Rous sarcoma virus
is a retrovirus
and is the first oncovirus
to have been described: it causes sarcoma
As with all retroviruses, it reverse transcribes its RNA genome into cDNA
before integration into the host DNA.
was discovered in 1911 by Peyton Rous
, working at Rockefeller University
in New York City, by injecting cell free extract of chicken
tumour into healthy Plymouth Rock chickens.The extract was found to induce oncogenesis
. The tumour was found to be composed of connective tissue (a sarcoma).
Rous was awarded the Nobel Prize
for the significance of his discovery in 1966
Structure and genome
RSV is a class VI enveloped virus with a positive sense RNA genome having a DNA intermediate.
RSV has three genes:
- gag - encodes capsid proteins
- pol - encodes reverse transcriptase
(It lost the env gene normally seen in avian retroviruses during the recombination events that allowed it to acquire src)
The RSV genome has terminal repeats
enabling its integration into the host genome and also overexpression of RSV genes.
The src gene
as it triggers uncontrolled growth in abnormal host cells. It is an acquired gene, found to be present throughout the animal kingdom
with high levels of conservation between species.
The src gene was taken up by RSV and incorporated into its genome
conferring it with the advantage of... Read More