Mutation of the catalytic domain of the foamy virus reverse transcriptase leads to loss of processivity and infectivity.
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.
Rinke
Carolyn S
CS
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA.
Boyer
Paul L
PL
Sullivan
Mark D
MD
Hughes
Stephen H
SH
Linial
Maxine L
ML
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
D011994:Recombinant Proteins; D018894:Reverse Transcriptase Inhibitors; D054303:HIV Reverse Transcriptase; D012194:RNA-Directed DNA Polymerase