Isolation, characterization, and genetic complementation of a cellular mutant resistant to retroviral infection

Proc Natl Acad Sci U S A. 2006 Oct 24;103(43):15933-8. doi: 10.1073/pnas.0602674103. Epub 2006 Oct 16.


By using a genetic screen, we have isolated a mammalian cell line that is resistant to infection by retroviruses that are derived from the murine leukemia virus, human immunodeficiency virus type 1, and feline immunodeficiency virus. We demonstrate that the cell line is genetically recessive for the resistance, and hence it is lacking a factor enabling infection by retroviruses. The block to infection is early in the life cycle, at the poorly understood uncoating stage. We implicate the proteasome at uncoating by completely rescuing the resistant phenotype with the proteasomal inhibitor MG-132. We further report on the complementation cloning of a gene (MRI, modulator of retrovirus infection) that can also act to reverse the inhibition of infection in the mutant cell line. These data implicate a role for the proteasome during uncoating, and they suggest that MRI is a regulator of this activity. Finally, we reconcile our findings and other published data to suggest a model for the involvement of the proteasome in the early phase of the retroviral life cycle.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Cell Line
  • Cell Proliferation
  • Cell Separation / methods*
  • Cloning, Molecular
  • Genetic Vectors / genetics
  • HIV-1 / drug effects
  • HIV-1 / genetics*
  • HIV-1 / metabolism
  • Humans
  • Immunodeficiency Virus, Feline / drug effects
  • Immunodeficiency Virus, Feline / genetics*
  • Immunodeficiency Virus, Feline / metabolism
  • Leukemia Virus, Murine / drug effects
  • Leukemia Virus, Murine / genetics*
  • Leukemia Virus, Murine / metabolism
  • Leupeptins / pharmacology
  • Male
  • Molecular Sequence Data
  • Mutation / genetics
  • Phenotype
  • Protease Inhibitors / pharmacology
  • Receptors, Virus / metabolism
  • Retroviridae Infections / genetics*
  • Retroviridae Infections / metabolism
  • Retroviridae Infections / pathology
  • Retroviridae Infections / virology
  • Sequence Alignment
  • Sequence Homology, Amino Acid


  • Leupeptins
  • Protease Inhibitors
  • Receptors, Virus
  • benzyloxycarbonylleucyl-leucyl-leucine aldehyde