title: Mutations conferring resistance to human immunodeficiency virus type 1 fusion inhibitors are restricted by gp41 and Rev-responsive element functions.
abstract: One of the human immunodeficiency virus (HIV) envelope proteins, gp41, plays a key role in HIV fusion. A gp41-derived peptide, T-20, efficiently inhibits HIV fusion and is currently approved for treatment of HIV-infected individuals. Although resistant variants have been reported, the mechanism of the resistance remains to be defined. To elucidate the mechanism in detail, we generated variants resistant to C34, a peptide derived from the gp41 carboxyl terminus heptad repeat (C-HR) in vitro. The resistant variants had a 5-amino-acid deletion in gp120 and a total of seven amino acid substitutions in gp41. Binding assays revealed that an I37K substitution in the N-terminal heptad repeat (N-HR) impaired the binding of C34, whereas an N126K substitution in the C-HR enhanced the binding to mutated N-HR, indicating that both mutations were directly involved in resistance. On the other hand, substitutions for A30 and D36 seemed to be secondary mutations, located complementary to each other in the Rev-responsive element (RRE), and were mutated simultaneously to maintain the secondary structure of the RRE that was impaired by the mutations at I37. Thus, HIV acquired resistance to C34 by mutations in N-HR, which directly interacted with C34. However, since this region also encoded the RRE, additional mutations were required to maintain viral replication. These results suggest that HIV fusion is one of the attractive targets for HIV chemotherapy.
authors.affiliation: Laboratory of Virus Immunology, Institute for Virus Research, Kyoto University, 53 Shogoin Kawaramachi, Sakyoku, Kyoto 606-8507, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Nameki
authors.forename: Eiichi
authors.initials: E
authors.lastname: Kodama
authors.forename: Mieko
authors.initials: M
authors.lastname: Ikeuchi
authors.forename: Naoto
authors.initials: N
authors.lastname: Mabuchi
authors.forename: Akira
authors.initials: A
authors.lastname: Otaka
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Tamamura
authors.forename: Mutsuhito
authors.initials: M
authors.lastname: Ohno
authors.forename: Nobutaka
authors.initials: N
authors.lastname: Fujii
authors.forename: Masao
authors.initials: M
authors.lastname: Matsuoka
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D019556:COS Cells; D024882:Drug Resistance, Viral; D015752:Genes, env / Q000502:physiology*; D015700:HIV Envelope Protein gp41 / Q000494:pharmacology* / Q000502:physiology*; D023581:HIV Fusion Inhibitors / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects*; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D010446:Peptide Fragments / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014779:Virus Replication / Q000187:drug effects
chemical_list: D015700:HIV Envelope Protein gp41; D023581:HIV Fusion Inhibitors; D010446:Peptide Fragments; C407149:peptide C34