viruses inhibiting NMD

(pmid: 30297408 2018) Past studies have revealed various types of interactions be-tween viruses and the NMD pathway (39). Genomic-wide siRNAscreening for host factors involved in the replication of Semlikiforest virus (SFV), an alphavirus, in mammalian cells (16) and agenetic screen inArabidopsisfor factors involved in the repli-cation of Potato virus X (PVX), a positive-strand RNA virus inplants (13), led to the discovery of the role of NMD factors in thereplication of these cytoplasmic RNA viruses. Like CoVs, theseviruses carry a single-stranded, positive-sense RNA genome witha long 3′UTR and produce one or more subgenomic mRNAsthat form a nested-set structure in infected cells. In the case ofretroviruses, the viral mRNAs are synthesized in the nucleus andmany of them undergo splicing; therefore, it is not surprising thatretroviruses have evolved to control the NMD pathway. Roussarcoma virus, an avian retrovirus, carries an RNA stability el-ement that facilitates the escape of full-length viral RNA (car-rying a long 3′UTR) from degradation by the NMD pathway(40). Human T-lymphotropic virus type I encodes the NMDinhibitors Tax and Rex, which prolong the half-life of viralmRNAs (41, 42), whereas the NMD factor UPF1 serves as apositive regulator of HIV type 1 replication (43–45).

mechanisms of NMD inhibition

(pmid: 30297408 2018) The core protein of hepatitis C virus (HCV) binds to anEJC recycling factor and prevents the factor from interactingwith other components of the EJC, leading to the inhibition ofthe NMD pathway in infected cells (17).