title: Mutation of the catalytic domain of the foamy virus reverse transcriptase leads to loss of processivity and infectivity.
abstract: Foamy virus (FV) replication is resistant to most nucleoside analog reverse transcriptase (RT) inhibitors. In an attempt to create a 2',3'-dideoxy-3'-thiacytidine (3TC)-sensitive virus, the second residue in the highly conserved YXDD motif of simian foamy virus-chimpanzee (human isolate) [SFVcpz(hu)] RT was changed from Val (V) to Met (M). Unexpectedly, the resultant virus, SFVcpz(hu) RT-V313M, replicated poorly, and Met rapidly reverted to Val. Despite the presence of approximately 50% of wild-type RT activity in RT-V313M virions, full-length DNA products were not detected in transfected cells. Using purified recombinant enzymes, we found that the wild-type FV RT is significantly more processive than human immunodeficiency virus type 1 RT. However, the V313M mutant has about 40% of the wild-type level of FV RT activity and has a lower processivity than the wild-type FV enzyme. The V313M mutant RT is also relatively resistant to 3TC. These results suggest that the decrease in RT activity and processivity of FV RT-V313M prevents completion of reverse transcription and greatly diminishes viral replication.
authors.affiliation: Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
authors.forename: Carolyn S
authors.initials: CS
authors.lastname: Rinke
authors.forename: Paul L
authors.initials: PL
authors.lastname: Boyer
authors.forename: Mark D
authors.initials: MD
authors.lastname: Sullivan
authors.forename: Stephen H
authors.initials: SH
authors.lastname: Hughes
authors.forename: Maxine L
authors.initials: ML
authors.lastname: Linial
mesh_terms: D000818:Animals; D020134:Catalytic Domain / Q000235:genetics* / Q000502:physiology; D002460:Cell Line; D006224:Cricetinae; D054303:HIV Reverse Transcriptase / Q000378:metabolism; D006801:Humans; D009154:Mutation; D002679:Pan troglodytes; D012194:RNA-Directed DNA Polymerase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology; D016092:Spumavirus / Q000187:drug effects / Q000201:enzymology* / Q000472:pathogenicity* / Q000502:physiology; D014158:Transcription, Genetic; D014771:Virion / Q000378:metabolism; D014779:Virus Replication
chemical_list: D011994:Recombinant Proteins; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase