Identification of a methylated oligoribonucleotide as a potent inhibitor of HIV-1 reverse transcription complex

Upon HIV-1 infection of a target cell, the viral reverse transcriptase (RT) copies the genomic RNA to synthesize the viral DNA. The genomic RNA is within the incoming HIV-1 core where it is coated by molecules of nucleocapsid (NC) protein that chaperones the reverse transcription process. Indeed, the RT chaperoning properties of NC extend from the initiation of cDNA synthesis to completion of the viral DNA. New and effective drugs against HIV-1 continue to be required, which prompted us to search for compounds aimed at inhibiting NC protein. Here, we report that the NC chaperoning activity is extensively inhibited in vitro by small methylated oligoribonucleotides (mODN). These mODNs were delivered intracellularly using a cell-penetrating-peptide and found to impede HIV-1 replication in primary human cells at nanomolar concentrations. Extensive analysis showed that viral cDNA synthesis was severely impaired by mODNs. Partially resistant viruses with mutations in NC and RT emerged after months of passaging in cell culture. A HIV-1 molecular clone (NL4.3) bearing these mutations was found to replicate at high concentrations of mODN, albeit with a reduced fitness. Small, methylated ODNs such as mODN-11 appear to be a new type of highly potent inhibitor of HIV-1

Structural determinants of TAR RNA-DNA annealing in the absence and presence of HIV-1 nucleocapsid protein

Annealing of the TAR RNA hairpin to the cTAR DNA hairpin is required for the minus-strand transfer step of HIV-1 reverse transcription. HIV-1 nucleocapsid protein (NC) plays a crucial role by facilitating annealing of the complementary hairpins. To gain insight into the mechanism of NC-mediated TAR RNA–DNA annealing, we used structural probes (nucleases and potassium permanganate), gel retardation assays, fluorescence anisotropy and cTAR mutants under conditions allowing strand transfer. In the absence of NC, cTAR DNA-TAR RNA annealing depends on nucleation through the apical loops. We show that the annealing intermediate of the kissing pathway is a loop–loop kissing complex involving six base-pairs and that the apical stems are not destabilized by this loop–loop interaction. Our data support a dynamic structure of the cTAR hairpin in the absence of NC, involving equilibrium between both the closed conformation and the partially open ‘Y’ conformation. This study is the first to show that the apical and internal loops of cTAR are weak and strong binding sites for NC, respectively. NC slightly destabilizes the lower stem that is adjacent to the internal loop and shifts the equilibrium toward the ‘Y’ conformation exhibiting at least 12 unpaired nucleotides in its lower part

Le concept d’élites en Europe

Dans un contexte de renouvellement profond de l’historiographie en histoire sociale, les 23 communications qui constituent cet ouvrage collectif ont pour ligne directrice les milieux élitaires européens, analysés sous trois angles successifs. La première partie, centrée sur la méthodologie, l’épistémologie et l’historiographie s’intéresse aux caractéristiques des élites à travers les âges, de l’Antiquité au temps présent. La deuxième prend le parti d’éclairages successifs sur quelques sociétés de l’Europe occidentale ou centrale, de l’époque moderne à nos jours. La péninsule ibérique et le monde anglo-saxon y sont particulièrement mis en valeur. La dernière s’intéresse aux conceptions familiales et aux pratiques des élites, et ce, plus particulièrement dans la France d’Ancien Régime

Retrospective on the all-in-one retroviral nucleocapsid protein.

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