MoBio Mechanism of Reverse Transcription Chapter 4

After the RNA retrovirus enters a host cell, its genomic RNA will be transcribed into a double stranded DNA and then integrated into the host DNA. The RNA to DNA transcription is called reverse transcription.

Image
Image

Figure 4-J-1. Mechanism of reverse transcription. The entire process is catalyzed by reverse transcriptase which has both DNA polymerase and RNase H activities.

  1. A retrovirus-specific cellular tRNA hybridizes with a complementary region called the primer-binding site (PBS).
  2. A DNA segment is extended from tRNA based on the sequence of the retroviral genomic RNA.
  3. The viral R and U5 sequences are removed by RNase H.
  4. First jump: DNA hybridizes with the remaining R sequence at the 3' end.
  5. A DNA strand is extended from the 3' end.
  6. Most viral RNA is removed by RNase H.
  7. A second DNA strand is extended from the viral RNA.
  8. Both tRNA and the remaining viral RNA are removed by RNase H.
  9. Second jump: The PBS region of the second strand hybridizes with the PBS region of the first strand.
  10. Extension on both DNA strands. LTR stands for "long terminal repeat".