title: Selection and characterization of HIV-1 with a novel S68 deletion in reverse transcriptase.
abstract: Resistance to human immunodeficiency virus type 1 (HIV-1) represents a significant problem in the design of novel therapeutics and the management of treatment regimens in infected persons. Resistance profiles can be elucidated by defining modifications to the viral genome conferred upon exposure to novel nucleoside reverse transcriptase (RT) inhibitors (NRTI). In vitro testing of HIV-1LAI-infected primary human lymphocytes treated with β-D-2',3'-dideoxy-2',3'-didehydro-5-fluorocytidine (DFC; Dexelvucitabine; Reverset) produced a novel deletion of AGT at codon 68 (S68Δ) alone and in combination with K65R that differentially affects drug response. Dual-approach clone techniques utilizing TOPO cloning and pyrosequencing confirmed the novel S68Δ in the HIV-1 genome. The S68Δ HIV-1 RT was phenotyped against various antiviral agents in a heteropolymeric DNA polymerase assay and in human lymphocytes. Drug susceptibility results indicate that the S68Δ displayed a 10- to 30-fold increase in resistance to DFC, lamivudine, emtricitabine, tenofovir, abacavir, and amdoxovir and modest resistance to stavudine, β-d-2',3'-oxa-5-fluorocytidine, or 9-(β-D-1,3-dioxolan-4-yl)guanine and remained susceptible to 3'-azido-3'-deoxythymidine, 2',3'-dideoxyinosine (ddI), 1-(β-D-dioxolane)thymine (DOT) and lopinavir. Modeling revealed a central role for S68 in affecting conformation of the β3-β4 finger region and provides a rational for the selective resistance. These data indicate that the novel S68Δ is a previously unrecognized deletion that may represent an important factor in NRTI multidrug resistance treatment strategies.
authors.affiliation: Center for AIDS Research, Laboratory of Biochemical Pharmacology, Department of Pediatrics, Emory University School of Medicine, and Veterans Affairs Medical Center, 1670 Clairmont Rd., Medical Research 151H, Decatur, GA 30033, UsA. rschina@emory.edu
authors.forename: Raymond F
authors.initials: RF
authors.lastname: Schinazi
authors.forename: Ivana
authors.initials: I
authors.lastname: Massud
authors.forename: Kimberly L
authors.initials: KL
authors.lastname: Rapp
authors.forename: Meta
authors.initials: M
authors.lastname: Cristiano
authors.forename: Mervi A
authors.initials: MA
authors.lastname: Detorio
authors.forename: Richard A
authors.initials: RA
authors.lastname: Stanton
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Bennett
authors.forename: Monique
authors.initials: M
authors.lastname: Kierlin-Duncan
authors.forename: Johan
authors.initials: J
authors.lastname: Lennerstrand
authors.forename: James H
authors.initials: JH
authors.lastname: Nettles
mesh_terms: D002478:Cells, Cultured; D024882:Drug Resistance, Viral / Q000235:genetics; D054303:HIV Reverse Transcriptase / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D015497:HIV-1 / Q000187:drug effects* / Q000201:enzymology* / Q000235:genetics; D006801:Humans; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D017433:Protein Structure, Secondary; D018894:Reverse Transcriptase Inhibitors / Q000494:pharmacology*
chemical_list: D018894:Reverse Transcriptase Inhibitors; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase