title: Mutations in the C-terminal region of the HIV-1 reverse transcriptase and their correlation with drug resistance associated mutations and antiviral treatment.
abstract: OBJECTIVE
  replication of HIV-1 after cell entry is essentially dependent on the reverse transcriptase (RT). Antiretroviral drugs impairing the function of the RT currently aim at the polymerase subunit. One reason for failure of antiretroviral treatment is the evolvement of resistance-associated mutations in the viral genome. For RT inhibitors, almost all identified mutations are located within the polymerase; therefore, general genotyping confines to investigate this subunit. Recently several studies have shown that substitutions within the RNase H and the connection domain increase antiviral drug-resistance in vitro, and some of them are present in patient isolates.
  
  
  OBJECTIVE
  the aim of the present study was to investigate the prevalence of these substitutions and their association with mutations in the polymerase domain arising during antiretroviral treatment.
  
  
  METHODS
  we performed genotypic analyzes on seventy-four virus isolates derived from treated and untreated patients, followed at the HIV Centre of the Johann Wolfgang Goethe University Hospital (Frankfurt/Main, Germany). We subsequently ana?lysed the different substitutions in the c-terminal region to evaluate whether there were associations with each other, n-terminal substitutions or with antiretroviral treatment.
  
  
  RESULTS
  We identified several primer grip substitutions, but almost all of them were located in the connection domain. This is consistent with other in-vivo studies, in which especially the primer grip residues located in the RNase H were unvaried. Furthermore, we identified other substitutions in the connection domain and in the RNase H. Especially E399D seemed to be associated with an antiretroviral treatment and N-terminal resistance-delivering mutations.
  
  
  CONCLUSIONS
  some of the identified substitutions were associated with antiviral treatment and drug resistance-associated mutations. Due to the low prevalence of C-terminal mutations and as only a few of them could be associated with antiviral treatment and N-terminal resistance-delivering mutations, we would not recommend routinely testing of the C-terminal RT region.
authors.affiliation: J.W. Goethe University Hospital, Institute for Med. Virology, Paul Ehrlich Str. 40, 60596 Frankfurt, Germany.
authors.forename: I
authors.initials: I
authors.lastname: Michels
authors.forename: S
authors.initials: S
authors.lastname: Staszewski
authors.forename: L
authors.initials: L
authors.lastname: Gürtler
authors.forename: G
authors.initials: G
authors.lastname: Nisius
authors.forename: A
authors.initials: A
authors.lastname: Müller
authors.forename: L
authors.initials: L
authors.lastname: Locher
authors.forename: H-W
authors.initials: HW
authors.lastname: Doerr
authors.forename: Martin
authors.initials: M
authors.lastname: Stürmer
mesh_terms: D019943:Amino Acid Substitution; D019380:Anti-HIV Agents / Q000627:therapeutic use*; D044966:Anti-Retroviral Agents / Q000627:therapeutic use; D004351:Drug Resistance; D015658:HIV Infections / Q000821:virology; D054303:HIV Reverse Transcriptase / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology / Q000235:genetics; D006801:Humans; D009154:Mutation; D016133:Polymerase Chain Reaction / Q000379:methods; D012367:RNA, Viral / Q000235:genetics; D019914:Taq Polymerase / Q000235:genetics; D014779:Virus Replication / Q000187:drug effects; D015215:Zidovudine / Q000627:therapeutic use
chemical_list: D019380:Anti-HIV Agents; D044966:Anti-Retroviral Agents; D012367:RNA, Viral; D015215:Zidovudine; D019914:Taq Polymerase; D054303:HIV Reverse Transcriptase