title: Mutations at human immunodeficiency virus type 1 reverse transcriptase tryptophan repeat motif attenuate the inhibitory effect of efavirenz on virus production.
abstract: HIV-1 virus particle processing is mediated by protease (PR), with enzymatic activation triggered by Gag-Pol/Gag-Pol interaction. We previously reported that truncation mutations at the reverse transcriptase (RT) connection subdomain markedly impair virus particle processing, suggesting an important role for the RT subdomain in PR-mediated virus processing. A highly conserved tryptophan (Trp) repeat motif of the HIV-1 RT connection subdomain is involved in RT dimerization. Our goal in this study was to determine whether mutations at the Trp repeat motif have any effect on PR-mediated virus processing. Our results indicate that even though alanine substitutions at W401 (W401A) or at both W401 and W402 (W401A/W402A) have no major effect on steady-state virus processing, the combined W401A/W402A mutations partially negate and the W401A mutation almost completely negates an efavirenz (EFV)-imposed barrier to virus production. The combination of RT instability and poor enzymatic activity reflects a RT dimerization defect incurred by the mutations. We also found that an artificial p66RT carrying the W401A or W401A/W402A mutations was packaged into virions more efficiently than wild-type p66RT, and that the viral incorporation of p66RT is significantly reduced by EFV, implying a novel effect of EFV on RT-Gag interaction. Our results suggest that the Trp repeat motif may play a role in the Gag-Pol/Gag-Pol interaction that contributes to subsequent PR activation.
authors.affiliation: Department of Medical Research and Education, Taipei Veterans General Hospital, Taiwan.
authors.forename: Chien-Cheng
authors.initials: CC
authors.lastname: Chiang
authors.forename: Shiu-Mei
authors.initials: SM
authors.lastname: Wang
authors.forename: Ying-Tzu
authors.initials: YT
authors.lastname: Tseng
authors.forename: Kuo-Jung
authors.initials: KJ
authors.lastname: Huang
authors.forename: Chin-Tien
authors.initials: CT
authors.lastname: Wang
mesh_terms: D000480:Alkynes; D020816:Amino Acid Motifs; D019943:Amino Acid Substitution / Q000235:genetics; D019380:Anti-HIV Agents / Q000494:pharmacology*; D048588:Benzoxazines / Q000494:pharmacology*; D002460:Cell Line; D003521:Cyclopropanes; D054303:HIV Reverse Transcriptase / Q000235:genetics*; D015497:HIV-1 / Q000187:drug effects* / Q000235:genetics; D006801:Humans; D020125:Mutation, Missense; D019065:Virus Assembly / Q000187:drug effects / Q000235:genetics
chemical_list: D000480:Alkynes; D019380:Anti-HIV Agents; D048588:Benzoxazines; D003521:Cyclopropanes; C514824:reverse transcriptase, Human immunodeficiency virus 1; D054303:HIV Reverse Transcriptase; C098320:efavirenz