Pathogenic New World hemorrhagic fever mammarenaviruses (NWM) utilize Glycoprotein 1 (GP1) to target the apical domain of the human transferrin receptor (hTfR) for facilitating cell entry. However, the conservation between their GP1s is low. Considering this and the slow evolutionary progression of mammals compared to viruses, therapeutic targeting of hTfR provides an attractive avenue for cross-strain inhibition and diminishing the likelihood of escape mutants.
View Article and Find Full Text PDFUnlabelled: Virus entry into cells is a multistep process that often requires the subversion of subcellular machineries. A more complete understanding of these steps is necessary to develop new antiviral strategies. While studying the potential role of the actin network and one of its master regulators, the small GTPase Cdc42, during Junin virus (JUNV) entry, we serendipitously uncovered the small molecule ZCL278, reported to inhibit Cdc42 function as an entry inhibitor for JUNV and for vesicular stomatitis virus, lymphocytic choriomeningitis virus, and dengue virus but not for the nonenveloped poliovirus.
View Article and Find Full Text PDFPolarized epithelial cells that line the digestive, respiratory, and genitourinary tracts form a barrier that many viruses must breach to infect their hosts. Current understanding of cell entry by mammalian reovirus (MRV) virions and infectious subvirion particles (ISVPs), generated from MRV virions by extracellular proteolysis in the digestive tract, are mostly derived from in vitro studies with nonpolarized cells. Recent live-cell imaging advances allow us for the first time to visualize events at the apical surface of polarized cells.
View Article and Find Full Text PDFViral pathogens usurp cell surface receptors to access clathrin endocytic structures, yet the mechanisms of virus incorporation into these structures remain incompletely understood. Here we used fluorescence microscopy to directly visualize the association of single canine parvovirus (CPV) capsids with cellular transferrin receptors (TfR) on the surfaces of live feline cells and to monitor how these CPV-TfR complexes access endocytic structures. We found that most capsids associated with fewer than five TfRs and that ∼25% of TfR-bound capsids laterally diffused into assembling clathrin-coated pits less than 30 s after attachment.
View Article and Find Full Text PDFViruses coopt cellular membrane transport to invade cells, establish intracellular sites of replication, and release progeny virions. Recent genome-wide RNA interference (RNAi) screens revealed that genetically divergent viruses require biosynthetic membrane transport by the COPI coatomer complex for efficient replication. Here we found that disrupting COPI function by RNAi inhibited an early stage of vesicular stomatitis virus (VSV) replication.
View Article and Find Full Text PDFVesicular stomatitis virus (VSV), a prototype of the Rhabdoviridae family, contains a single surface glycoprotein (G) that is responsible for attachment to cells and mediates membrane fusion. Working with the Indiana serotype of VSV, we employed a reverse genetic approach to produce fully authentic recombinant viral particles bearing lethal mutations in the G gene. By altering the hydrophobicity of the two fusion loops within G, we produced a panel of mutants, W72A, Y73A, Y116A, and A117F, that were nonfusogenic.
View Article and Find Full Text PDFMicrobial pathogens exploit the clathrin endocytic machinery to enter host cells. Vesicular stomatitis virus (VSV), an enveloped virus with bullet-shaped virions that measure 70 x 200 nm, enters cells by clathrin-dependent endocytosis. We showed previously that VSV particles exceed the capacity of typical clathrin-coated vesicles and instead enter through endocytic carriers that acquire a partial clathrin coat and require local actin filament assembly to complete vesicle budding and internalization.
View Article and Find Full Text PDFPositive-strand and double-strand RNA viruses typically compartmentalize their replication machinery in infected cells. This is thought to shield viral RNA from detection by innate immune sensors and favor RNA synthesis. The picture for the non-segmented negative-strand (NNS) RNA viruses, however, is less clear.
View Article and Find Full Text PDFMany viruses that enter cells by clathrin-dependent endocytosis are significantly larger than the dimensions of a typical clathrin-coated vesicle. The mechanisms by which viruses co-opt the clathrin machinery for efficient internalization remain uncertain. Here we examined how clathrin-coated vesicles accommodate vesicular stomatitis virus (VSV) during its entry into cells.
View Article and Find Full Text PDFProc Natl Acad Sci U S A
December 2005
RNA interference (RNAi) is a sequence-specific gene-silencing mechanism triggered by exogenous dsRNA. In plants an RNAi-like mechanism defends against viruses, but the hypothesis that animals possess a similar natural antiviral mechanism related to RNAi remains relatively untested. To test whether genes needed for RNAi defend animal cells against virus infection, we infected wild-type and RNAi-defective cells of the nematode C.
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