Oncogenes and Model Organisms Flashcards
What was the first animal tumour virus discovered?
RSV (Rous Sarcoma Virus).
What does RSV do?
Causes sarcomas (tumours of connective tissue) in chickens.
What are all animal tumour viruses classified as?
Retroviruses.
What is the genetic material of a retrovirus?
RNA.
How do they replicate in the host?
Through a DNA intermediate, catalyzed by the enzyme reverse transcriptase changing the RNA to DNA.
What happens to the DNA intermediate?
It becomes incorporated into the host’s genome and is then inherited as part of the host’s DNA-may result in tumour.
What do tumour viruses do to host cells?
They transform them.
What is different about this transformed or infected cell?
The cells become insensitive to their crowing neighbours (contact inhibition) and pile up in culture.
What are these piles in culture known as?
Foci. If virus from focus is inserted into animals, tumours may result thus proving the induction ways of a virus.
How did a mutagenesis of RSV help in discovery?
Could mutate the known RSV and then isolate. This helped to determine components of the viruses that no longer transformed host cells but still could replicate.
Where was the mutation of a virus that could replicate but not transform?
The src gene.
What is src DNA closely related to?
A gene in the chicken genome.
What was the first example of an oncogene?
The src gene.
What did Varmus and Bishop receive a Nobel Prize for?
For there discovery of the fact that a viral oncogene is normal constituent (somewhat altered) of the host cells.
What is interesting about this discovery?
The fact that normal host cells harbour genes that can be altered as to cause tumours.
