reverse transcriptase(redirected from RNA-directed DNA polymerase)
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Any of the deoxyribonucleic acid (DNA) polymerases present in particles of retroviruses which are able to carry out DNA synthesis using an RNA template. This reaction is called reverse transcription since it is the opposite of the usual transcription reaction, which involves RNA synthesis using a DNA template. See Retrovirus
The transfer of genetic information from RNA to DNA in retrovirus replication was proposed in 1964 by H. M. Temin in the DNA provirus hypothesis for the replication of Rous sarcoma virus, an avian retrovirus which causes tumors in chickens and transformation of cells in culture, and reverse transcriptase has since been purified from virions of many retroviruses. The avian, murine, and human retrovirus DNA polymerases have been extensively studied.
Studies indicate that reverse transcriptase is widely distributed in living organisms and that all reverse transcriptases are evolutionarily related. For example, the organization of the nucleotide sequence of integrated retroviral DNA has a remarkable resemblance to the structure of bacterial transposable elements, in particular, transposons.
Reverse transcriptase genes are present in the eukaryotic organisms in retrotransposons and in retroposons or long interspersed (LINE) elements. Both of these types of elements can transpose in cells. See Deoxyribonucleic acid (DNA), Ribonucleic acid (RNA), Transposons