title: Mutations that abrogate human immunodeficiency virus type 1 reverse transcriptase dimerization affect maturation of the reverse transcriptase heterodimer.
abstract: The specific impact of mutations that abrogate human immunodeficiency virus type 1 (HIV-1) reverse transcriptase (RT) dimerization on virus replication is not known, as mutations shown previously to inhibit RT dimerization also impact Gag-Pol stability, resulting in pleiotropic effects on HIV-1 replication. We have previously characterized mutations at codon 401 in the HIV-1 RT tryptophan repeat motif that abrogate RT dimerization in vitro, leading to a loss in polymerase activity. The introduction of the RT dimerization-inhibiting mutations W401L and W401A into HIV-1 resulted in the formation of noninfectious viruses with reduced levels of both virion-associated and intracellular RT activity compared to the wild-type virus and the W401F mutant, which does not inhibit RT dimerization in vitro. Steady-state levels of the p66 and p51 RT subunits in viral lysates of the W401L and W401A mutants were reduced, but no significant decrease in Gag-Pol was observed compared to the wild type. In contrast, there was a decrease in processing of p66 to p51 in cell lysates for the dimerization-defective mutants compared to the wild type. The treatment of transfected cells with indinavir suggested that the HIV-1 protease contributed to the degradation of virion-associated RT subunits. These data demonstrate that mutations near the RT dimer interface that abrogate RT dimerization in vitro result in the production of replication-impaired viruses without detectable effects on Gag-Pol stability or virion incorporation. The inhibition of RT activity is most likely due to a defect in RT maturation, suggesting that RT dimerization represents a valid drug target for chemotherapeutic intervention.
authors.affiliation: Molecular Interactions Group, Macfarlane Burnet Institute for Medical Research and Public Health, 85 Commercial Road, GPO Box 2284, Melbourne, Victoria 3001, Australia.
authors.forename: Johanna
authors.initials: J
authors.lastname: Wapling
authors.forename: Katie L
authors.initials: KL
authors.lastname: Moore
authors.forename: Secondo
authors.initials: S
authors.lastname: Sonza
authors.forename: Johnson
authors.initials: J
authors.lastname: Mak
authors.forename: Gilda
authors.initials: G
authors.lastname: Tachedjian
mesh_terms: D003062:Codon; D019281:Dimerization; D015683:Gene Products, gag / Q000378:metabolism; D016655:HIV Core Protein p24 / Q000378:metabolism; D016333:HIV Protease / Q000378:metabolism; D054303:HIV Reverse Transcriptase / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D019469:Indinavir / Q000494:pharmacology; D009154:Mutation; D011498:Protein Precursors / Q000378:metabolism; D014771:Virion / Q000201:enzymology / Q000502:physiology
chemical_list: D003062:Codon; D015683:Gene Products, gag; D016655:HIV Core Protein p24; D011498:Protein Precursors; C059767:p55 gag precursor protein, Human immunodeficiency virus 1; D019469:Indinavir; D054303:HIV Reverse Transcriptase; D016333:HIV Protease