Study On Variation Of HIV-1 Gag, Env, Pol Genes From Partial HIV-infected Individuals In Henan Province

The main objective of this research is to study the relationship of gene variation, host selective pressures,antigen epitope shifts,glycosylation site mutation and primary drug resistance in HIV-1 subtype B' strains collected in Henan province.The result of the paper will contribute to the immunology of HIV-1,the ongoing development of the HIV vaccine and the AIDS clinical treatment.The partial region of HIV-1 gag,env,and pol gene was amplified by nested polymerase chain reaction(PCR),purified PCR products were cloned and sequenced.The PCR and cloned sequences of gag,env and pol genes from 54,45 and 48 HIV-infected individuals, were analyzed by Mega3.0,Bioedit,Clustal X and SPSS 13.0 soft wares.Phylogenetic trees showed that the gag genes were clustered with Thailand B.TH92.92TH014 strains and China Yunan province B.CN.RL42 strains.The genetic distances of the gag and env genes were 2.65 0.95,4.05 0.93,which were significantly closed to Thailand B.TH92.92TH014 strains.The genetic distance of the PCR sequences compared to the cloned strain's sequences showed no statistical difference.In the study of antigen epitopes we found that there were 4 mutations in the amino consensus of our studied gag genes compared to 9 antigen epitopes which were restricted by main HLA.The mutations in antigen epitopes focused on the p17 region of the gag gene,and located on E62G,Y79F,193V and T84V,respectively.This trend was consistent with the changes of genetic distances and selective pressures. The data showed that p17 region seemed to get more immune pressures,and displayed more genetic diversity and variation epitopes than the p24 region.Remarkable variation was observed in flanking region between GAG p17 and p24.The analyses of sequences revealed that many nucleotides substitution, insertion,deletion,repeat and inversion of gene segments generally occurred in the region.The remarkable mutation rarely caused the reading frame shift and no change for enzyme sites.It seemed that the region lacked the significant function was permited the greater variation.The V3 loop tip motifs had four types in our study(GPGR,GPGQ,GPGK,GQGR),and the GPGR which was the typical Western V3 loop tip motifs was 44%.Besides the 10-12 and 35-37 glycosylated sites of env gene,all mutations were found in the other glycosylated sites.This paper predicted the possible HIV co-receptor of the HIV-infected individuals on the key amino acides and on number of the electrostatic charge of the V3 loop.Five sequences seemed to match the CXCR4,and six sequences seemed to match CCR5,The others could not be determined.The study on the drug resistance in primary treatment patients showed that there were not major resistance associated with PI,and the resistance were minor mutations in protease gene.In the RT region,there were 9 resistance mutants 3 of 9 from PCR sequences and other from cloned sequences.All the resistance mutants were single NRTIs or NNRTIs,The results showed that the percentage of primary drug resistance was still low in our study region,suggesting no need for genotyping detection in blood donor patients before primary therapy.