Role of the long cytoplasmic domain of the SIV Env glycoprotein in early and late stages of infection

<p>Abstract</p> <p>Background</p> <p>The Env glycoproteins of retroviruses play an important role in the initial steps of infection involving the binding to cell surface receptors and entry by membrane fusion. The Env glycoprotein also plays an important role in viral assembly at a late step of infection. Although the Env glycoprotein interacts with viral matrix proteins and cellular proteins associated with lipid rafts, its possible role during the early replication events remains unclear. Truncation of the cytoplasmic tail (CT) of the Env glycoprotein is acquired by SIV in the course of adaptation to human cells, and is known to be a determinant of SIV pathogenicity.</p> <p>Results</p> <p>We compared SIV viruses with full length or truncated (T) Env glycoproteins to analyze possible differences in entry and post-entry events, and assembly of virions. We observed that early steps in replication of SIV with full length or T Env were similar in dividing and non-dividing cells. However, the proviral DNA of the pathogenic virus clone SIVmac239 with full length Env was imported to the nucleus about 20-fold more efficiently than proviral DNA of SIVmac239T with T Env, and 100-fold more efficiently than an SIVmac18T variant with a single mutation A239T in the SU subunit and with a truncated cytoplasmic tail (CT). In contrast, proviral DNA of SIVmac18 with a full length CT and with a single mutation A239T in the SU subunit was imported to the nucleus about 50-fold more efficiently than SIVmac18T. SIV particles with full length Env were released from rhesus monkey PBMC, whereas a restriction of release of virus particles was observed from human 293T, CEMx174, HUT78 or macrophages. In contrast, SIV with T Envs were able to overcome the inhibition of release in human HUT78, CEMx174, 293T or growth-arrested CEMx174 cells and macrophages resulting in production of infectious particles. We found that the long CT of the Env glycoprotein was required for association of Env with lipid rafts. An Env mutant C787S which eliminated palmitoylation did not abolish Env incorporation into lipid rafts, but prevented virus assembly.</p> <p>Conclusion</p> <p>The results indicate that the long cytoplasmic tail of the SIV Env glycoprotein may govern post-entry replication events and plays a role in the assembly process.</p

Three-dimensional Huh7 cell culture system for the study of Hepatitis C virus infection

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A Search for Centrally Produced non-qqˉ q \bar{q} Mesons in Proton Proton Interactions at 450~GeV/c using the CERN Ω\Omega Spectrometer and GAMS-4000

% WA102 \\ \\ During the last decade evidence for non-$q \bar{q}$ mesons has grown due to experiments having high statistics in various decay modes. However there are still many channels which have promising signals but any definite conclusion is limited by the available statistics. In order to make a significant contribution to this field we propose to perform two 100~day runs combining the efficient multiphoton detection of GAMS-4000 with the good charged particle detection of the Omega Spectrometer to search for other non-$q \bar{q}$ mesons in the reaction $pp \rightarrow p _{f} X ^{o} p _{s}$ at 450~GeV/c. Although many final states will be studied those decaying to $\eta \eta, \eta \eta ^\prime$ and $\eta ^\prime \eta ^\prime$ are of particular interest and the statistics in these channels will be greatly enhanced. This study will act as an important input in helping to understand non-perturbative QCD