The basic loop of the RNase H domain of MLV RT is important both for RNase H and for polymerase activity

Virology. 2001 Mar 30;282(1):206-13. doi: 10.1006/viro.2000.0827.


Escherichia coli RNase H has a basic extension that is involved in binding nucleic acid substrates. This basic extension is present in the RNase H of Moloney murine leukemia virus reverse transcriptase (MLV RT), but has been deleted from the RNase H of HIV-1 RT. Previous work showed that removing the basic loop from MLV RT (the mutant is called DeltaC) blocked viral replication; however, DeltaC MLV RT retained RNase H activity in an in situ gel assay. We prepared recombinant DeltaC MLV RT and compared its activity to wild-type MLV RT. The DeltaC mutant is impaired in both polymerase and RNase H activity; the pattern of defects suggests that the basic loop is involved in the binding of MLV RT to a heteropolymeric template-primer.

Publication types

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

MeSH terms

  • Animals
  • Catalytic Domain*
  • DNA-Directed DNA Polymerase / genetics*
  • DNA-Directed DNA Polymerase / metabolism
  • Mice
  • Moloney murine leukemia virus / enzymology*
  • Mutation
  • RNA-Directed DNA Polymerase / genetics*
  • RNA-Directed DNA Polymerase / metabolism
  • Recombinant Proteins / metabolism
  • Ribonuclease H / genetics*
  • Ribonuclease H / metabolism


  • Recombinant Proteins
  • RNA-Directed DNA Polymerase
  • DNA-Directed DNA Polymerase
  • Ribonuclease H