Molecular characterization of human immunodeficiency virus from Zaire: nucleotide sequence analysis identifies...

To examine the genetic relatedness of human immunodeficiency viruses (HIV) from different geographic locations, we molecularly cloned the genome of HIV isolated from a Zairian AIDS patient. Restriction mapping of the recombinant clone, designated HIV-Zr6, revealed both common (as observed in other HIV isolates) and unique restriction sites. The DNA clone of HIV-Zr6, shown to give rise to infectious cytopathic virus after transfection of cultured lymphoid cells, was sequenced in several regions. The long terminal repeat (LTR), open reading frame 1 (ORF1), C-terminal envelope (env) gene domain, and ORF2 showed less than 6% difference in nucleotide sequence when compared to other HIV isolates including human T-lymphotropic virus-type III (HTLV-III) clone B10, lymphadenopathy-associated virus-1 (LAV-1), and AIDS-associated retrovirus-2 (ARV-2). About 15% difference in nucleotide sequences was noted in the N-terminal env gene domain. Alignments of env gene sequences revealed conserved, moderately variable, and hypervariable stretches in the predicted amino acid sequences. This model provides a basis for assessing the significance of sequence variation on properties controlled by the viral Env glycoproteins such as cell tropism and immunogenicity.