Replication of Viruses Infecting Eukaryotes

Abstract

Viruses are biological entities incapable of existing in a cell‐independent manner. Viruses infecting eukaryotic cells offer all possibilities of genome composition, being either DNA or RNA, single‐stranded or double‐stranded, circular or linear, segmented or non‐segmented. Therefore, viruses have evolved a variety of replication strategies to convert viral genome information into infectious viral particles. Furthermore, gene expression strategies affecting replication, transcription, translation, signalling or macromolecular trafficking, have evolved to exploit and subvert the cellular machinery. The cellular response to virus infection is dependent on the gene expression strategies exploited by the different type of viruses. Conversely, to counteract the cellular antiviral response, viruses have developed sophisticated mechanisms leading to a large heterogeneity in the nature of virus‐host interactions. Their study is providing key information for designing strategies of virus control. At the same time, viruses are useful molecular tools to delineate the mechanisms behind basic cellular processes. Key Concepts: Capsid: A protein shell comprising the main structural unit of a virus particle. Matrix protein: A structural protein of a virus particle that underlies the envelope and links it to the core. Monocistronic: A messenger RNA that encodes a single protein. Negative strand: The group of RNA viruses whose genome contains the reverse polarity of the messenger RNA. Nucleocapsid: The core of a virus particle consisting of the genome plus a complex of proteins. Polyprotein: A long polypeptide encoding several mature proteins that are subsequently released by protease cleavage. Positive strand: The group of RNA viruses whose genome contains the same polarity as the messenger RNA. Receptor: A molecule on the surface of a cell that is used by a virus for attachment. Segmented genome: The group of viruses with the genome packaged in the capsid split into two or more molecules. Uncoating: The stage of viral replication at which structural proteins are disassembled and the virus genome is exposed to the replication machinery.