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Several major human pathogens, including the filoviruses, paramyxoviruses, and rhabdoviruses, package their single-stranded RNA genomes within helical nucleocapsids, which bud through the plasma membrane of the infected cell to release enveloped virions. The virions are often heterogeneous in shape, which makes it difficult to study their structure and(More)
Mammals encode proteins that inhibit viral replication at the cellular level. In turn, certain viruses have evolved genes that can functionally counteract these intrinsic restrictions. Human CD317 (BST-2/tetherin) was recently identified as a restriction factor that blocks release of HIV-1 from the cell surface and can be overcome by HIV-1 Vpu. Here, we(More)
Direct cell-cell spread of Human Immunodeficiency Virus type-1 (HIV-1) at the virological synapse (VS) is an efficient mode of dissemination between CD4(+) T cells but the mechanisms by which HIV-1 proteins are directed towards intercellular contacts is unclear. We have used confocal microscopy and electron tomography coupled with functional virology and(More)
Correlative electron and fluorescence microscopy has the potential to elucidate the ultrastructural details of dynamic and rare cellular events, but has been limited by low precision and sensitivity. Here we present a method for direct mapping of signals originating from ∼20 fluorescent protein molecules to 3D electron tomograms with a precision of less(More)
HIV-1 assembly and release are believed to occur at the plasma membrane in most host cells with the exception of primary macrophages, for which exclusive budding at late endosomes has been reported. Here, we applied a novel ultrastructural approach to assess HIV-1 budding in primary macrophages in an immunomarker-independent manner. Infected macrophages(More)
The filoviruses, Marburg and Ebola, are non-segmented negative-strand RNA viruses causing severe hemorrhagic fever with high mortality rates in humans and nonhuman primates. The sequence of events that leads to release of filovirus particles from cells is poorly understood. Two contrasting mechanisms have been proposed, one proceeding via a "submarine-like"(More)
Formation of coated vesicles requires two striking manipulations of the lipid bilayer. First, membrane curvature is induced to drive bud formation. Second, a scission reaction at the bud neck releases the vesicle. Using a reconstituted system for COPI vesicle formation from purified components, we find that a dimerization-deficient Arf1 mutant, which does(More)
Endosomal sorting complex required for transport (ESCRT) machinery supports the efficient budding of Marburg virus (MARV) and many other enveloped viruses. Interaction between components of the ESCRT machinery and viral proteins is predominantly mediated by short tetrapeptide motifs, known as late domains. MARV contains late domain motifs in the matrix(More)
Direct cell-cell spread of Human Immunodeficiency Virus type-1 (HIV-1) at the virological synapse (VS) is an efficient mode of dissemination between CD4 + T cells but the mechanisms by which HIV-1 proteins are directed towards intercellular contacts is unclear. We have used confocal microscopy and electron tomography coupled with functional virology and(More)
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