title: [Subtype and sequence analysis of the C2-V3 region of gp120 genes among HIV-1 strains in Sichuan province].
abstract: Nine DNA fragments of HIV-1 env gene were amplified by PCR from uncultured peripheral blood mononuclear cells (PBMCs) obtained from HIV-1 sero-positive intravenous drug users (IDUs) in Sichuan province, in mid 1996. Their C2-V3 region (about 450 bp) was sequenced. Sequence analysis showed that there were two HIV-1 subtypes B and C, with 1.4% and 2.6% gene divergence inside each subtype, in Sichuan. The 5 subtype B strains, when comparing with sequences of several reference HIV-1 strains, were found similar to these identified in Thailand, Myanma and Yunnan province. The nucleotide sequence divergence between them was ranged from 3.6% to 4.3%. Meanwhile, the 4 subtype C strains except sc3, were most close to those found in India as well as in Yunnan province, and both their nucleotide sequence divergence was 3.1%. The sc3 strain belonged to subtype C but had larger genetic distance, between 10.1%-17.2%. Above results suggested a recent epidemic of both subtype HIV-1 strains in Sichuan provine and they were very close to those identified in Yunnan province: The subtype C strain of sc3 is special and its source remains not clear.
mesh_terms: D002681:China; D004279:DNA, Viral / Q000235:genetics; D005814:Genes, Viral; D014644:Genetic Variation; D015699:HIV Envelope Protein gp120 / Q000235:genetics*; D006679:HIV Seropositivity / Q000821:virology; D015497:HIV-1 / Q000145:classification / Q000235:genetics*; D006801:Humans; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA