Provirus
From Wikipedia, the free encyclopedia
A provirus is a virus that has integrated itself into the DNA of a host cell. One kind of virus that can become a provirus is a retrovirus. When a retrovirus invades a cell, the RNA of the retrovirus is transcribed into DNA by reverse transcriptase, then inserted into the host genome by an integrase.
A provirus is not active while integrated into a host genome in this way. Instead, it is passively replicated along with the host genome and passed on to the original cell's offspring; all descendants of the infected cell will also bear proviruses in their genomes. Eventually, in response to changes in the host's environmental conditions or health, the provirus will be activated and begin massive transcription of its viral genome. This results in the destruction of its host as its protein synthesis machinery is hijacked to produce more viruses.
Examples in humans include HIV and HTLV.
A provirus not only refers to a retrovirus but is also used to describe other viruses that can integrate into the host chromosome, another example being adeno-associated virus.
