title: Isolation, characterization, and genetic complementation of a cellular mutant resistant to retroviral infection.
abstract: 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.
authors.affiliation: Department of Genetics, Cell Biology, and Development, University of Minnesota, 420 Delaware Street, SE, Minneapolis, MN 55455, USA.
authors.forename: Sumit
authors.initials: S
authors.lastname: Agarwal
authors.forename: Josephine
authors.initials: J
authors.lastname: Harada
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Schreifels
authors.forename: Patrycja
authors.initials: P
authors.lastname: Lech
authors.forename: Bryan
authors.initials: B
authors.lastname: Nikolai
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Yamaguchi
authors.forename: Sumit K
authors.initials: SK
authors.lastname: Chanda
authors.forename: Nikunj V
authors.initials: NV
authors.lastname: Somia
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002460:Cell Line; D049109:Cell Proliferation; D002469:Cell Separation / Q000379:methods*; D003001:Cloning, Molecular; D005822:Genetic Vectors / Q000235:genetics; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D016089:Immunodeficiency Virus, Feline / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D009052:Leukemia Virus, Murine / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism; D007976:Leupeptins / Q000494:pharmacology; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011480:Protease Inhibitors / Q000494:pharmacology; D011991:Receptors, Virus / Q000378:metabolism; D012192:Retroviridae Infections / Q000235:genetics* / Q000378:metabolism / Q000473:pathology / Q000821:virology; D016415:Sequence Alignment; D017386:Sequence Homology, Amino Acid
chemical_list: D007976:Leupeptins; D011480:Protease Inhibitors; D011991:Receptors, Virus; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde