tailieunhanh - Báo cáo y học: " Blocking premature reverse transcription fails to rescue the HIV-1 nucleocapsid-mutant replication defect"

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: Blocking premature reverse transcription fails to rescue the HIV-1 nucleocapsid-mutant replication defect. | Thomas et al. Retrovirology 2011 8 46 http content 8 1 46 RETROVIROLOGY RESEARCH Open Access Blocking premature reverse transcription fails to rescue the HIV-1 nucleocapsid-mutant replication defect James A Thomas Teresa L Shatzer and Robert J Gorelick Abstract Background The nucleocapsid NC protein of HIV-1 is critical for viral replication. Mutational analyses have demonstrated its involvement in viral assembly genome packaging budding maturation reverse transcription and integration. We previously reported that two conservative NC mutations His23Cys and His44Cys cause premature reverse transcription such that mutant virions contain approximately 1 000-fold more DNA than wild-type virus and are replication defective. In addition both mutants show a specific defect in integration after infection. Results In the present study we investigated whether blocking premature reverse transcription would relieve the infectivity defects which we successfully performed by transfecting proviral plasmids into cells cultured in the presence of high levels of reverse transcriptase inhibitors. After subsequent removal of the inhibitors the resulting viruses showed no significant difference in single-round infective titer compared to viruses where premature reverse transcription did occur there was no rescue of the infectivity defects in the NC mutants upon reverse transcriptase inhibitor treatment. Surprisingly time-course endogenous reverse transcription assays demonstrated that the kinetics for both the NC mutants were essentially identical to wild-type when premature reverse transcription was blocked. In contrast after infection of CD4 HeLa cells it was observed that while the prevention of premature reverse transcription in the NC mutants resulted in lower quantities of initial reverse transcripts the kinetics of reverse transcription were not restored to that of untreated wild-type HIV-1. Conclusions Premature reverse transcription is not the cause of .