Orthomyxoviruses: Molecular Biology

Influenza viruses are enveloped viruses with a segmented, single-stranded, negative-sense RNA genome. They attach to host cells via their major surface glycoprotein, hemagglutinin, and are internalized in endocytic compartments. Fusion of the viral membrane with that of the endosome results in the release of the encapsidated viral genome. Viral replication and transcription take place in the nucleus of the infected cell and newly synthesized proteins and viral RNA then assemble at the plasma membrane for packaging into budding virus particles. The ability to manipulate the genome of influenza virus through the advent of reverse genetics has greatly enhanced our understanding of this medically important virus.