Download RNA dependent synthesis of DNA and RNA

RNA dependent synthesis of DNA and RNA
RNA-dependent RNA polymerase (RDRP), or RNA replicase, is an enzyme that catalyzes the replication of
RNA from an RNA template. This is in contrast to a typical RNA polymerase, which catalyzes the
transcription of RNA from a DNA template.
Viral RDRPs were discovered in the early 1960s from studies on Mengovirus and polio virus when it was
observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA directed
RNA synthesis. This lack of sensitivity suggested that there was a virus specific enzyme that could copy
RNA from an RNA template and not from a DNA template.
The most famous example of RDRP is the polio virus. The virus is made up of RNA which enters the cell
through receptor-mediated endocytosis. From there, the RNA is able to act as a template for
complementary RNA synthesis, immediately. The complementary strand is then, itself, able to act as a
template for the production of new viral genomes which are further packaged and released from the cell
ready to infect more host cells. The advantage of this method of replication is that there is no DNA stage,
replication is quick and easy. The disadvantage is that there is no 'back-up' DNA copy.
Eukaryotes also have RDRPs involved in RNA interference; these amplify micro RNAs and small temporal
RNAs and produce double-stranded RNA using small interfering RNAs as primers
Reverse transcription is the process of making a double stranded DNA (deoxyribonucleic acid) molecule
from a single stranded RNA (ribonucleic acid) template. It is called reverse transcription as it acts in the
opposite or reverse direction to transcription .In 1970 Howard Temin and David Baltimore independently
discovered the enzyme responsible for reverse transcription, named reverse transcriptase, the possibility
that genetic information could be passed on in this mannerRNA dependent synthesis of DNA and RNA
RNA synthesis
RNA-dependent RNA polymerase (RDRP), or RNA replicase, is an enzyme that catalyzes the replication of
RNA from an RNA template. This is in contrast to a typical RNA polymerase, which catalyzes the
transcription of RNA from a DNA template.
Viral RDRPs were discovered in the early 1960s from studies on Mengovirus and polio virus when it was
observed that these viruses were not sensitive to actinomycin D, a drug that inhibits cellular DNA directed
RNA synthesis. This lack of sensitivity suggested that there was a virus specific enzyme that could copy
RNA from an RNA template and not from a DNA template.
The most famous example of RDRP is the polio virus. The virus is made up of RNA which enters the cell
through receptor-mediated endocytosis. From there, the RNA is able to act as a template for
complementary RNA synthesis, immediately. The complementary strand is then, itself, able to act as a
template for the production of new viral genomes which are further packaged and released from the cell
ready to infect more host cells. The advantage of this method of replication is that there is no DNA stage,
replication is quick and easy. The disadvantage is that there is no 'back-up' DNA copy.
Eukaryotes also have RDRPs involved in RNA interference; these amplify micro RNAs and small temporal
RNAs and produce double-stranded RNA using small interfering RNAs as primers
Reverse transcription is the process of making a double stranded DNA (deoxyribonucleic acid) molecule from a
single stranded RNA (ribonucleic acid) template. It is called reverse transcription as it acts in the opposite or
reverse direction to transcription .In 1970 Howard Temin and David Baltimore independently discovered the
enzyme responsible for reverse transcription, named reverse transcriptase, the possibility that genetic information
could be passed on in this manner