tailieunhanh - Báo cáo y học: " Coupling of receptor interference and a hostdependent post-binding entry deficiency in a gammaretroviral envelope protein"

Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học Retrovirology cung cấp cho các bạn kiến thức về ngành y đề tài: Coupling of receptor interference and a hostdependent post-binding entry deficiency in a gammaretroviral envelope protein. | Bahrami et al. Retrovirology 2010 7 9 http content 7 1 9 RETR0VIR0L0GY RESEARCH Open Access Coupling of receptor interference and a hostdependent post-binding entry deficiency in a gammaretroviral envelope protein Shervin Bahrami1 2 Ditte Ejegod1 Karina Dalsgaard Sprensen1 Finn Skou Pedersen1 2 Abstract Background SL3-2 is a unique polytropic murine gammaretroviral isolate that is only able to infect murine cells. We have previously shown that two mutations R212G and T213I located on the surface of the receptor binding domain in a region designated the VR3 loop can alter the species tropism of this envelope protein. This location suggests that the VR3 loop composition has an influence on receptor interaction and thereby affects binding as well as superinfection resistance. In order to investigate this further we have studied the binding and interference patterns of the SL3-2 envelope and its mutants. Results We find unexpectedly that wild type SL3-2 envelope binds equally well to both permissive and non-permissive cells indicating a post binding defect when interacting with the human Xpr1. Using replication competent viruses containing envelopes from SL3-2 or its mutants we find that the same amino acid mutations can dramatically alter the interference profile of this polytropic ENV suggesting that the same amino acid changes that cause the post binding defect also influence interaction with the receptor. Conclusions The envelope protein of SL3-2 MLV shows an entry defect on non-murine cells. This is coupled to a dramatically reduced ability to interfere with entry of other polytropic viruses. Two point mutations in the VR3 loop of the receptor binding domain of this envelope result both in a much increased interference ability and in removing the post-binding defect on non-murine cells suggesting that both of these phenotypes are a consequence of insufficient interaction between the envelope and the receptor Background Retroviruses enter .