Objective: To characterize full length glycoprotein 120 gene variations of 21 HIV-1 CRF01_AE isolated in Fujian, China, so as to help in the immunogenic research and vaccine design.
Methods: Twenty-one peripheral blood samples were randomly collected form 100 HIV-1CRF01_AE infected persons in Fujian 2004 approximately 2005. DNA was extracted, Nested-PCR was used to amplify the envelop protein full length gp120 gene. The PVR products underwent Sepharose electrophoresis. Genotype identification was done by BLAST program. Sequence analysis was conducted with Megalign and CLUSTAL1.83. Phylogenetic tree and genetic distance were analyzed by Neighbor-joining method and Distance program of MEGA software. The amino acid similarity analysis was done with DNASIS, and N-glycosylation site analysis was done with N-GLYCOSIDE program.
Results: Phylogenetic tree analysis showed that these 21 HIV-1 subtype CRF01_AE strains clustered with the AE reference strain, with an overall genetic distance of 9.5% +/- 2.5%. There were four types of V3 loop central motif: GPGQ (71.43%), GPGR (19.05%), GPGH (4.76%), and GQGQ (4.76%). Prediction of the potential use of co-receptors on the basis of the critical amino acids within V3 loop disclosed potential use of CCR4/CCR5 in 16 of the 21 sequences (76.19%), potential use of CCR4/CCR5 in 1 sequence (4.76%), and 4 samples (19.05%) failed to be predicted. Amino acid sequence analysis showed that V3 region was relatively conservative, whereas V1, V2, V4, and V5 wee more variable. N-linked glycosylation site analysis showed that most of the 21 sequences were relatively conservative.
Conclusion: Sequences analysis show Most of the CRF01_AE virus strains in Fujian have a complicated source, and most of them are closely related to those of Southeast Asia and belong to the non-syncytium inducing (NSI) type.