Determinants for the syncytium-inducing phenotype of HIV-1 subtype F isolates are located in the V3 region.
The HIV-1 syncytium-inducing phenotype is determined by virus replication and the presence of cytopathic effects in MT-2 cells. There is a strong correlation between the syncytium-inducing/MT-2-tropic phenotype and positively charged amino acids at positions 306 and 320 in the V3 loop for HIV-1 subtypes A, B, D, and E. In contrast, a lack of correlation between signature amino acids and syncytium formation in MT-2 cells for subtype F viruses from Romania has been reported. Virus phenotype and V3 loop amino acid sequences from Romanian HIV-1 subtype F isolates were further investigated in the present study. While the determinants of MT-2 tropism are clearly harbored in the V3 loop of subtype F isolates from Romania, the induction of syncytium formation occurs in the presence or absence of positively charged amino acids at positions 306, 320, and/or 324. However, the net positive charge of V3 loop sequences derived from syncytium-inducing viruses was higher than that of the nonsyncytium-inducing isolate.
Holm-Hansen
C
C
Center for International Health, University of Bergen, Norway.
Baan
E
E
Asjö
B
B
Pascu
F R
FR
Goudsmit
J
J
De Jong
J J
JJ
D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D002460:Cell Line; D003588:Cytopathogenic Effect, Viral / Q000235:genetics; D004563:Electrochemistry; D015699:HIV Envelope Protein gp120 / Q000737:chemistry / Q000235:genetics*; D015497:HIV-1 / Q000145:classification* / Q000235:genetics / Q000472:pathogenicity*; D006801:Humans; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000235:genetics*; D010641:Phenotype; D017386:Sequence Homology, Amino Acid
D000596:Amino Acids; D015699:HIV Envelope Protein gp120; C059762:HIV envelope protein gp120 (305-321); D010446:Peptide Fragments