1,888 research outputs found
Human immunodeficiency virus type 2 (HIV-2): packaging signal and associated negative regulatory element.
No full textNote d'archivio sul Gallo di bronzo della basilica Vaticana
No full textA complemento delle riflessioni sull'ipotesi di datazione del Gallo e delle osservazioni critiche sulla tradizione letteraria riguardo alla sua pretesa collocazione sul campanile della basilica costantiniana, esposte in altra parte della presente pubblicazione, l'autore contestualizza le fonti d'archivio riguardanti il Gallo stesso, riassumendo sinteticamente, sulla base della documentazione superstite, gli spostamenti e gli interventi di restauro a cui esso è stato sottoposto dal tardo Cinquecento ad oggi.In addiction tothe considerations on the possible new dating of the Rooster and complementing the critical observations on the literary tradition concerning its presumed position on the bell-tower of the Basilica of Constantine presented in other articles of this publication, the author contextualizes the archival sources regarding the Rooster, briefly recapitulating, on the grounds of the surviving documentation, the various relocations and restoration work that it had undergone from the late 16th century to the present-da
Extracellular HIV-1 Tat protein up-regulates the expression of surface CXC-chemokine receptor 4 in resting CD4+ T cells
No full textHere we report that synthetic HIV-1 Tat protein, immobilized on a solid substrate, up-regulates the surface expression of the CXC-chemokine receptor 4 (CXCR4), but not of the CC-chemokine receptor 5 in purified populations of primary resting CD4+ T cells. The Tat-mediated increase of CXCR4 occurred in a well-defined range of concentrations (1-10 nM of immobilized Tat) and time period (4-8 h postincubation). Moreover, the increase of CXCR4 was accompanied by an increased entry of the HXB2 T cell line-tropic (X4-tropic), but not of the BaL macrophage-tropic strain of HIV-1. The ability of Tat to up-regulate CXCR4 expression was abrogated by the protein synthesis inhibitor cycloheximide, clearly indicating the requirement of de novo synthesis. As Tat protein is actively released by HIV-1 infected cells, our data indicate a potentially important role for extracellular Tat in rendering bystander CD4+ T cells more susceptible to infection with X4-tropic HIV-1 isolates
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