To utilize the cellular machinery, viral mRNAs must contain control signals which are recognized by the cell, e.g. ribosome-binding sites, splice signals, polyadenylation signals. Similarly, some DNA viruses, e.g. Papovaviruses, encode a protein which binds to the origin of replication and stimulates cellular DNA polymerase to replicate the virus genome. During this process, the basic structure of the virus is formed. In the cytoplasm. On the inner surface of the cell membrane.
Enveloped viruses acquire the lipid membrane as the virus buds out through the cell membrane.
Virion envelope proteins are picked up during this process as the virus is extruded. The stage of the life-cycle at which the virus becomes infectious. Usually involves structural changes in the particle, often resulting from specific cleavage of capsid proteins to form the mature products, which frequently leads to a conformational change in the capsid, or the condensation of nucleoproteins with the genome. For some viruses, assembly and maturation are inseparable, whereas for others, maturation may occur after the virus particle has left the cell. To view a video animation of HIV replication, click here .