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: Lack of adaptation to human tetherin in HIV-1 Group O and P. | Yang et al. Retrovirology 2011 8 78 http content 8 1 78 RETR0VIR0L0GY RESEARCH Open Access Lack of adaptation to human tetherin in HIV-1 Group O and P Su Jung Yang Lisa A Lopez Colin M Exline Kevin G Haworth and Paula M Cannon Abstract Background HIV-1 viruses are categorized into four distinct groups M N O and P. Despite the same genomic organization only the group M viruses are responsible for the world-wide pandemic of AIDS suggesting better adaptation to human hosts. Previously it has been reported that the group M Vpu protein is capable of both down-modulating CD4 and counteracting BST-2 tetherin restriction while the group O Vpu cannot antagonize tetherin. This led us to investigate if group O and the related group P viruses possess functional anti-tetherin activities in Vpu or another viral protein and to further map the residues required for group M Vpu to counteract human tetherin. Results We found a lack of activity against human tetherin for both the Vpu and Nef proteins from group O and P viruses. Furthermore we found no evidence of anti-human tetherin activity in a fully infectious group O proviral clone ruling out the possibility of an alternative anti-tetherin factor in this virus. Interestingly an activity against primate tetherins was retained in the Nef proteins from both a group O and a group P virus. By making chimeras between a functional group M and non-functional group O Vpu protein we were able to map the first 18 amino acids of group M Vpu as playing an essential role in the ability of the protein to antagonize human tetherin. We further demonstrated the importance of residue alanine-18 for the group M Vpu activity. This residue lies on a diagonal face of conserved alanines in the TM domain of the protein and is necessary for specific Vpu-tetherin interactions. Conclusions The absence of human specific anti-tetherin activities in HIV-1 group O and P suggests a failure of these viruses to adapt to human hosts which may
