Cell Transformation By RNA Tumour Viruses Flashcards
Which type of viruses were first used in the study of how viruses induced mutation and transformed the cell?
DNA viruses (which were the easiest to study)
Which RNA virus was used to study cell transformation?
RSV
Describe Watson and Crick’s dogma on the flow of Genetic information
Genetic information goes from DNA —> RNA —> Proteins.
Why did the genetic information dogma pose an obstical in Howard temin’s work?
He was studying how RSV transformed cells. And RSV was an RNA virus. At the time it was known that DNA viruses transformed cells by integrating their genetic info into the host genome, but how could an RNA virus do this? Since this was not how Genetic information flowed
Temin postulated that RSV makes a copy of itself as a DNA virus, describe his experiment that led him to this conclusion.
Temin looked at virus production in controlled culture and in culture with antinomycin D - which is an antibiotic that blocks DNA transcription.
In the culture with the antibiotic which blocks DNA transcription, viral particle production was also blocked. This was concentration dependant.
Based on this result, Temin hypothesised that RVS transforms cells bacause it makes a copy of itself as a DNA virus. This ‘pro-virus’ then becomes integrated into the genome
How did Temin finally prove that RSV makes a DNA copy of itself?
He dismatled the virus and purified the proteins from it.
From this he found an RNA dependant DNA polymerase - essentially a reverse transcriptase. Hence RSV had the machinery for pro-virus synthesis.
He then established how the virus was integrated
In which year was it proved without any doubt that RSV duplicated and integrated into the host genome just like SV40
1974
It was clear that tumours were produced by certain viruses through their ability to ______ in a stable manner into the host _________
Integrate ; genome
