Special Features of Reoviral Molecular Biology
Replication
Replication of reoviruses occurs in the cytoplasm, and reoviruses package an RNA dependent RNA polymerase into their virion. Moreover, replication and transcription occur in partially uncoated virions. This may be a viral mechanism to avoid detection by TLR receptors of the innate immune system that detect dsRNA.
Leaky Scanning
Some reoviral genomes produce mRNA transcripts that undergo leaky scanning. In leaky scanning, the ribosome can skip an upstream start codon and continue scanning the transcript for a subsequent start codon. In this manner, start codons may be in different frames, generating a mechnaism for differential gene expression.
Having multiple reading frames per transcript increases the diversity of protein products the virus can synthesize.
Reassortment
Orthoreoviruses are believed to undergo reassortment if cells become co-infected with two compatable strains of orthoreoviruses. This is similar to the antigenic shift that influenza undergoes.