The ER in Replication of Positive-Strand RNA Viruses

Ritzenthaler, Christophe; Elamawi, Rabab

All eukaryotic positive-sense single-strand RNA viruses, (+)ssRNA, replicate their genome in associationwith membranes of host cells. The presence of a replicating virus frequently induces proliferationand rearrangement of the host membranes into various cytopathic structures, including invaginations, vesicles,spherules or membranous webs. Such structures are considered to be virus-induced organelles specializedin replication functions. Virtually all membranes are able to be rearranged to support replication. Thus,membranes from peroxisomes, endosomes, lysosomes, vacuoles, mitochondria, and chloroplasts are used for(+)ssRNA virus replication, but the endoplasmic reticulum (ER) is by far the preferred organelle. The specifictype of membrane system utilized in assembling the viral replication complex is strictly dependent on individualviruses and is likely to be genetically determined. The various molecular interactions that govern ER targetingof plant viruses highlight how viruses can exploit the diversity of interactions that occurs between proteinsand membrane or lipid structures.