Coronavirus

Coronaviruses are enveloped RNA viruses. They cause mild to severe respiratory illness and spread through respiratory droplets.

During infection, the virus binds to host cell surface receptors, fuses its membrane with the host cell membrane, and releases its RNA.

Once inside, cytoplasmic ribosomes translate the viral RNA into polyproteins that contain proteases.

These proteases cleave the polyproteins into different nonstructural proteins.

Some nonstructural proteins cause conformational change in the endoplasmic reticulum, forming double-membrane vesicles.

Other nonstructural proteins form a replication–transcription complex that attaches to these vesicles. Here, viral RNA replicates, and shorter mRNAs are produced that encode viral proteins.

Viral envelope proteins are transported to the ER–Golgi intermediate compartment.

The replicated viral RNA binds to nucleocapsid proteins and moves to the ER–Golgi intermediate compartment, where virion assembly begins.

The newly formed virions travel in vesicles and exit through exocytosis to infect other cells.