Combining mutations in HIV-1 reverse transcriptase with mutations in the HIV-1 polypurine tract affects RNase H cleavages involved in PPT utilization

Virology. 2006 May 10;348(2):378-88. doi: 10.1016/j.virol.2005.12.042. Epub 2006 Feb 10.


The RNase H cleavages that generate and remove the polypurine tract (PPT) primer during retroviral reverse transcription must be specific to generate linear viral DNAs that are suitable substrates for the viral integrase. To determine if specific contacts between reverse transcriptase (RT) and the PPT are a critical factor in determining the cleavage specificity of RNase H, we made HIV-1 viruses containing mutations in RT and the PPT at the locations of critical contacts between the protein and the nucleic acid. The effects on titer and RNase H cleavage suggest that combining mutations in RT with mutations in the PPT affect the structure of the protein of the RT/nucleic acid complex in ways that affect the specificity and the rate of PPT cleavage. In contrast, the mutations in the PPT (alone) and RT (alone) affect the specificity of PPT cleavage but have much less effect on the overall rate of cleavage.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, N.I.H., Intramural

MeSH terms

  • Base Sequence
  • Cell Line
  • DNA, Viral / biosynthesis
  • DNA, Viral / genetics
  • HIV Reverse Transcriptase / chemistry
  • HIV Reverse Transcriptase / genetics*
  • HIV Reverse Transcriptase / metabolism*
  • HIV-1 / genetics*
  • HIV-1 / metabolism*
  • Humans
  • Kinetics
  • Macromolecular Substances
  • Mutagenesis, Site-Directed
  • Mutation*
  • RNA, Viral / chemistry
  • RNA, Viral / genetics*
  • RNA, Viral / metabolism*
  • Ribonuclease H / metabolism*
  • Substrate Specificity
  • Transfection


  • DNA, Viral
  • Macromolecular Substances
  • RNA, Viral
  • HIV Reverse Transcriptase
  • Ribonuclease H