title: "Cytoplasmic domain effects on exposure of co-receptor-binding sites of HIV-1 Env".
abstract: We defined the effects of the cytoplasmic domain (CT) of the Env glycoprotein on co-receptor usage of HIV-1 by reciprocal exchanges of regions containing V3-V5 loops between CD4-dependent and CD4-independent isolates. Primary HIV-1 isolate Env clones CD8 CXCR4-tropic 92UG046 CT84 with an 84-aa truncated CT domain, CD4 CXCR4-tropic 92UG046, and CD4 CCR5-tropic SF162 with full-length (FL) CT domains were used for comparison. The parental 92UG046 Env with CT84 was not fusogenic, but a chimeric SF162 V3-V5-CT84 with an 84-aa truncated CT domain, which demonstrated a switched co-receptor specificity, exhibited syncytium-formation activity with 3T3T4X4 cells. The wild-type (WT) SF162 Env with CT84 or full-length CT was fusogenic in 3T3T4R5 cells. By exchange of V3-V5 loops, we were able to alter WT SF162 to switch its co-receptor preference, which was not dependent on CT domain length. These results provide evidence that CT domains can induce conformational changes in functional regions of gp120 and determine receptor tropism but do not modulate HIV-1 co-receptor specificity.
authors.affiliation: Department of Microbiology and Immunology and Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, 30322, USA. avzorov@emory.edu.|Ivanovsky Institute of Virology, Gamaleya Federal Research Center of Epidemiology and Microbiology, Moscow, 123098, Russian Federation. avzorov@emory.edu.
authors.forename: Andrei N
authors.initials: AN
authors.lastname: Vzorov
authors.affiliation: Department of Microbiology and Immunology and Emory Vaccine Center, Emory University School of Medicine, Atlanta, GA, 30322, USA.
authors.forename: Richard W
authors.initials: RW
authors.lastname: Compans
mesh_terms: D001665:Binding Sites; D002460:Cell Line; D015699:HIV Envelope Protein gp120 / Q000235:genetics / Q000378:metabolism*; D015497:HIV-1 / Q000235:genetics / Q000502:physiology*; D006801:Humans; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D011487:Protein Conformation; D000072417:Protein Domains; D015728:Receptors, HIV / Q000378:metabolism*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D056189:Viral Tropism; D053585:Virus Attachment
chemical_list: D015699:HIV Envelope Protein gp120; D050505:Mutant Proteins; D015728:Receptors, HIV; D011994:Recombinant Proteins