tailieunhanh - Báo cáo y học: "Enrichment of intersubtype HIV-1 recombinants in a dual infection system using HIV-1 strain-specific siRNAs"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Respiratory Research cung cấp cho các bạn kiến thức về ngành y đề tài: Enrichment of intersubtype HIV-1 recombinants in a dual infection system using HIV-1 strain-specific siRNAs. | Gao et al. Retrovirology 2011 8 5 http content 8 1 5 RETROVIROLOGY RESEARCH Open Access Enrichment of intersubtype HIV-1 recombinants in a dual infection system using HIV-1 strain-specific siRNAs z 1 1 1 1 2 1 Yong Gao Measho Abreha Kenneth N Nelson Heather Baird Dawn M Dudley Awet Abraha Eric J Arts Abstract Background Intersubtype HIV-1 recombinants in the form of unique or stable circulating recombinants forms CRFs are responsible for over 20 of infections in the worldwide epidemic. Mechanisms controlling the generation selection and transmission of these intersubtype HIV-1 recombinants still require further investigation. All intersubtype HIV-1 recombinants are generated and evolve from initial dual infections but are difficult to identify in the human population. In vitro studies provide the most practical system to study mechanisms but the recombination rates are usually very low in dual infections with primary HIV-1 isolates. This study describes the use of HIV-1 isolate-specific siRNAs to enrich intersubtype HIV-1 recombinants and inhibit the parental HIV-1 isolates from a dual infection. Results Following a dual infection with subtype A and D primary HIV-1 isolates and two rounds of siRNA treatment nearly 100 of replicative virus was resistant to a siRNA specific for an upstream target sequence in the subtype A envelope env gene as well as a siRNA specific for a downstream target sequence in the subtype D env gene. Only 20 10 50 of the replicating virus had nucleotide substitutions in the siRNA-target sequence whereas the remaining 78 39 50 harbored a recombination breakpoint that removed both siRNA target sequences and rendered the intersubtype D A recombinant virus resistant to the dual siRNA treatment. Since siRNAs target the newly transcribed HIV-1 mRNA the siRNAs only enrich intersubtype env recombinants and do not influence the recombination process during reverse transcription. Using this system a strong bias is selected .