The human immunodeficiency virus type 1 (HIV-1) vif gene encodes a 23-
kDa protein (viral infectivity factor) whose exact mechanism of action
is not entirely clear. Vif is believed to be highly conserved among d
ifferent HIV-1 strains. We have analyzed the proviral vif sequences of
61 peripheral blood mononuclear cell samples from HIV-1 positive pati
ents by direct solid phase sequencing and temperature gradient gel ele
ctrophoresis of polymerase chain reaction products. Inter- and intrain
dividual sequence variations, conserved motifs, and prevalent vif subt
ypes were investigated, The consensus proviral vif DNA sequence of the
61 samples as well as the consensus sequence of the 61 deduced vif am
ino acid sequences were found to be less conserved than previously tho
ught. The vif proviral sequences were 58% conserved, with the 5' end o
f the vif gene being the most conserved region (84%). Of the vif amino
acids only 45% were absolutely conserved in the 61 samples, i.e., the
absolutely conserved and as such possibly functionally important doma
ins of the vif protein comprised less than half of the vif amino acids
. In two-thirds of the variable positions residues belonging to differ
ent amino acid groups were found. In individual patients the prevalent
vif sequence changed with the course of disease, but the differences
found in two serial samples of a patient were less than or equal to 10
%. Phylogenetic analysis revealed that one African vif subtype had bee
n introduced in the investigated population. (C) 1994 Academic Press,
Inc.