Characterization of the polymerase and RNase H activities of human foamy virus reverse transcriptase

J Virol. 2004 Jun;78(12):6112-21. doi: 10.1128/JVI.78.12.6112-6121.2004.


Foamy virus (FV) replication, while related to that of orthoretroviruses, differs at a number of steps. Several of these differences involve the reverse transcriptase (RT). There appear to be fewer RTs present in FV than in orthoretroviruses; we previously proposed that the polymerase of FV RT was more active than orthoretroviral RTs to compensate for the numerical difference. Here we present further characterization of the RT of FV. The polymerase activity of FV RT was greater than that of human immunodeficiency virus type 1 RT in a variety of assays. We also examined the RNase H activity of FV RT, and we propose that FV RT has a basic loop in the RNase H domain. Although the sequence of the basic loop of FV RT is different from the basic loop of either Moloney leukemia virus RNase H or Escherichia coli RNase H, the FV RT basic loop appears to have a similar function.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • DNA Primers / metabolism
  • DNA, Viral / metabolism
  • Diphosphates / metabolism
  • HIV Reverse Transcriptase / chemistry
  • HIV Reverse Transcriptase / genetics
  • HIV Reverse Transcriptase / metabolism
  • Molecular Sequence Data
  • RNA, Viral / metabolism
  • RNA-Directed DNA Polymerase* / chemistry
  • RNA-Directed DNA Polymerase* / genetics
  • RNA-Directed DNA Polymerase* / metabolism
  • Ribonuclease H* / chemistry
  • Ribonuclease H* / genetics
  • Ribonuclease H* / metabolism
  • Spumavirus / enzymology*
  • Templates, Genetic


  • DNA Primers
  • DNA, Viral
  • Diphosphates
  • RNA, Viral
  • HIV Reverse Transcriptase
  • RNA-Directed DNA Polymerase
  • Ribonuclease H