title: Identification of two distinct human immunodeficiency virus type 1 Vif determinants critical for interactions with human APOBEC3G and APOBEC3F.
abstract: Human cytidine deaminases APOBEC3G (A3G) and APOBEC3F (A3F) inhibit replication of Vif-deficient human immunodeficiency virus type 1 (HIV-1). HIV-1 Vif overcomes these host restriction factors by binding to them and inducing their proteasomal degradation. The Vif-A3G and Vif-A3F interactions are attractive targets for antiviral drug development because inhibiting the interactions could allow the host defense mechanism to control HIV-1 replication. It was recently reported that the Vif amino acids D(14)RMR(17) are important for functional interaction and degradation of the previously identified Vif-resistant mutant of A3G (D128K-A3G). However, the Vif determinants important for functional interaction with A3G and A3F have not been fully characterized. To identify these determinants, we performed an extensive mutational analysis of HIV-1 Vif. Our analysis revealed two distinct Vif determinants, amino acids Y(40)RHHY(44) and D(14)RMR(17), which are essential for binding to A3G and A3F, respectively. Interestingly, mutation of the A3G-binding region increased Vif's ability to suppress A3F. Vif binding to D128K-A3G was also dependent on the Y(40)RHHY(44) region but not the D(14)RMR(17) region. Consistent with previous observations, subsequent neutralization of the D128K-A3G antiviral activity required substitution of Vif determinant D(14)RMR(17) with SEMQ, similar to the SERQ amino acids in simian immunodeficiency virus SIV(AGM) Vif, which is capable of neutralizing D128K-A3G. These studies are the first to clearly identify two distinct regions of Vif that are critical for independent interactions with A3G and A3F. Pharmacological interference with the Vif-A3G or Vif-A3F interactions could result in potent inhibition of HIV-1 replication by the APOBEC3 proteins.
authors.affiliation: HIV Drug Resistance Program, National Cancer Institute-Frederick, P.O. Box B, Bldg. 535, Rm. 334, Frederick, MD 21702-1201, USA.
authors.forename: Rebecca A
authors.initials: RA
authors.lastname: Russell
authors.forename: Vinay K
authors.initials: VK
authors.lastname: Pathak
mesh_terms: D000071480:APOBEC-3G Deaminase; D000409:Alanine / Q000378:metabolism; D002460:Cell Line; D003564:Cytidine Deaminase; D043525:Cytosine Deaminase / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D004252:DNA Mutational Analysis; D016346:Gene Products, vif / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000378:metabolism*; D006801:Humans; D016296:Mutagenesis; D009700:Nucleoside Deaminases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D011485:Protein Binding; D012097:Repressor Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D054320:vif Gene Products, Human Immunodeficiency Virus
chemical_list: D016346:Gene Products, vif; D012097:Repressor Proteins; D054320:vif Gene Products, Human Immunodeficiency Virus; D009700:Nucleoside Deaminases; C492906:APOBEC3F protein, human; D043525:Cytosine Deaminase; D000071480:APOBEC-3G Deaminase; C464924:APOBEC3G protein, human; D003564:Cytidine Deaminase; D000409:Alanine