Orthoreovirus

Overview

Electron micrograph of Orthoreovirus particles

Orthoreovirus is a genus of viruses within the family Reoviridae. These viruses are non-enveloped and possess a segmented, double-stranded RNA genome. Orthoreoviruses are known to infect a wide range of hosts, including mammals, birds, and reptiles. They are generally not associated with severe disease in humans but can cause mild respiratory or gastrointestinal symptoms.

Structure

Orthoreoviruses are characterized by their icosahedral capsid structure, which is composed of two concentric protein shells. The outer capsid is responsible for the virus's stability and its ability to attach to host cells. The inner capsid contains the viral genome and the RNA-dependent RNA polymerase necessary for replication.

Genome

The genome of Orthoreoviruses is segmented into ten double-stranded RNA segments. Each segment encodes one or more proteins, including structural proteins that form the capsid and non-structural proteins involved in viral replication and assembly. The segmented nature of the genome allows for genetic reassortment, which can lead to the emergence of new viral strains.

Replication Cycle

Orthoreoviruses enter host cells through receptor-mediated endocytosis. Once inside the cell, the outer capsid is removed, and the inner capsid is released into the cytoplasm. The viral RNA-dependent RNA polymerase transcribes the viral RNA segments, leading to the production of viral mRNA. These mRNAs are translated into viral proteins, which assemble into new virions. The newly formed virions are released from the host cell, often causing cell lysis.

Pathogenesis

In humans, Orthoreoviruses are typically associated with mild respiratory or gastrointestinal infections. They are transmitted via the fecal-oral route or through respiratory droplets. In animals, these viruses can cause more severe diseases, depending on the host species and the specific virus strain.

Research and Applications

Orthoreoviruses have been studied extensively as model systems for understanding viral replication and pathogenesis. They are also being explored as potential vectors for gene therapy and oncolytic virotherapy, due to their ability to selectively replicate in and kill cancer cells.

Related Pages

• Reoviridae
• RNA virus
• Viral replication
• Gene therapy