNA.-Sun, Y., Dong, L., Yu, S., Wang, X., Zheng, H., Zhang, P., Meng, C., Zhan, Y., Tan, L., Song, C., Qiu, X., Wang, G., Liao, Y., Ding, C. Newcastle disease virus induces stable formation of bona fide stress granules to facilitate viral replication through manipulating host protein translation.