title: Amino acid substitutions in Gag protein at non-cleavage sites are indispensable for the development of a high multitude of HIV-1 resistance against protease inhibitors.
abstract: Amino acid substitutions in human immunodeficiency virus type 1 (HIV-1) Gag cleavage sites have been identified in HIV-1 isolated from patients with AIDS failing chemotherapy containing protease inhibitors (PIs). However, a number of highly PI-resistant HIV-1 variants lack cleavage site amino acid substitutions. In this study we identified multiple novel amino acid substitutions including L75R, H219Q, V390D/V390A, R409K, and E468K in the Gag protein at non-cleavage sites in common among HIV-1 variants selected against the following four PIs: amprenavir, JE-2147, KNI-272, and UIC-94003. Analyses of replication profiles of various mutant clones including competitive HIV-1 replication assays demonstrated that these mutations were indispensable for HIV-1 replication in the presence of PIs. When some of these mutations were reverted to wild type amino acids, such HIV-1 clones failed to replicate. However, virtually the same Gag cleavage pattern was seen, indicating that the mutations affected Gag protein functions but not their cleavage sensitivity to protease. These data strongly suggest that non-cleavage site amino acid substitutions in the Gag protein recover the reduced replicative fitness of HIV-1 caused by mutations in the viral protease and may open a new avenue for designing PIs that resist the emergence of PI-resistant HIV-1.
authors.affiliation: Experimental Retrovirology Section, HIV and AIDS Malignancy Branch, NCI, National Institutes of Health, Bethesda, Maryland 20892, USA.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Gatanaga
authors.forename: Yasuhiro
authors.initials: Y
authors.lastname: Suzuki
authors.forename: Hsinyi
authors.initials: H
authors.lastname: Tsang
authors.forename: Kazuhisa
authors.initials: K
authors.lastname: Yoshimura
authors.forename: Mark F
authors.initials: MF
authors.lastname: Kavlick
authors.forename: Kunio
authors.initials: K
authors.lastname: Nagashima
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gorelick
authors.forename: Sek
authors.initials: S
authors.lastname: Mardy
authors.forename: Chun
authors.initials: C
authors.lastname: Tang
authors.forename: Michael F
authors.initials: MF
authors.lastname: Summers
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mitsuya
mesh_terms: D000595:Amino Acid Sequence; D019943:Amino Acid Substitution; D019380:Anti-HIV Agents / Q000494:pharmacology; D002219:Carbamates; D002460:Cell Line; D003001:Cloning, Molecular; D004352:Drug Resistance, Microbial; D005663:Furans; D015683:Gene Products, gag / Q000737:chemistry / Q000378:metabolism*; D017320:HIV Protease Inhibitors / Q000494:pharmacology*; D015497:HIV-1 / Q000187:drug effects / Q000235:genetics* / Q000254:growth & development; D006801:Humans; D008969:Molecular Sequence Data; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D015183:Restriction Mapping; D013449:Sulfonamides / Q000494:pharmacology
chemical_list: D019380:Anti-HIV Agents; D002219:Carbamates; D005663:Furans; D015683:Gene Products, gag; D017320:HIV Protease Inhibitors; D011994:Recombinant Proteins; D013449:Sulfonamides; C095108:amprenavir