Download BIOL 161 10F - Heartland Community College

“The Discovery of Reverse Transcriptase”
November 2, 2010
Biology 161
Dr. Hong Fei
By: David Meyer
Kylene Wolfe
Ryan Schramer
Adrian Bachman
History
Genetic information was demonstrated
through the transfer of information of the
biological system during the years of:
1940's, 1950's & 1960's
In 1970 more of a focus on RNA tumor
viruses but left many unanswered
questions.
Howard Temin
Studied RNA tumor
viruses most of his life
His early days he spent
time working on Rous
sarcoma virus (RSV)
Temin was the one that
came up with the first
hypothesis for the
study of Reverse
Transcriptase
Howard Temin Hypothesis
“The RNA genome of RSV is
converted into a DNA provirus.”
Howard Temin Proposal
“RSV is sensitive to inhibitors of
DNA synthesis and suggesting that
DNA, complementary to the RSV
genomic RNA, is present in
transformed cells.”
David Baltimore
Spent time studying virus
replication
He looked at RNA and
DNA at a more
biochemical view looking
deep within individual
virions
He later focused on RNA
tumor viruses and
concluded with Rauscher
murine leukemia virus
(R-MLV)
Howard Temin and David Baltimore
walked two different pathways
Experiment Time!
They disrupted their pure stock viruses by
using nonionic detergents
“Can a retrovirus perform DNA synthesis?”
Then “radiolabeled deoxthymidine
triphosphate (dTTP) along with three
deoxynucleotide triphosphates (dATP, dCTP,
dGTP) to the virion preparation.”
Did these reactions contain any incorporation of
radioactive dTTP into DNA?
YES!
Each experiment, dTTP turned into nucleic acid
They tested their experiment by adding
enzymes reacted with RNA or DNA
Results:
Sensitive to Dnase
One more question?
“What was the template?”
One more test!
Baltimore and Temin both
“preincubated the virions with
RNase, which catalyzes the
degradation of RNA into
ribonucleotide monophosphates.”
Results:
The longer the pretreatment of
virions with RNase, the lower the
amount of DNA-synthesizing activity,
- thus an enzyme in the virion could
catalyze RNA-dependent DNA
synthesis.”
“
Results/Data
Demonstration of RNA-dependent DNA Synthesis
Radioactive Tymidine Incorporated into Nucleic Acid
Experimental Treatment:
R-MLV
RSV
Standard Conditions
Virions pretreated with RNase
3.69 pmol
0.52 pmol
9110 dpm
2650 dpm
Untreated Product
After product is treated with RNase
After Product is treated with Dnase
1425 dpm
1361 dpm
125 dpm
8350 dpm
7200 dpm
1520 dpm
This was reverse to what normally was
happened in DNA and RNA giving it's name:
“Reverse Transcriptase”
Conclusion:
Temin believed that his hypothesis was true
all along he just had to prove it to the world
Baltimore believed a different theory but
tested Temin theory by checking RNAdependent and DNA polymerization.
What has this done to help the
world?
Concert mRNA to DNA help create cDNA
libraries
coloning and study of tissues
study of many genes throughout biology
Explosion of research in retroviruses/ RNA
viruses

Temin/Baltimore Future
Since HIV-AIDS is a retrovirus!
This drove Temin and Baltimore to a
Noble Prize in 1975
QUIZ TIME!!!
1. Why was the research done?
a. Win a Noble prize
b. Become president
c. To test whether or not RNA genome of RSV
is converted into a DNA provirus
d. Test Michael Jackson's DNA
Question 2
2. What method did these men use?
a. Newton's Law method
b. Broke down a virus and started doing
DNA/RNA test on it
c. Dr. Fei Method
d. Heartland College Education Method
Question 3
3. With the results was this
experiment successful?
a. YES!
b. No
c. Maybe
d. Not sure
Question 4
4. What could you conclude from
this experiment?
a. It was the worlds greatest experiment
b. The longer the pretreatment of virions with
RNase, the lower the amount of DNA-synthesizing
activity, - thus an enzyme in the virion could catalyze
RNA-dependent DNA synthesis.”
c. If water goes up, it must come back down
d. DNA/RNA is the same in all people
Question 5
5. What is one way this research
has helped the world?
a. It helped two men win a Noble Prize
b. It's going to save the world
c. It gave a cure to AIDS
d. Explosion of research in retroviruses/ RNA
viruses
Bonus Question
Who is the greatest Biology
instructor in the who world?
a. Dr. Hong Fei
b. President Obama
c. Rod Blagojevich
d. Police Officer
The End!